maximizing piston to bore ring seal



maximizing piston to bore ring seal

Postby grumpyvette » November 14th, 2010, 8:02 am

From the February, 2009 issue of Circle Track
By Jeff Huneycutt

Piston Ring Prep
It can be a hassle filing...

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Piston Ring Prep
It can be a hassle filing three sets of rings per cylinder, but when done correctly the results can mean more power and less fall-off before the next rebuild.

Most of us consider piston rings little more than a necessary evil. That's probably because grinding rings is a time-consuming chore. And who hasn't accidentally ground a gap too large and wasted both time and money ordering up a replacement?

But when done right, piston rings can create a power advantage by maximizing dynamic engine compression while still maintaining good oil control. This involves both proper selection for the intended use and proper preparation when gapping your rings. To get more information on making your piston rings work for you, we spoke with engine builder Keith Dorton, owner of Automotive Specialists.

The purpose of piston rings is to seal the gap between the sides of the piston and the cylinder wall. On almost all stock car pistons there are three rings. The top ring is in direct contact with the combustion flame and sees the most heat. Because of that, it usually has a moly coating to make it better able to withstand the harsh environment. For racing, the primary purpose of the top ring is to effectively seal the combustion chamber to maintain compression.
Piston Ring Prep
Here is a ring that hasn't...

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Piston Ring Prep
Here is a ring that hasn't been ground properly. As you can see, the ends are no longer square to each other. It may not seem like much, but this can lead to a power-robbing loss of combustion pressure.

In OEM applications where a set of rings must be expected to last over 100,000 miles, the second ring is also expected to help maintain compression. But for racing, this isn't an issue. Instead, the second ring mostly helps with oil control. You do not want the second ring to provide too much of a seal because in a high-rpm application like racing, combustion pressure that passes the top ring and gets caught by the second ring can lead to ring flutter in the top ring. This should be avoided at nearly all costs.

The second ring is typically constructed from softer ductile iron because it doesn't see the heat that the top ring is subjected to, and also because the softer material helps the ring seal to the cylinder wall. The face of the ring also typically has a taper to it so that only the bottom portion of the ring actually touches the cylinder wall. This helps it function better as an oil scraper. The taper wears over time, and once it wears so much that the entire face of the ring is in contact with the cylinder wall, the ring's usefulness is long gone.

most applications would have a ring gap of about .004-.005 per inch of bore diam.
but tests have shown even a .050 end gap has only a marginal effect on engine power or blow by, simply because at even 1000rpm theres slightly more than 8 power strokes per second, and the pressure is ner max mostly in the 10 degrees before and 30 degrees after TDC, theres very little time to force much thru a .005 or less piston to bore clearance and two .050 end gaps even if that was the case

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BORING and HONING a blocks bore are best done at a local machine shop where clearances and surface finish are more accurately controlled, BUT, IF your going to be honing the bores for MOLY rings I,d suggest a 240-280 grit hone a 45 degree cross hatch angle and a constant flow of flushing liquid washing over the stones and bore surface to keep the stones from clogging with micro grit trash, that gets removed from the high points in the bore surface.
Ive used both a flush of 90% diesel fuel mixed with 10% marvel mystery oil, as a flush and Ive used hot water with a couple teaspoons of dawn dish washing soap, both work, but I think the hot water and dawn solution produced the most uniform result, on the bore surface but that requires a good deal of cleaning and washing the block just like the diesel fuel mix as you darn sure want to remove all traces of grit and prevent rust forming from moisture so after hone work I power wash the block with a pressure washer,, flush the surface with alcohol paint thinner as it tends to get under and lift out micro crud and speed surface dry time ,then I spray it over with WD40 and heat it with a heat gun to remove moisture traces then re-spray it with WD, 40
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http://www.harborfreight.com/1600-watt- ... 69342.html
BTW GAPLESS PISTON RINGS HAVE TWO PIECES THAT EACH MUST BE GAPPED< THE IDEA IS THAT THE TWO GAPS IN THE SET ARE ON OPPOSITE SIDES OF THE PISTON GROOVE
Although Dorton uses a powered ring grinder that greatly speeds up the process, a manual crank-style grinder, such as this one from Powerhouse Products, works just as well (if you are willing to be patient) and costs a lot less.

Some high-end ring packs will also feature a second ring with a Napier-style design. A Napier ring has a "ridge" that steps up so that the inside of the ring is thicker than the outside. Dorton says that the effect is to provide more material inside the ring land for increased rigidity, while the face of the ring that contacts the cylinder wall is thinner to reduce sliding friction between the ring and the cylinder bore. Dorton says the Napier design works but, as you might expect, the extra engineering does come with extra costs attached. Usually, Dorton only uses Napier-style rings in dry sump applications where the vacuum created in the crankcase helps keep oil out of the combustion chambers.

Finally, the oil ring is actually an assembly of two scraper rings and a center expander ring. As it's named, the oil ring's only job is to pull oil off the cylinder walls and dump it into the oil pan.

Most ring packs for street applications come pre-gapped. But that simply isn't precise enough for racing where gaps should be accurate to within 0.001 inch or less. The purpose of the gap is to allow enough room so that the ring can expand once the engine is hot so that the ends almost touch. The trick is to get the gap as small as possible when the engine is hot without the ends butting. It's better to go too large rather than too small because if the ends do butt, it will lead to scuffing the cylinder walls, micro-welding of the ring to the piston's ring lands, and possibly even breaking the ring.

After filing your ring and...


After filing your ring and before trial fitting inside the cylinder bore, take a moment to knock the burr off of the outside edge of the ring. If this isn't done it can throw off your gap measurement.

Dorton uses a powered ring filer, but a more traditional crank-style ring filer is a more economical option for those of us who aren't building engines for a living. No matter what you use, you must be careful to only make small cuts on the rings because you can't put material back on. Also, be prepared to put in a little practice with a couple of old rings before you can reliably make smooth, perpendicular cuts on the rings.

The size of the ring gap necessary varies by the amount of heat generated and which ring you are talking about. But the variables are mostly limited to whether you are running naturally aspirated or using a turbocharger. Fortunately, for stock car racing, there isn't as much variance whether we are talking about Street Stocks or an ARCA engine, so the following recommendations hold true no matter what division you race.

Because the top ring sees the most heat, it requires the largest gap. Dorton says that for anything with a bore between 4.00 and 4.100 inches, a 0.022-inch gap should work fine. In fact, Dorton says he has experimented with gaps everywhere between 0.016 and 0.030 inch on the dyno on several different styles of engines and seen no real difference in terms of power.
Piston Ring Prep
Insert the ring into the cylinder...


Insert the ring into the cylinder and then use a ring-squaring tool to make sure it is perpendicular to the centerline of the cylinder bore. If you don't have a squaring tool, you can use a piston that has the top ring installed. Simply install the ring in the top of the bore and then use the piston to push it into the bore until the ring installed on the piston contacts the deck of the block all the way around.

On the same piston, the second ring should be gapped between 0.016 and 0.020 inch. Less gap is necessary because the second ring is protected from hot combustion gasses by the top ring, but you still don't want it too tight to eliminate the possibility of ring flutter on the top ring.

Finally, Dorton recommends going in the opposite direction for the oil ring. In order to get maximum oil control, the gaps in the oil rails need to be as tight as absolutely possible. Dorton says that as long as you can fit the rings inside the cylinder bore without them butting then you will be fine, but a practical gap should be between 0.006 and 0.008 inch.

Rings are critical for proper engine operation, but they also cost you some power. The movement of the rings against the cylinder walls creates drag, and any portion of that drag you can eliminate while still maintaining proper combustion in the chambers, the better off you will be. To get a better idea of how much power we are talking about, Dorton mentions a test he did several years ago with a race engine. After dyno'ing the engine to determine a baseline, he says he pulled the heads, dropped the oil pan, and removed all the pistons and rods. He pulled the second ring off of all the pistons, rebuilt the motor right there on the dyno stand, and fired the engine back up. With the 0.060-inch second ring removed from all eight pistons the engine gained 5 hp over its 400hp baseline!
Piston Ring Prep
After the ring is correctly...


After the ring is correctly gapped, use a honing stone to knock the burr off of the edges of the ring. Make sure only to knock the burr off and not round the edges of the ring as you can see here. This will kill the ring's ability to seal off the combustion chamber.

This is why most piston manufacturers now offer race-quality pistons with ring lands designed for thinner rings. The reduced surface area contacting the cylinder walls creates less drag. Where most performance ring packages used to be 1/16, 1/16, and 3/16, new metric-based rings sized at 1.2, 1.2 and 3 millimeters are gaining popularity.

One drawback is that low-tension rings simply do not do as good a job of scraping oil off of the cylinder walls. Fortunately, the solution is to use pistons with gas ports. Gas ports are simply slots drilled into the top of the upper ring land that allows combustion pressure to get behind the ring. This pressure from combustion pushes the ring down against the bottom of the piston's ring land and out against the cylinder wall, improving cylinder sealing. Then, on the exhaust stroke when the pressure is reduced, the friction between the ring and the cylinder wall is greatly reduced.
Piston Ring Prep - Ringing In The Power

This is a good comparison...


This is a good comparison of two second rings with the tapered-face design that have seen different amounts of use. The upper ring has not seen excessive use, and only a small part of its face is shiny (from direct contact with the cylinder bore wall). The outside face of the lower ring is completely shiny, meaning that it is worn out.

The oil ring is a completely different animal than the top two rings. Unlike the others, the tension of the oil ring is controlled by the radial thickness of both of the oil rails as well as the size of the gap in the expander ring. By manipulating the different parts of the oil ring to reduce the tension, Dorton has found a couple of horsepower on the dyno without harming oil control.

The radial thickness of the rings can vary by as much as 0.015 inch. This variance comes in different production runs, so you shouldn't see that much change in one pack of rings. But because the ID of the oil ring sits inside the expander, a ring with a greater radial thickness will have more tension than a ring with less radial thickness. This is true even if both rings have the same end gap.

Begin by separating out your rings according to thickness. Keep the thinnest and save the rings with the greater radial thickness for a later rebuild. You may need to go through a few packs to get a good set. If you cannot afford to purchase several sets of rings, see if your local engine builder would be willing to swap a few with you.

You can also check for variances in the gap in your expander rings. A properly sized expander ring will fit in the cylinder bore so that the ends butt without buckling the ring. You cannot gap an expander ring, but if you have one that has a gap when placed inside the bore, you can match it with scraper rings that have a greater radial thickness.

You can actually feel the difference in a well-matched set of low-tension oil rings. Install both oil rings with the expander on a piston and install it upside-down in a dry cylinder bore. Slide the piston up and down inside the bore and get a feel for the resistance. Now try the same thing with a set of oil rings with a greater radial thickness matched to the same expander ring and notice the difference.

(years ago the thinking was that because the second rings did not endure the same high temperatures as the top ring the second lower ring could have less gap as it would expand less from heat, modern thinking resulting from testing shows the second ring should have a slightly wider end gap to prevent the stop ring from loosing its seal pressure and developing RING FLUTTER at higher rpms, the problem is that "higher rpms" differ with every combo built)
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bores must be honed with a deck torque plate to simulate the stress of a installed cylinder head stress , the torqued bolts exert on the bore walls, the torque plate induces and duplicates that stress so that the bore walls will be pulled into the same relationship when you hone the walls concentric, rings won,t seal correctly in a non concentric bore
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gaps must be correct for the application
RINGS MUST BE MEASURED WHILE SQUARE IN THE BORE< A RING SQUARE TOOL HELPS, I USUALLY PLACE THEM ABOUT 1" DOWN THE BORE THEN MEASURE END GAP, see later in the thread for how to make a good but dirt cheap ring square tool
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ring ends must be, correctly gaped, cut parallel and de-burred before installation
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if the valve train clearances and rings are installed correctly ,cylinder pressure helps ring seal and break-in so don,t be afraid to keep the engine constantly changing rpm and load as this seats both the rings to cylinder walls and throws extra oil mist on the cam lobes, lifters and cylinder walls and maintain enough oil pressure to keep the rockers properly lubricated
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use of the proper tool helps keep the gap and ring ends square and parallel

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http://courses.washington.edu/engr100/S ... 0Rings.htm
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http://www.kb-silvolite.com/news.php?ac ... ad&N_id=27

http://www.wiseco.com/PDFs/Manuals/RingEndGap.pdf

http://www.circletrack.com/howto/1818/index.html

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remove the burrs from the ends of the ring after gapping them,but don,t round off the ring ends like the left side, in his fingers here

http://courses.washington.edu/engr100/S ... 0Rings.htm

viewtopic.php?f=51&t=588&p=764&hilit=hone+plates+block#p764

http://www.totalseal.com/TechPage.aspx#trRingInstall

http://www.youtube.com/watch?v=ZVSd8-b0Ntk

http://www.circletrack.com/techarticles ... index.html

http://www.cp-carrillo.com/LinkClick.as ... D&tabid=83

http://circletrack.automotive.com/11015 ... index.html

http://www.fme-cat.com/Docs/1204.pdf

http://www.beckracing.com/page05.htm

viewtopic.php?f=53&t=5454

http://kb-silvolite.com/article.php?action=read&A_id=10

http://kb-silvolite.com/article.php?action=read&A_id=56

http://kb-silvolite.com/article.php?action=read&A_id=32

http://kb-silvolite.com/article.php?action=read&A_id=5

http://www.circletrack.com/enginetech/c ... index.html

you generally only need to grind the tips of the expander ring (RARELY NEEDED OR DONE) or bend them only a tiny bit (PREFERRED METHOD)

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if at all, in most cases they come out of the packager ready to install (THERE ARE EXCEPTIONS) the expander ring should sit level in the bore , and sitting parallel with the deck with minimal tension, their job is mostly maintaining consistent space between the wiper rings, which generally use a .018 gap and allowing oil to drain back thru the groove drain slots in the piston, its the oil scraper rings not the expander that provide much of the MINIMAL tension required to keep the oil ring in contact with the bore surface
as always a call to the manufacturer is a good idea, if you have questions because different ring designs require different clearances

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http://www.hastingsmfg.com/ContentData. ... ntentid=65

http://www.hastingsmfg.com/ServiceTips/ ... depths.htm

http://www.youtube.com/watch?v=slS8CUHRNkc

http://www.chevyhiperformance.com/tech/ ... index.html

http://www.enginebuildermag.com/Article ... rings.aspx

http://www.enginebuildermag.com/Article ... mance.aspx

http://www.hotrod.com/techarticles/engi ... ewall.html

http://www.kb-silvolite.com/assets/auto ... ctions.pdf

http://www.superchevy.com/technical/eng ... ewall.html

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NOTICE the two totally different OIL ring scraper ring widths in this picture above,OIL RINGS come in dozens of designs so, you can not use all oil rings on all pistons and you can,t swap expanders and wipe rings thru different designs, and you must verify piston groove measurements , measure carefully as the piston groove depth and back clearance must match the rings you use or youll have major problems

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heres a few threads related to maximizing ring seal,and related info

http://www.circletrack.com/howto/4639_m ... to_10.html

http://www.wiseco.com/PDFs/Manuals/RingEndGap.pdf

viewtopic.php?f=53&t=3897&p=11709&hilit=hone#p11709

viewtopic.php?f=53&t=509&p=11324&hilit=hone#p11324

viewtopic.php?f=51&t=125&p=10972&hilit=hone#p10972

viewtopic.php?f=53&t=2795&p=8966&hilit=hone#p8966

viewtopic.php?f=53&t=2837&p=7342&hilit=hone#p7342

viewtopic.php?f=51&t=588&p=7313&hilit=hone#p7313

viewtopic.php?f=53&t=852&p=1311&hilit=ring+compressor#p1311

viewtopic.php?f=50&t=55&p=68&hilit=ring+compressor#p68

viewtopic.php?f=53&t=110&p=3631&hilit=hone#p3631

viewtopic.php?f=53&t=247

for anyone reading thru this thread, be aware that the piston rings have a side that faces up , its usually marked with a DOT but some rings have a beveled inner edge that faces up instead, get the rings installed upside down in the piston grooves and your guaranteed to have sealing and oil burning issues, most rings come packaged in separate packages , for top, second and oil rings, inspect them carefully as you don,t want second rings installed in top ring grooves or to have rings installed upside down or with the wrong end gaps
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related threads

viewtopic.php?f=53&t=247

viewtopic.php?f=53&t=852

viewtopic.php?f=53&t=3897

viewtopic.php?f=53&t=5454

viewtopic.php?f=53&t=4630

viewtopic.php?f=53&t=509

viewtopic.php?f=53&t=3449

viewtopic.php?f=53&t=726

viewtopic.php?f=53&t=2795

viewtopic.php?f=53&t=2837

viewtopic.php?f=51&t=3774

viewtopic.php?f=51&t=588
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
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Re: maximizing piston to bore ring seal

Postby grumpyvette » January 14th, 2011, 12:07 pm

Low Cost Quality Honing For The Small Shop


By David McLain


My son and I run a small automotive machine shop doing engine rebuilding and custom machine work in rural Missouri. We try to do the very best work possible all the time. Whether we are rebuilding a Ford 8N or a 427 Corvette engine, we use the same amount of care doing the job. When our customers pick up their parts, they are confident that the job has been done correctly.

Who should read this article?
This article was written for the small shop machinist who may not have every piece of high tech equipment in the world at his or her disposal. This small shop is trying to turn out quality work and at the same time make a profit. Also, if any of the following "warning signs" exist in your shop you should read this article on honing:

1. The engines you bore and hone seem to use oil after only a few thousand miles.
2. You feel the piston rings that come in engine kits cause engines to use oil and have excess blow-by.
3. You hate honing engines because you always end up with tapered cylinders.
4. The last time you tried to hone an engine, the hone locked up, and the drill twisted your arms and hit you in places I can't mention in this article.

Source of information
I have tried to take 35 years of automotive machine shop experience, plus what I have seen others doing both right and wrong, and cram it all into these few short pages on honing. If what we talk about here helps you do a better job honing engines and making more money, we will have done our job.

My son and I enjoy doing machine shop work, but we have found that we must make a profit in order to stay in business. We need to turn out good work in order to keep customers coming back, and we need to charge a fair price for doing it. My equipment sales representative who calls on our shop in Cuba, MO, reminds me of this very important point almost every time he visits. He often tells me that as an industry we work too cheap. He says, "You have to charge for what you do."

How to read this honing article
I think most of us in the automotive business like to page through technical magazines and look at the pictures. We often read the captions under the pictures and think we have truly absorbed what the writer was trying to tell us. I have included a number of pictures to capture your attention so go ahead and take a look, but come back and read the rest of the story. I think you will need to read the story at least once, perhaps twice, to understand thoroughly what we are doing and why.

Why hone?
As machinists we are called upon to bore and hone engine cylinders as part of our job. It is a fact, engines do wear out - mostly from what people do or fail to do to them. If engines did not wear out, we would all be looking for different work.

Sometimes we fail to mention honing when we tell a customer that we are going to bore his or her engine to renew the worn cylinders. Honing is perhaps the most time consuming, least understood, yet most important part of the entire rebuilding process. Honing also requires a good deal of skill on the part of the machinist doing the work.

Sure it would be nice to have a new power hone to recondition our cylinders, but as I said before, this article is written for the shop owner that does not have every piece of equipment he'd love to own.

In our shop we use a Van Norman boring bar that has been my friend for more than 30 years. I think my 777S is trying to out live me. I can depend on my boring bar to bore straight, round and right on size every time. I keep the tool bits sharp and the cylinders look great when the bar gets finished.

However, I know if I were to look very closely at the cylinder bores, I would find that the surface finish is still much too rough for new pistons or rings. We must hone the cylinders to obtain a surface finish smooth enough for the new pistons and rings.

Getting set up for honing
When I rebore a cylinder I leave three thousands (.003") for honing. For example, if I am boring a 4.0" cylinder +.030", I set the tool bit at 4.027". This leaves .003" for honing .

It's a really good idea to have the pistons you are planning to use in your hands, before you start to bore the engine. This allows you to measure the pistons and make certain that you will have the correct clearance between the piston and cylinder wall when you get finished boring and honing. When I am finished boring all the cylinders, I remove the engine from my boring stand and move it to an area of our shop where I do my honing.

Here is an important shop tip to keep in mind when boring an engine cylinder. Let the boring bar go down far enough so that when you hone the cylinder, the hone will not catch the ledge above the main webs in the crankcase. On a Chevy 350, for example, I let the bar go down until it almost starts to touch the main web.

After you finish boring an engine, do not wipe or even touch the freshly bored cylinders. In other words, keep your oily mitts off the cylinder walls. Also, do not spray anything on them. Do not put the block back in the hot tank or spraywasher. You should be ready to go directly to the honing operation when you finish boring. Shop towels and hands have oil on them; even clean shop towels have oil on them. Freshly bored metal will pick oil up like a magnet.

We are now ready to start honing our block dry, and we want to keep it that way until we have removed .002" of the .003" we allowed for honing. Take time to secure the engine block so the deck surface is facing up. We have two sets of simple stands made of angle iron to hold most V6 and V8 blocks so that the deck surfaces face up when I sit the block on the floor.

The stands we use bolt to the pan rails of the engine block. If you are trying to hone your engines on a workbench or engine stand forget it! Blocks of wood don't work either. The engine you are going to hone must be mounted solid!

Before we get started, let's talk about some of the equipment you will need to hone engine cylinders. You will need a good micrometer set and the standards to check them. A dial bore gauge is almost a must, but you can get along without one if you have to. We use a Sunnen dial bore gauge in our shop.

Here is a tip that may save you some money. When you have finished using the dial bore gauge lay it down on a flat surface, not on the top of the engine deck. The dial bore gauge will roll if you place it on the narrow engine deck surface. Just like dropping a piece of jelly bread, the dial gauge will hit the floor face down every time.

You should have a telescopic gauge to use with the micrometer to double check the cylinder bore size before and after honing. Of course, you must also have a hone. We use a Sunnen AN series hone body and stones. We made our own drive shaft to fit the hone body. Our design allows the shaft to slip if the hone happens to lock. The Sunnen drive shaft is fine, but it is designed to twist off if a lock-up occurs.

Here is another tip. If you are using the Sunnen hone and drive shaft, and it gets broken, replace it. Do not try to beef it up by welding extra reinforcing material to it. Sunnen designed it to break if the hone locks up.

Now you need something to drive the hone. Use a good electric drill that has an "on" and "off" trigger switch. We use a Black & Decker Professional model half-inch drill with reverse. The drill must be a medium-speed unit.

The rpm the drill turns at, and the speed with which you stroke the hone up and down the cylinder, will determine the angle of the cross hatch marks left by the hone. The cross hatch marks help hold oil on the cylinder wall during break-in. You don't want the cross hatch too flat or too steep.

After you start honing your first cylinder, take a few minutes to look at the cross hatch lines. You will quickly get a feel for how fast you must stroke the hone. Do not spend a whole lot of time measuring the angle of the cross hatch. I don't think it makes a lot of difference anyway. Shoot for an angle of about 35° to 45° on the lines. A little more or a little less won't make any big difference.

Cylinder wall finish, however, will make a big difference, so pay more attention to it. Stay away from those old gear drive drills with powerful motors and low gearing. They have so much torque, and they take far too long to stop turning when you let go of the trigger. You may be sorry! You could end up hanging onto the drill for dear life while you and the drill go round-and-round until the plug pulls out of the wall!

Now we must attach the drill and hone to something that will help counterbalance their weight and that will provide a positive down-stop for the hone. I use a device made by Sunnen that has a spring and a rod with a positive stop adjustment on it. The spring helps support the drill and allows us to move the hone up and down with very little effort. If you do not have this device, buy one or make one.

I attach the drill to the counterbalance device with a short length of chain to the threaded hole in the end of the drill motor. I have a chain hoist directly above the area where I hone my engines. I hook the spring assembly with the hone and drill right on the chain hoist. The chain hoist allows me to raise or lower the hone and drill assembly quickly and very precisely.

I have seen many people trying to hone a block by hand, by just holding the drill without some type of support. You are asking for problems if you try it. That pretty much covers the major equipment you will need. You should have most of it already.

One more comment about the hone. You must use a rigid type hone to hone a block after boring. Do not even try to hone a block using a springloaded hone or a brush hone. They have a purpose in life, but they are not designed to remove .003" metal after boring!

Having just finished boring our engine block, we now move it over to the area of the shop where we are going to hone it. We have mounted the engine block so it wont move around from the torque of the hone. If you are going to use a torque plate during the honing process, torque it in place now.

Make sure the hone body is clean and free from oil and install your set of AN-100 stones (or equivalent). We start with the coarse grit stones first. These stones are to be used dry. They go into the holes on the hone body marked with the "X". Do not touch the stone surface if you can help it.

By the way, keep all your stone sets in their own boxes when they are not being used. Stones become a matched set as soon as they are used and must be kept together. If one stone gets damaged, the whole set is junk. Normally a set of stones will hone quite a few cylinders before they become worn out and need to be replaced.

Set the block under the hone and push the hone down until it is stopped by the positive stop on the spring fixture. Now, using the chain hoist, lower the hone down into the first cylinder until the stones just protrude through the bottom of the cylinder. Adjust the stones out until they lightly contact the cylinder wall.

Lightly pulse the drill motor and move the stones down farther through the cylinder with the chain hoist until they come out the bottom of the cylinder about one inch. When you feel them just begin to bump the crankcase webs, raise the chain hoist slightly. Note, I said lightly pulse the drill, and move slowly, as you go down into the crankcase. You do not want to bang your new stones into something down in the block.

The positive stop on the hone counterbalance allows you to go as far down into the cylinder as possible on every stroke without the stones hitting the crankcase webs. It is very important to have the stones come out the bottom of the cylinder while you are honing to keep the cylinder straight.

Now let's get started actually honing. Crank up the pressure on the stones, and begin to stroke the hone up and down the cylinder. Go all the way down and contact the positive stop on every stroke. The hone should also come out the top of the cylinder about one inch on each stroke.

If you hone too much on the top of the cylinder, you will taper the bore. You must get a feel for how much tension to place on the stones and how fast to move the hone in the cylinder. When the stones are cutting right, there will be a considerable dragon the drill motor. If you put too much pressure on the stones they will make lots of noise and not cut any faster. Too much pressure will also cause excess heat and stone wear.

If you happen to get oil on the dry stones they will stop cutting and become loaded with metal and stone material. Stop and try to scrape the junk off the stone surface with an old file. I have used lacquer thinner in extreme cases to clean the AN 100 series stones. However, it's best not to get oil on the stones in the first place.

Since you are working these stones dry, dust will be produced. Use a dust collector or shop vac to collect the dust while you are working. I usually wear a dust mask while boring and honing. You will need to hone a little and stop and measure until you get a feel for how fast the metal is coming out. Use your micrometer to set the dial bore gauge to the finish bore size you want, and start checking the cylinders.

As you hone, the cylinder will become warm. This may give you a false reading. You may think you have removed more metal than you really have. Let the block cool a few minutes and go back and check again. You want to use the AN 100 stones until you have removed the first .002" of metal. Do all the cylinders in the block with the dry stones before you change to the finer stone sets.

Here is a tip that you won't find in the books. This is something I found out on my own some years ago. If for some reason the stone set you are using or the cylinder you are honing becomes tapered, you may be able to save the day and the stones. Stones do not come from the manufacturer tapered. They get that way because you are not stroking far enough out the bottom, or you're too far out the top of the cylinder.

Try this before you junk the stone set. Take the stones out of the hone body holes with the "X" mark. Now put them back into the holes without the "X" mark. You will have to turn the stones upside down to do this. Put the adjuster back in and put the hone back in the tapered cylinder. Expand the stones out by turning the adjuster the opposite direction.

Now run the drill in reverse and stroke the hone up and down the tapered cylinder. You must run the drill in reverse to do this or it will lock up. You will be surprised how quickly the stones will straighten out. This will also remove the taper from the cylinder (At least one supplier of stones does not recommend stones be turned upside down and taper corrected as described in the above procedure. The company says if stones show taper they should be either filed, put into a truing sleeve, or replaced with new stones. When possible, proper overstroke will prevent stone taper. - Editor's note).

When you stop honing to check the cylinder for size, be sure to keep moving the hone up and down until the drill stops turning. The hone will usually make about one or two turns after the drill trigger is released. It takes about 100 strokes to remove about .002" of metal from a 4.0" cylinder. I usually count the strokes so I have some idea when to stop and check the cylinder for size.

Out of the dry and into the wet
Your cylinders are now honed to within .001" of the desired finish size. They should be straight and round, and the cylinder walls should look bright and clean if you wipe them with a clean dry cloth, not a shop towel!

You should have checked the cylinders with the dial bore gauge after the block cooled, and now you are ready to go to a finer stone set. Install the AN-200 set and using the same procedure as with the AN-100 stone set, stroke the cylinders and at the same time add honing oil with a pump oiler. Use plenty of oil as you hone with the AN-200 stones.

After about 30 strokes check the cylinder for size. You can turn off the dust collector now. You will be able to feel the hone begin to pick up speed as the cylinder surface gets smoother. You should now be down to less than .0005" of the finish size.

After you have honed all the cylinders with the AN-200 stones, switch to the AN-300 set and again hone with oil for about 30 strokes. The oil will keep the stones clean and form a slurry in the cylinder as you hone. You should now be at the final size. Allow the block to cool and recheck with the dial bore gauge.

Honing a block by hand does take time. I spend about one hour honing a V-8 block. It takes time to do the job right. You will quickly get a feel for what is happening in the cylinder when you hone by hand. For example, when a torque plate is bolted to the deck, you will feel the out-of-roundness caused by the bolt torque as you begin to hone the cylinder. As the honing progresses you will feel the torque on the drill become steady and smooth.

Following the above process will provide you with a surface finish between 15 and 20 micro inches. If you want a finer surface finish use the AN-500 stones with oil and hone another 10 to 15 strokes.

You're not done yet
The engine block is now finish honed and you have checked all the cylinders for taper and size. Double check your work with your telescopic gauge and micrometer.

You should always clean the block before it leaves your shop. We charge one hour labor to clean a customer's block after boring and honing. You can tell the customer that he needs to clean the block because there is lots of honing grit in the cylinders, but most customers will not clean the block themselves correctly. If you want them to have success with your rebore jobs you better do the job yourself.

My son, David, is an expert at cleaning blocks after honing. He uses hot water, Tide, and good bore brushes. He cleans all the cylinders and all the oil passages by hand.

The crankcase webs need special attention, too. Grit loves to hide in the crankcase webs. After all the hand work we pressure wash the block with very hot water and then transfer it to a mineral spirits bath in a clean solvent tank. Here we hand scrub all the cylinders with clean solvent to remove any water from the pores of the metal.

You must act quickly after washing with hot water because rust forms almost immediately on the cylinder walls. After flushing the block with clean solvent put a light inside the engine case and look at the cylinder walls. They will be bright and very shinny with a good cross hatch pattern. The engine is now ready to be covered with plastic until it is assembled.

Checking your work
If you want to be sure you have done a good job of getting the surface finish right, purchase a profilometer from your shop supply source, or contact your local equipment rep and ask him to stop by and test some of your cylinders for the Ra finish. You can't tell how smooth the surface is by just looking or even feeling with your finger. The profilometer will give you an accurate measurement of the surface finish. Our own representative has tested our rebore jobs and found the finish to be right in there at 17-20 Ra.

Wrapping up
I realize what I have described is a long procedure with many steps. But I have found that this procedure also produces very good results. Many of our engines have gone well over 200,000 miles and are still performing with very little oil consumption and low blow-by.

We also use moly rings on almost every job except where excess dust will be encountered. In those engines we use chrome rings. I did not say it would be easy or quick, but I did say you could do very good work if you are willing to take the time to do it right.
Any type or size of cylinder can benefit from the Flex-Hone®. These abrasive bead style brushes are produced in standard diameters from 4mm to 36cm Eight abrasive types are offered including silicon carbide, aluminum oxide, boron carbide and diamond allowing the tool to be tailored to finish any base material. A choice of 11 different grit selections are available for precise control of finish parameters. The elimination of peaks results in rapid ring seating, better oil control, reduced seepage in hydraulic and pneumatic applications and provides better seal performance and longer seal life. Successful applications include firearm chambers, shotgun barrels, musical instruments, combustion chambers, air compressors, pumps, valve bodies, valve guides, brake cylinders, wheel cylinders and the list goes on and on.

Flex-Hone® tools are also very effective for cross hole deburring, port radiusing and edge blending. Because of its unique construction, the Flex-Hone® is self-centering, self-aligning, and self-compensating for wear so it does not require an elaborate set-up or special training. Deburring with ball hones can be effectively automated and combined in the machining process to allow a complete cylinder finish in one operation or it can be employed as a secondary operation with equal results.
BRM continues to apply our years of experience and patented Flex-Hone® technology to solve difficult deburring and surface finishing problems. Our Flex-Hone® for Rotors now brings the same benefit to create the ideal surface finish on brake rotors, fly wheels and clutch plates. The tool reduces friction induced braking noises by producing a surface that lowers harmonic vibrations and creates a non-directional cross-hatch pattern. The Flex-Hone® for Rotors is more cost effective than abrasive pads and it is ideal for both new and re-turned rotors and flywheels.

http://www.dartheadstv.com/video_detail.php?mId=13335

http://www.brushresearch.com/brushes.php?c1=2

they will last for dozens of engines if used correctly but they are not real in-expensive,or cheap, most good quality ball hones cost close to $100 each
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a ball hone with 320 grit used sparingly produces a very good surface finish for moly rings to seal with but a ball hone follows the cylinder wall surface irregularities even if its a bit egg shaped or hourglass or cone shaped so its NOT going to be ideal in a well worn cylinder because the rings will not be able to fully contact a non-cylindrical cylinder wall, equally at all points during the piston movement ,especially at higher rpms.



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cylinder hones that use use 3-0r-4 parallel stones will tend to only remove the higher surfaces peaks , and itsuse is more likely to maintain a true cylindrical surface, as the stones can,t drop into minor surface irregularities
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HONE WITH HONE PLATES to duplicate the stress the head bolts place on the cylinder walls to get a true round bore wall surface
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related info

http://www.project33.com/article.cfm?ID=36

viewtopic.php?f=53&t=509&p=632#p632

http://www.hastingsmfg.com/ServiceTips/ ... ishing.htm
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
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Re: maximizing piston to bore ring seal

Postby grumpyvette » January 14th, 2011, 12:09 pm

The Smooth Science of Cylinder Honing


By Larry Carley

Larry Carley

The basics of honing cylinder blocks hasn’t changed much in recent years, but what has changed are the type of abrasives being used by many engine builders.

Silicon carbide and aluminum oxide honing stones of various grits have long been used in power honing machines and portable hones to finish cylinder bores. These types of abrasives are popular with engine builders because of their flexibility and low cost.

But in recent years, a growing number of performance engine builders and custom engine builders have started using the same type of honing stones that production engine rebuilders and OEMs use: diamond abrasives.

Conventional vitrified abrasives cut cleanly and do an excellent job of finishing cylinders – provided the right honing procedure is used to achieve a bore finish that meets OEM specs or the ring manufacturer’s requirements. But as the stones work the surface, they experience a lot of wear. In fact, the stones wear almost as much as the metal surface in the bore. Consequently, the honing machine operator has to constantly monitor the honing process and compensate for stone wear to keep the bores round and straight.

Tim Mera of Sunnen Products Co. in St. Louis, MO, says conventional abrasives require a balance between cutting action and stone life. As a rule, harder metals require softer stones. A softer stone requires less honing pressure, produces less heat and causes less bore distortion. So the bond that’s used in conventional abrasives is designed to wear quickly and expose the abrasives for good cutting action.

OEMs and production engine builders, on the other hand, don’t have the luxury of being able to baby-sit their honing equipment. Because of their higher production volumes, OEMs and PERs have to run their honing operations at higher speeds and with less operator supervision – which means diamond honing stones in most cases.

Diamond has long been the material of choice for high speed, high volume honing applications because of its excellent wear characteristics. Stone life depends on the hardness of the abrasive, the hardness of the substrate that holds the abrasives, the hardness of the engine block, honing speed, load and the amount of metal that’s removed. Diamond is the hardest natural substance known, so it can hold a cutting edge much longer than a conventional abrasive. This means the bond that holds the diamonds can also be harder because it doesn’t have to wear away as quickly to expose fresh stones on the surface.

Typically, a set of conventional vitrified honing stones might do up to 30 V8 blocks (240 to 260 cylinder bores) before they’re worn out and have to be replaced. A set of metal bond diamond honing stones, on the other hand, might do as many as 1500 V8 engine blocks (12,000 cylinder bores) before they have to be replaced. That’s a huge difference.

However, diamonds require a sizable up-front investment. A set of stones can cost $600 to $700 – which is a big jump from $15 to $35 for a set of conventional honing stones. Consequently, many small custom engine builders say diamonds are too expensive for their purposes. They also say they can’t afford to buy several sets of diamond stones to cover all the different bore sizes they do.

Even so, when the longer life of diamond stones is compared to that of conventional abrasives, diamonds may be more economical in the long run, even for a small shop (assuming an operator doesn’t overstroke a bore and break a stone!).

Pim van den Bergh of K-Line Industries, Holland, MI, says he sees more and more shops switching to diamond for a variety of reasons. "We were one of the first to offer diamond for honing machines because we saw its many advantages." He says it gives very consistent results with minimal stone wear.

Pros & Cons Of Diamonds
Because diamond is a harder material and wears more slowly than conventional abrasives, it cuts differently and requires more pressure. Diamond tends to plow through a metal surface rather than cut through it. This can generate heat and distortion in the cylinder bore if the wrong type of equipment, pressure settings or lubrication is used in the honing process. When done correctly, though, it can actually improve bore geometry by producing a rounder, straighter hole.

Diamond is also good for rough honing cylinders to oversize because it can remove a lot of metal fast. But finishing requires at least a two-step procedure. Otherwise, the surface will be too rough.

If you’re switching from conventional stones to diamond, you’ll generally have to use a higher grit to achieve the same Ra (roughness average) when finishing a cylinder. For example, if you have been using #220 grit conventional stones to finish cylinders for chrome rings, the equivalent diamond stones might be a #325 grit. If you have been using #280 grit conventional stones to hone for moly rings, the diamond equivalent might be #550 grit stones. The actual numbers will vary somewhat depending on the brand and grade of the stones.

A cylinder bore must have a certain amount of cross hatch and valley depth to retain oil. However, it must also provide a relatively flat surface area to support the piston rings. Ring manufacturers typically specify a surface finish of at least 28 to 35 Ra for chrome rings, and 16 to 25 Ra for moly faced rings. These numbers can be easily obtained with diamond stones and brushing, say those who use this honing technique.

One rebuilder we spoke to says he uses #325 grit diamond stones to end up with an Ra finish in the 20 to 25 range, which he feels is about right for moly rings. For some applications, though, he uses a #500 grit diamond to achieve a smoother finish in the 15 to 20 Ra range.

Final Finish
Something else that’s different when honing with diamond is what diamond does to the bore surface. Diamond tends to leave a lot of torn and folded metal on the surface, causing sort of a smeared appearance that doesn’t make a very good bore finish. Consequently, finishing the cylinder requires a second step to remove the damaged material.

One way to get rid of this material is to plateau the surface with a fine grit conventional abrasive (like a #400 or #600 grit stone). All that’s needed are a few strokes to shave off the tops of the peaks. But, the most popular method for finishing the bores when using diamond stones is to sweep the bores with a flexible brush or a nylon bristle plateau-honing tool. Brushing helps remove the torn and folded debris while improving the overall surface finish.

Chris Jensen of Goodson Tools & Supplies in Winona, MN, says, "there’s a lot of confusion about how to finish cylinder bores when using diamond. Since diamond leaves a lot of folded and torn metal on the surface, the bores need to be brushed to remove the debris. Many different names are given to the same tool and process. Some call it a plateau hone, a soft hone, a whisker hone or an ultra-fine hone. But they all do the same thing: they sweep across the surface to remove jagged peaks, folded and torn material."

Bristle style soft hones consist of mono-filament strands that are extrude-molded with a fine abrasive material embedded in the strands. The filaments can be mounted in different types of holders or brushes that can be used with portable or automatic honing equipment.

When finishing the cylinders with a brush, only light pressure is required. The rpm of the brush should be similar to that which the cylinder was originally honed, and no more than 16 to 18 strokes should be applied (some say 8 to 10 strokes are about right). Too many strokes with a brush may produce too smooth a finish that doesn’t hold oil.

Reversing the direction of rotation while brushing helps to remove the unwanted material on the surface. The end result should be a cylinder that provides immediate ring seal with little if any wear on the cylinder wall or rings when the engine is first started.

Sunnen’s Mera says, "brushing the bore after honing makes a huge improvement in the surface finish, whether diamonds or conventional honing stones were used to hone the bore. You can get the overall Ra down to 8 to 12, with RPK (relative peak height) numbers in the 5 to 15 range, and RVK (relative valley depth) numbers in the 15 to 30 range."

Equipment Requirements
Something else to keep in mind about diamond is that it works best in power honing equipment that has been designed to take maximum advantage of diamond’s honing properties. There are a number of companies that make diamond honing heads for use with various honing machines: Rottler, K-Line, Kwik-Way, Peterson, Winona Van Norman, Sunnen and others. But because of the increased loads, diamond may overtax some older power honing machines and increase the risk of stripped gears. It may be better to buy a new honing machine that has more horsepower and rigidity to handle diamonds.

"Most of our customers who hone with diamonds use a CK21 machine," says Sunnen’s Mera.

As for portable honing equipment, conventional abrasives are the better choice for this type of application. Most of those we spoke with say diamonds require too much pressure for portable honing equipment.

Another difference with diamond is the type of lubricant that’s required. A synthetic water-based lubricant is usually recommended instead of honing oil.

K-Line’s van den Bergh says, "water-based lubricants are easier and cheaper to dispose of than oil-based lubricants because they can be evaporated down to reduce their bulk. On the other hand, they occasionally require make-up water and have to be monitored to prevent bacterial growth.

"The type of lubricant you choose is very important because it can make quite a difference in honing performance. With conventional abrasives, you want a good quality honing oil. A lot of people run into honing problems because they’ve diluted their honing oil or tried to use something else like diesel oil or kerosene," says van den Bergh.

Anthony Usher of Rottler Mfg. in Kent, WA, says the OEMs all use long-lasting superabrasives with metal bonded honing stones. But the equipment and controls they use are very expensive, which makes it difficult to bring the same technology into a typical aftermarket job shop.

"About 12 years ago, we decided to change that. If new engines are originally honed with diamonds, why can’t we develop the same technology? So we set about developing honing equipment, controls and stones that would put the same technology into the hands of a job shop," says Usher.

"Diamonds last a long, long time. Because the stones don’t wear away, you can control the size of the bore more accurately," Usher explains. "This allowed us to build an automatic control system that allows us to size bores exactly the same every time."

Usher says for under $30,000, a job shop can buy a diamond honing machine that substantially reduces running costs and gives better results.

"The HP6A power stroking automatic honing machine is our newest product. It runs with diamond abrasives and has a programmable load control for both rough honing and finish honing. When it is finishing the cylinder, it automatically reduces the load because some cylinders have very thin areas that may distort if the load isn’t changed. The HP6A has a base price of $23,900 and a fully equipped unit goes for $28,000 to $35,000."

Plateau Finish Is Best
Regardless of what type of honing equipment or abrasives are used to finish cylinder bores, more and more shops are finding a plateau finish provides the ultimate finish.

A plateau finish is one that closely resembles a broken-in cylinder bore. When the bore is honed, the surface of the metal will have microscopic peaks and valleys. Peaks don’t provide much ring support, so as soon as the engine is started the piston rings start to scrub up and down and shear off the tallest peaks. As the engine continues to run, the peaks will be gradually shaved down until the cylinder bores are relatively smooth and flat (except for the valleys in the crosshatch that must be there to hold oil).

The normal engine break-in procedure will eventually produce a plateau finish anyway. But until it does, the rings and cylinders will experience unnecessary wear and the engine will experience increased blowby, oil consumption and emissions until the rings have seated – which might take several hundred or even several thousand miles to complete.

A better approach is to precondition the bore surface so the rings don’t have to "hone" the cylinders. A plateau finish will provide maximum compression right from the start, and eliminate most ring seating and sealing problems.

One recipe for achieving a plateau finish is to bore or hone to within .003˝ of final size. Then finish to final dimensions with a #220 or #280 grit conventional abrasive and follow up with half a dozen strokes of a #600 grit stone, cork, or a flexible brush or nylon bristle plateau honing tool.

If diamond stones are used, bore or rough hone to within .005˝ of final size. Then hone the cylinder to final dimensions with #325 to #500 grit diamonds, followed by six to eight strokes with a flexible brush or plateau honing tool. Many experts recommend leaving a little extra metal in the bore for final finishing if diamonds have been used to rough hone the cylinder. This is because rough honing with diamond leaves a very rough finish (over 100 RA depending on the grit of stone used).

Honing Hard Materials
In recent years, Nikasil coatings have provided a challenge for engine builders. Nikasil is a hard coating of nickel and silicon carbide about .0025˝ to .003˝ thick that is applied to cylinder bores to improve wear resistance. Invented by the German firm Mahle, Nikasil was originally developed for the Mercedes Wankel rotary engine. It has been used by BMW and Porsche in some of their engines, and is also used in many chain saw engines, some motorcycle and marine engines, and even many NASCAR Winston Cup engines.

Goodson’s Jensen says PERs have had success honing Nikasil treated cylinders with diamond. But for smaller shops that have only portable honing equipment, you can’t exert enough pressure with diamond to hone Nikasil. The best advice here is to use #220 silicone carbine and just do a couple of strokes to deglaze the cylinder. If a cylinder has to be bored to oversize, cut it out with a boring bar and then hone in the usual manner to achieve the desired dimensions and finish.

Ed Kiebler of Winona Van Norman in Wichita, KS, says new harder coatings on cylinder walls are forcing shops to change to diamond honing and to upgrade their equipment.

"I see a lot of shops who are interested in diamond but who don’t fully realize what’s involved in the diamond honing process. Diamond takes a lot of pressure to cut. Some people use diamond on portable hones, but realistically you can’t get enough pressure to make the diamonds perform well. Having said that, I truly believe the new harder cylinder coating materials are going to force people to go to diamonds," says Kiebler.

"The two-cycle stuff is all Nikasil. Now the outboard engines are going to Nikasil, too. All the NASCAR Winston Cup shops are using Nikasil cylinders. If it’s good for NASCAR, it’s not going to be long before you start seeing it in OEM engines," Kiebler explains. "The time is coming when you’re going to have to use diamonds if you’re going to hone Nikasil cylinders."

Kiebler says all most shops do is slightly roughen Nikasil cylinders. "You don’t really remove much material. The Winston Cup shops are running some of these motors five races before they redo the cylinders. The Nikasil coating really extends ring life and cuts down on ring wear."

OEM TRENDS
Dave Riley of Gehring L.P. in Farmington Hills, MI, a supplier of honing equipment to original equipment manufacturers, says almost all OEM internal combustion gasoline engines in North America today are being rough honed with diamond abrasives.

Riley says the OEM focus is on using water soluble synthetic honing coolants, which means diamond abrasives because vitrified conventional abrasives require honing oil. The other industry trend he sees is that cylinder bores are being respecified to smoother finishes.

"We’re talking 0.15 to 0.3 Ra finishes that are extremely smooth," says Riley. "They’re doing this to further reduce emissions. A lot of this is being driven by ring technology because rings can now survive in conditions that provide much less oil. However, in my opinion these new surface finish specifications are reaching the limits of technology."

One of the things that the OEMs do to achieve high quality bore finishes is to use computer numerically controlled (CNC) honing machines. The cutting speeds of these machines are 50 to 75 percent faster than what was used 10 years ago. Faster cutting speeds allows the abrasives to cut smoother, and finer abrasives can be used for a smoother finish without sacrificing cycle time.

Riley says there’s a dramatic difference in the amount of time the OEMs allow to hone a cylinder versus what a typical aftermarket engine builder or production engine rebuilder spends on the same process. He says OEMs typically spend only about 15 to 20 seconds to hone a bore with automated honing equipment. By comparison, it can take up to several minutes to manually hone a bore using a power honing machine.

"The OEM machines are completely automated and automatically control bore size and shape. They also measure and inspect 100 percent of the bores, and can sort by bore size if they run bore grades," he says.

"As the need to reproduce OEM finishes in the aftermarket grows, so too will the demand for honing equipment that can meet these specifications. This will obviously have an impact on honing costs," Riley explains. "We are developing a low cost, CNC-controlled single spindle honing machine for the aftermarket. The operator would load the block and the machine would automatically hone the bores to OEM tolerances."

Riley says Gehring also offers custom honing services for low volume engine prototype development and performance engines.

Cylinder bore quality plays a huge role in reducing friction and blowby for improved engine performance and durability. Better bore geometry also contributes to better sealing and more usable power. Riley says a lot of performance engine builders are hot honing their blocks to more accurately simulate actual running conditions. They also use torque plates when honing (some with simulated manifolds to further stress the block), and may even bolt a bellhousing to the block to reproduce the stresses and loads the block will experience in a vehicle.

"For OEM production applications, we have developed clamping and other methods to stress the block while it is being honed," says Riley. This is done to further improve bore geometry and sealing.

Aluminum Engines Soon
Riley says another OEM trend is the development of future engines that use various types of bore surface coatings in aluminum blocks. The coatings are sprayed-on powder metal or steel wire alloys that create the surface characteristics of a traditional iron bore.

"Last year, about 15 percent of the prototype engines we saw had some type of coated aluminum bores. This year, the percentage is up to 67 percent. So there has been a dramatic shift toward aluminum blocks with coated bores."

Coated aluminum bores have a number of advantages, one of which is better thermal conductivity between the cylinders and water jacket. Another is less heat distortion for better sealing. The coating provides wear resistance and allows the use of larger bores within a given block size for more total displacement.

Riley says the OEMs are currently acid etching the bores to finish them. But acid is environmentally unfriendly so the OEMs are developing alternative ways to finish coated aluminum bores that do not require acid etching. Diamond honing is used for roughing, but the finishing step is being done with nonmetallic bonded abrasives such as vitrified abrasives, rubber or brushes. The goal is to come up with a process that will work using water-based honing fluid.

How will the aftermarket refinish coated bores in aluminum engines? Riley says the most likely approach will be to hone away the original bore finish, then reapply the surface coating and refinish it back to OEM specifications.

Laser Structuring
A number of years ago, Gehring developed a unique process called "laser structuring" to enhance engine durability. The process uses a laser to burn small pits into areas of the cylinder bore surface where ring loading and wear are highest. The pits improve oil retention and ring lubrication, and significantly reduces ring and bore wear.

Riley says the new laser structuring process is now being used in Europe on diesel engines. "At 150,000 kilometers, the bores are showing almost no measurable wear (only 1 to 2 microns) and the emissions performance is the same as new," he says.

Riley says the laser structuring process can be used to create almost any kind of pattern imaginable in the bore surface. Typically, a series of dots or dashes 25 to 60 microns deep and 40 microns wide are burned into the top third of the cylinder by the laser after the bore has been semi-finished. A final honing step is then done using fine stones to remove any buildup of material around the pits and to finish the bore.

The laser part of the process takes about 9 to 15 seconds per cylinder and uses a special machine that rotates and lowers the laser beam as it is projected onto the surface of each cylinder.

Riley says the laser structuring process is ideal for hard blocks or those with special surface coatings that make them difficult to finish with conventional honing techniques. "It’s a perfect application for high performance, diesel and aircraft engines," he says.

Remember To Clean The Bores
As we wrap up this article on honing abrasives, one final point to remember is the importance of cleaning the bores after honing. Honing leaves a lot of metallic and abrasive debris in the bores – which must be removed before the engine is assembled. Washing and scrubbing with warm soapy water will remove most of the loose debris. Some engine builders follow up by wiping out the cylinders with automatic transmission fluid. The point is get the cylinders clean so there are no contaminants to damage the rings or to get into the oil.



<<Side Bar>>

WHY DIAMONDS ARE SO EXPENSIVE
If you’ve balked at the high cost of diamond honing stones, here’s a brief explanation why they’re so expensive:

Diamond is a special form of carbon that is formed naturally under extreme heat and pressure deep inside the earth. As such, it isn’t very plentiful or easy to find. Subsequently, man-made synthetic diamonds are mostly used for industrial abrasives.

Scientists realized that if they could duplicate the heat and pressure that formed natural diamonds deep in the earth, they could transform ordinary graphite (another form of carbon) into diamond. They estimated it would require temperatures in excess of 6,300 degrees F and pressures of approximately one million pounds per square inch to make the transformation occur. But as the scientists discovered, it wasn’t so easy. Try as they might, they couldn’t get graphite to change its crystal structure and become diamond – until General Electric researchers discovered the secret in 1951.

A catalyst was needed to make the change happen. The catalyst turned out to be a mixture of molten iron, nickel and cobalt. The various proportions of ingredients in the catalyst are still a closely guarded secret, so only a couple of companies in the entire world have the expertise to produce synthetic diamonds. In the U.S., synthetic diamonds are produced at GE’s plant in Worthington, Ohio. Several years ago, we were given a plant tour – but nobody except a trusted few are allowed to see inside the room where the diamonds are actually made.

GE says they can create different types and sizes of synthetic diamond for various industrial purposes by varying the temperature, pressure and type of catalyst. Man-made diamonds typically have a yellowish tinge and are as small as grains of sand. Even so, they’re ideally suited for their intended use as an abrasive. They’re just as hard as natural diamonds and actually perform better because of their custom-tailored shapes and characteristics.
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
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Re: maximizing piston to bore ring seal

Postby grumpyvette » January 14th, 2011, 2:20 pm

cylinder boring tools always leaves the block bore rough so machinist always bore the bore in the block a bit under size to allow the bore to be honed out to the desired finished bore size.
the hone knocks the higher peaks into rather consistent plateaus, while retaining the groves or valleys to act as oil holding reservoirs, that keep the rings lubricated , and they also allow a place for micro fractured bits of ring and bore debris suspended in the trapped oil ,a momentary place to settle as the piston rapidly reciprocates in the bore ,until its washed away by oil splash and flow to keep the bores clean and cooled.
proper cylinder honing is critical to getting a good bore seal , and ring durability.
tightening the cylinder head and main cap bolts induce stress on the block, that distorts the block dimensions so those stresses must be duplicated during the honing process to allow the bore to duplicate its true shape, if ring seal is to be maximized.
a torque plate is used to duplicate the stress levels in the block and allow tool access while honing the block.
(1) yes youll need to have the block under stress with bolts, or studs and a torque plate to duplicate the stress on the bore walls , that a clamped cylinder head induces on the bore walls to get the hone done correctly
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BLOCKS SHOULD BE HONED TO SIZE WITH TORQUE PLATE SIMULATING HEAD BOLTS STRESS ON THE BORE WALLS

http://www.dartheadstv.com/video_detail.php?mId=13335

http://www.popularhotrodding.com/engine ... plate.html

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Any type or size of cylinder can benefit from the Flex-Hone®. These abrasive bead style brushes are produced in standard diameters from 4mm to 36”. Eight abrasive types are offered including silicon carbide, aluminum oxide, boron carbide and diamond allowing the tool to be tailored to finish any base material. A choice of 11 different grit selections are available for precise control of finish parameters. The elimination of peaks results in rapid ring seating, better oil control, reduced seepage in hydraulic and pneumatic applications and provides better seal performance and longer seal life. Successful applications include firearm chambers, shotgun barrels, musical instruments, combustion chambers, air compressors, pumps, valve bodies, valve guides, brake cylinders, wheel cylinders and the list goes on and on.

Flex-Hone® tools are also very effective for cross hole deburring, port radiusing and edge blending. Because of its unique construction, the Flex-Hone® is self-centering, self-aligning, and self-compensating for wear so it does not require an elaborate set-up or special training. Deburring with ball hones can be effectively automated and combined in the machining process to allow a complete cylinder finish in one operation or it can be employed as a secondary operation with equal results.
BRM continues to apply our years of experience and patented Flex-Hone® technology to solve difficult deburring and surface finishing problems. Our Flex-Hone® for Rotors now brings the same benefit to create the ideal surface finish on brake rotors, fly wheels and clutch plates. The tool reduces friction induced braking noises by producing a surface that lowers harmonic vibrations and creates a non-directional cross-hatch pattern. The Flex-Hone® for Rotors is more cost effective than abrasive pads and it is ideal for both new and re-turned rotors and flywheels.

http://www.dartheadstv.com/video_detail.php?mId=13335

http://www.brushresearch.com/brushes.php?c1=2

they will last for dozens of engines if used correctly but they are not real in-expensive, most cost close to $100 each
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a ball hone with 320 grit used sparingly produces a very good surface finish for moly rings to seal with but a ball hone follows the cylinder wall surface irregularities even if its a bit egg shaped or hourglass or cone shaped so its NOT going to be ideal in a well worn cylinder because the rings will not be able to fully contact a non-cylindrical cylinder wall.



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cylinder hones that use use 3-0r-4 parallel stones will tend to only remove the higher surfaces peaks but its more likely to maintain a true cylindrical surface, as the stones can,t drop into minor surface irregularities like with most tools its performance is controlled by the operator, and if its not used correctly your not going to get good results, the, hones like this need to have a constant significant flow of cooling and cleaning cutting fluid washing the fine metallic dust out of the bore/stone contact areas while its honed
http://www.circletrack.com/enginetech/c ... ewall.html


one factor I find amazing is how few guys realize that the rings MUST have space both above the ring and behind the ring in the piston grooves simply because its the hundreds of PSI of cylinder pressure that first forces the ring into the bottom of its groove then the pressure gets behind the ring and tends to expand it and hold it into the bore that is a huge factor in how effective the ring seals combustion pressure in the combustion chamber, if the clearances are filled with carbon build up the rings loose a great deal of there ability to seal.
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http://www.carcraft.com/techarticles/pi ... index.html


#525 is a 220grit hard stone & pretty coarse.
It is what I consider a "production rebuilder finish" & not what I would finish any bore with especially a performance one but it will work with cast iron or chrome
#625 is a 280grit hard stone & mid range suited to moly rings

400-500 grit stones are sometimes used after a 280 grit hone to just prep the surface briefly before final clean-up and moly ring install
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http://www.enginehones.com/lislehones.html

http://www.goodson.com/store/template/d ... 93a1b07466

http://www.wayfair.com/Lisle-Hone-Engin ... 49-IJO1028.

Ring End Gap,,, Check,,,

Failure to ensure proper ring end gap may cause the ring tips to butt, and engine damage could occur.

1. A torque plate should be attached to the engine block or cylinder (if applicable),,, and torqued to specifications.
2. Check the end gap by placing the ring into the cylinder. "The cylinder bore should be free of taper". Use the piston to square up the ring in the bore, and check the end gap by using a feeler gage.
3. See table below for proper ring end gap for your application.
4. The oil rails may be installed, by spiraling them on, without modifying the end gap. The gap should be a minimum of .010”.

Ring Gap Table Instructions,,,

1. This table is in inches. If you are measuring your bore in millimeters, you will need to convert to inches by dividing your bore size, by 25.4.
2. Multiply your inch bore size by the “Bore x” column for your application to determine the end gap.
Example: For the top ring of an ATV with a 4.0” bore, multiply 4.0" X .004" = .016"

Application,,,

Top Ring/Second Ring

Bore x
Dirt / ATV / Snow / PWC
.0040”
.0050”
High-Performance Street / Strip
.0045”
.0055”
Street-Moderate Turbo / Nitrous
.0050”
.0055”
Late Model Stock
.0050”
.0055”
Circle Track/Drag Race
.0055”
.0060”
Blown Race Only
.0065”
.0070”
Nitrous Race Only
.0070”
.0075”

Notes,,,

1. The chart above is a general guideline. Each ring should be fitted to the particular cylinder in which they are to be installed.

2. The gap on the second ring should "ALWAYS" be larger than the top ring end gap, this will help to reduce top ring flutter or lifting.

Filing Gaps,,,

1. Wiseco recommends filing ring end gaps using the proper ring end gap filing tool, either an electric ring grinding machine or manual hand crank style grinder.
2. Always file from the ring face towards the inside diameter to avoid damaging the face coating. On moly rings, the face will flake off like veneer, if pulled in the wrong direction.
3. File only one end of the ring. Use the unfiled end as a reference.
4. Be sure to keep end gaps square.
5. File until the desired end gap is achieved.
6. Remove all sharp edges and burrs, with a small pocket hone or diamond file .

Failure to remove all burrs and sharp edges could cause engine damage, by leaving lateral score marks on the cylinder wall.

Ring Installation,,,

1. Check each ring in its corresponding piston groove to ensure proper axial and radial clearance. This is important on new and used pistons.
2. Oil ring expander (the corrugated ring under the oil rails),,, place the oil ring expander into the oil groove with the butted tips of the expander 90° from either end of the wrist pin. Be sure the tips of the expander are visible and properly butted. If the expander tips are overlapped, the engine will smoke due to excessive oil use, and engine damage could occur.
3. Oil rails: The oil rails can be installed with either side up. I don't recommend using a ring expander (tool) because it has a tendency to buckle the narrow rails, instead, I spiral the rails into the oil groove, placing the first rail below the expander, and the second rail above the expander. The rail end gaps should be located at least 90° from each other. After the oil rails are installed, double check that the tips of the expander are properly butted, and not overlapped.
4. Second ring: Using a piston ring expander , install the second ring with the marked side up. An unmarked 2nd ring with an inner bevel should be installed bevel side down. If the ring is not marked on one side near the end gap, either side can be up.
5. Top ring: Using a piston ring expander, install the top ring with the marked side up. An unmarked top ring with an inner bevel should be installed bevel side up. If the ring is not marked on one side near the end gap, either side can be up.

Once again,,,

Failure to ensure proper ring end gap may cause the ring tips to butt, and engine damage could occur,,,

http://www.automedia.com/Engine_Assembl ... 100901e1/1

http://www.automedia.com/Engine_Assembl ... 100901e2/1

http://www.automedia.com/Engine_Assembl ... 101001e3/1

watch the slide show, read the links, its a fairly well done speed course in the basics
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
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Re: maximizing piston to bore ring seal

Postby grumpyvette » January 16th, 2011, 9:41 am

these instructions were included with a rebuilt engine[/color]

Break-in and Installation Instructions

PROTECT THE INVESTMENT YOU HAVE IN YOUR ENGINE.
TAKE THE TIME TO READ AND FOLLOW THESE RECOMMENDATIONS:
BREAK IN PROCEDURE
1.) Drive normally but not a continuous high speeds for the first 500 miles. Occasional quick bursts of speed followed by quick deceleration during this period, is beneficial. AVOID LUGGING!!! TRIPS AND TOWING are not recommended until after 1000 miles.

NOTE:
Applying loads to the engine for short periods of time causes increased ring pressure against cylinder walls and helps to seat the rings. This is especially important because you are "BREAKING-IN" the engine with heavy duty oils. The rapid deceleration increases vacuum and gives extra lubrication to the piston and other assemblies.
2.) IMPORTANT! AFTER 500 TO A MAXIMUM OF 1000 MILES OF SERVICE, change oil and filter and readjust the valves, except hydraulic. We also require that valve adjustments be done again after a total of 6000 miles. We require a maximum of 3000 miles between oil changes and factory recommendation on valve adjustments thereafter.

NOTE:
Add oil at 1/2 quart intervals on small capacity engines. OIL AND WATER LEVELS ARE A DRIVER OR OWNER MAINTENANCE RESPONSIBILITY, THEY MUST BE KEPT FULL. We realize that this means extra effort on your part, but it assures long and satisfactory engine performance.
3.) A heavy duty detergent oil is required. Use a good quality brand oil, Some Manufacturers require 5/30, others recommend 10/40 for 20 degrees Fahrenheit to 100 degrees Fahrenheit and use 20/50w for higher temperatures and heavy duty use.

NOTE:
In past years, it has been common practice to use non-detergent and straight weight oil during the "BREAK-IN" period because it was felt that the rings would seat quicker without the film strength additives. More recently, there has been a trend to high speed and high temperature engines, cam lobe and tappet loads also have increased to a point where it is important to use heavy duty oils which contain a EP (high pressure) additive right from the start. Rings will seat properly when moderate loads are applied as noted above in section one.
4.) Keep your engine in tune. Tune-up specifications should always be to the manufacturers recommended specifications.
5.) PLEASE! If you experience any trouble or even suspect a problem please contact us IMMEDIATELY! It is easier and cheaper to fix a little problem than a big one.


IMPORTANT ITEMS TO LOOK FOR WHEN INSTALLING
A REPLACEMENT ENGINE TO AVOID EARLY ENGINE FAILURE
1.) Determine why old engine failed. Check catalytic converter or computer controlled parts, check engine warning light codes, radiator, water pump, etc. Do not install replacement engine with defective components, this could cause premature failure.
2.) Compare rebuilt engine with old engine as to crankshaft flange, pilot hole and bearing, oil pan, timing cover, engine mounting provisions and cylinder head mounting holes.
3.) Prime the oil pump in any acceptable Industry Standard Method! This is very important.
4.) All related parts not furnished by us should be thoroughly cleaned.
5.) If original engine has blown and scattered pieces, such as piston particles, you Must thoroughly inspect intake manifold for foreign material to avoid destroying the new engine.
6.) Make sure that dipstick tube and dipstick are of proper length to register required amount of oil.
7.) Check motor mounts for oil soak and parting of rubber from metal.
8.) Radiator should be flow tested and thoroughly cleaned if necessary.
9.) Check radiator cap for application and operation.
10.) Replace thermostat to avoid possible failure.
11.) All hoses, radiator, heater, and by pass should be replaced if necessary.
12.) A heavy duty detergent oil is required. Use a good quality brand oil, Some Manufacturers require 5/30, others recommend 10/40 for 20 degrees Fahrenheit to 100 degrees Fahrenheit and use 20/50w for higher temperatures and heavy duty use.
13.) Always replace oil filter cartridge and flush any cooler lines. And replace oil cooler if contaminated.
14.) Oil pressure and temperature sending units may need to be replaced because they have a tendency to leak oil and register improper after a reinstall.
15.) Always install new spark plugs of proper heat range and check to make sure the spark plug wires are in good condition.
16.) Check distributor, advance controls and distributor cap for cracks.
17.) Water pump should be checked for signs of leaking.
18.) Clutch fan should be checked for proper operation.
19.) Fan belts should be checked for cracks and other defects.
20.) Check fuel pump for oil leak at pivot pin and also for fuel leaks.
21.) Check heat riser valve for proper operation.
22.) Replace paper air filter or clean oil type.
23.) Check smog components and computer sensors. Replace defective or old parts.
24.) VERY IMPORTANT!!!
Make sure radiator is full of coolant (at least 50% water and 50% antifreeze) and Engine Block is filled full before attempting to start engine.
CAUTION: Air Locks can ruin a new engine.
25.) When filling radiator make sure it is filled to proper capacity and that there are no air locks, as this can cause cracking of cylinder block and heads.
26.) Start engine, check oil pressure, adjust ignition timing to manufacturers specifications and adjust carburetor after engine has warmed up fully. Also, at this time be sure to check for any water or oil leaks.
27.) Take the car for a road test. After road testing the vehicle recheck installation, oil and water levels, look for any leaks, recheck timing and adjust carburetor if necessary. Please refer to "BREAK IN PROCEDURE" sheet for further information.
See Warranty Addendum #8

NOTE: After at least 1 hour running time and engine has cooled, retorque head and adjust valves to manufacturers specifications. On Required engines if you are not sure if this is required on your engine ASK!

ATTENTION: WARNING TO INSTALLING MECHANIC!!!

Every effort has been made to accurately supply the proper item, however it is the responsibility of the installing mechanic to verify engine and parts for correct size and application by comparing the old parts. This is due to the many combination's available on the market today. You are responsible for the correct installation of the engine. The engine life and performance depends on a good professional installation. Follow the instructions carefully. Seek professional help if you are uncertain about ANYTHING!
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
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Re: maximizing piston to bore ring seal

Postby Indycars » March 9th, 2011, 10:38 am

remove the burrs from the ends of the ring after gaping them, but don't round off the ring ends like the left side, in his fingers here


Hey Grumpy......I almost missed the comment above, it wasn't very close to the picture
it was referring. So with the text on the picture, nobody will get it wrong.

RingEndGapDeburring01.jpg
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Re: maximizing piston to bore ring seal

Postby grumpyvette » March 9th, 2011, 10:47 am

GREAT!
sorry if it was confusing

since youve obviously got the skill required can you point out the ends are not correctly cut ,square/parallel in this picture
Image

you generally only need to grind the tips of the expander ring (RARELY NEEDED OR DONE) or bend them only a tiny bit (PREFERRED METHOD)

Image

if at all, in most cases they come out of the packager ready to install (THERE ARE EXCEPTIONS) the expander ring should sit level in the bore , and sitting parallel with the deck with minimal tension, their job is mostly maintaining consistent space between the wiper rings, which generally use a .018 gap and allowing oil to drain back thru the groove drain slots in the piston, its the oil scraper rings not the expander that provide much of the MINIMAL tension required to keep the oil ring in contact with the bore surface
as always a call to the manufacturer is a good idea, if you have questions because different ring designs require different clearances
http://www.hastingsmfg.com/ContentData. ... ntentid=65

http://www.youtube.com/watch?v=slS8CUHRNkc

http://www.chevyhiperformance.com/tech/ ... index.html

http://www.enginebuildermag.com/Article ... rings.aspx

http://www.enginebuildermag.com/Article ... mance.aspx

http://www.hotrod.com/techarticles/engi ... ewall.html

http://www.kb-silvolite.com/assets/auto ... ctions.pdf

http://www.superchevy.com/technical/eng ... ewall.html

http://www.circletrack.com/howto/1818/index.html

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IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
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Re: maximizing piston to bore ring seal

Postby Indycars » March 9th, 2011, 11:20 am

Done !

RingEndGapNotParalla01.jpg
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Re: maximizing piston to bore ring seal

Postby grumpyvette » March 9th, 2011, 11:23 am

thank you once again for your valued efforts


BTW heres a bit more ring info

Image
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http://www.federalmogul.com/korihandboo ... ion_18.htm
Image
Rectangular Ring:
A piston ring with a rectangular cross section. This ring with its geometrically simple shape performs the necessary sealing functions under normal operating conditions. With a peripheral coating and appropriate barrel face the rectangular ring is today used mainly in the top groove in passenger car gasoline and diesel engines. Besides service in internal combustion engines, rectangular rings are commonly used as rotary shaft seals, e.g. transmission seals [1].

Taper Faced Ring:
Image
Owing to the tapered running face the ring contacts the cylinder bore with its bottom outer edge. This shortens running-in and improves oil scraping. The gas forces acting initially at the running face provide a degree of pressure relief (especially when used in the top groove). Taper faced rings are chiefly installed in the second groove in passenger car gasoline and passenger car and truck diesel engines. In passenger car gasoline engines they are also used in the top groove.

Internally Bevelled or Stepped Ring:
Image
By providing an edge relief on the top side of rectangular and taper faced rings a twist effect is achieved which, in all operating phases without gas pressure loading, brings the ring into bore contact only with its bottom outer edge while the inner edge contacts the bottom groove side (positive twist). This helps to improve oil consumption control. Under operating conditions the gas pressure forces the ring flat against the piston groove, creating an additional dynamic behaviour of the ring. Rings of this kind are used in the top and second groove of passenger car gasoline and passenger car and truck diesel engines.

Taper Faced Ring with Inside Bottom Bevel or Step:
Image
In the installed condition this edge relief causes a negative twist, i.e. in the opposite direction to a ring with the relief on the top side. The taper must be larger than on a taper faced ring without twist or with positive twist so that the top outer edge is prevented from contacting the cylinder wall.
The effect of the negative twist is to make the ring contact the groove and create a seal with its outer bottom side and its inner top side [8]. This type of ring is installed in the second groove in passenger car gasoline and passenger car and truck diesel engines.

Keystone Ring:
Image
A compression ring with a wedge cross section. With its tapered sides, radial movement of the ring in engine operation will cause the axial clearance in the groove to increase and decrease. This greatly reduces ring sticking, as the ring continuously works its way free of the combustion residues. These rings are designed with an overall side angle of 6° bzw. 15°, the larger angle being more effective against the tendency to coking. The keystone ring is used in the top groove in passenger car and truck diesel engines where ring sticking must be expected.

Half Keystone Ring:
Image
A compression ring with only the top side tapered. Like on the keystone ring, the tapered side (keystone angle 7°) causes the axial clearance to vary as the ring moves radially, and thus reduces ring sticking. Owing to its asymmetrical cross section the ring has a positive twist when installed.
A half keystone ring is used in the top groove of passenger car and truck diesel engines when a rectangular ring is no longer adequate in regard to ring sticking but a keystone ring is not yet warranted. Another application is in 2-stroke gasoline engines, e.g. for snowmobiles and ultralight aircraft.

L-Shaped Compression Ring:Image
This ring is used mainly in small 2-stroke gasoline engines as a "head land" ring, the vertical arm of the L being flush with the top edge of the piston crown [9]. With gas pressure acting behind the vertical arm, this ring will also seal when in contact with the top side of the piston groove.
Besides being used in 2-stroke engines, in some cases it has been installed in automotive diesel engines in order to minimize crevice volume in the combustion chamber [10].


related info
viewtopic.php?f=53&t=2726

viewtopic.php?f=53&t=247

viewtopic.php?f=53&t=852

viewtopic.php?f=53&t=509

viewtopic.php?f=53&t=3449

viewtopic.php?f=53&t=1797

viewtopic.php?f=51&t=1479

viewtopic.php?f=51&t=2919

viewtopic.php?f=53&t=4294
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
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Re: maximizing piston to bore ring seal

Postby grumpyvette » August 18th, 2011, 4:03 pm

DTL504 posted this info
RING END GAP CLEARANCE

The piston ring's end gap can have a significant effect on an engine's horsepower output. Rings are available both in standard gap sets, and in special "file fit" sets. The file fit sets allows the engine builder to tailor the ring end gaps to each individual cylinder. Ring gaps should be set differently dependent upon the vehicles use, within the range of .003" (for the 2nd. ring) to .004" (for the top ring) per inch of cylinder diameter. The more severe the use, the greater the required end gap (assuming the use of similar fuels and induction systems). Engines having low operating temperatures, such as those in marine applications is too small. The chart below is a general guideline for cylinders with a 4.00" bore, adjust the figures to match your engine's cylinder diameter:

Top Rings (ductile iron, 4" bore)

Supercharged

Nitromethane .022 - .024"

Alcohol .018 - .020"

Gasoline .022 - .024"

Normally Aspirated - Gasoline

Street, Moderate Performance .016 - .018"

Drag Racing, Oval Track .018 - .020"

Nitrous Oxide - Street .024 - .026"

Nitrous Oxide - Drag .032 - .034"

2nd Rings (plain iron, 4" bore)

Supercharged

Nitromethane .014 - .016"

Alcohol .012 - .014"

Gasoline .012 - .014"

Normally Aspirated - Gasoline

Street, Moderate Performance .010 - .012"

Oval Track .012 - .014"

Pro Stock, Comp. .012 - .014"

Nitrous Oxide - Street .018 - .020"

Nitrous Oxide - Drag .024 - .026"

INSTALLATION NOTES -

CYLINDER WALL FINISH

When installing new rings, the single greatest concern is the cylinder wall condition and finish. If the cylinders are not properly prepared, the rings will not be able to perform as designed. The use of a torque plate, head gasket, and corresponding bolts are necessary to simulate the stress that the cylinder head will put on the block. Main bearing caps should also be torqued in place. The correct procedure has three steps. First the cylinder is bored to approximately .003" less than the desired final size. Next it is rough honed within .0005" of the final diameter. Then a finer finish hone is used to produced the desired "plateau" wall texture. Use a 280 - 400 grit stone to finish cylinder walls for Plasma Moly rings.

Note - the "grit" number we are referring to is a measurement of roughness, it is not the manufacturers stone part number (a Sunnen CK-10 automatic hone stone set #JHU-820 is 400 grit). The cylinder bores should be thoroughly scrubbed with soap and hot water and then oiled before piston and ring installation.

Piston ring grooves are also sealing surfaces, and must be clean, smooth and free of defects. Ring side clearance, measured between the ring and the top of the groove, should be between, .001" and .004".
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
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Re: maximizing piston to bore ring seal

Postby grumpyvette » August 18th, 2011, 4:18 pm

IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
grumpyvette

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Re: maximizing piston to bore ring seal

Postby grumpyvette » October 16th, 2011, 2:55 pm

http://www.homedepot.com/h_d1/N-5yc1v/R ... ogId=10053
Image

http://www.mscdirect.com/browse/Measuri ... eler+gauge

Its critical that piston rings be measured with the piston ring riding in the bore it will function in, while the rings placed PARALLEL to the block DECK on engines where the deck is a 90 degree plane from bore center lines.(OBVIOUSLY NOT ON CHEVY (348/409)which does not have the deck at 90 degrees to the bore center line.)
Image
SO if you need a dirt cheap tool that makes it very easy to get the rings square in the bore to measure while gaping rings ... next time your in home depot and have an extra $5 get yourself one of these pvc adapter fittings, they currently cost $4.11 each and 6" of 1" pvc pipe (less than 50 cents or free scrap)
place the 1" pvc pipe on a flat surface and place the larger end of the PVC adapter balance over it so its centered , and carefully mark it with a marker then use a belt sander on the ends of the 1" pvc pipe until it just slides into the larger end of the adapter and GLUE it into place as a HANDLE
this makes a dirt cheap ring squaring tool for gaping and checking rings with the smaller end just a bit under 4" and the larger end just a bit under 4.4" perfect for about 80% of the chewy engines you'll do ring jobs on, as the small end square 4"-4.360 inch bores and the large end does 4.4"-4.6" bores... the handle must be a contact slip fit in the larger side without needing to be forced into place, because if it requires force, to get it inserted it will distort the outer plastic circumference, so its no longer round, you need to curve the 1" pvc handles end contact area on both ends, so draw a line so you index both ends correctly on the belt sander so the handle fits correctly. don,t forget to pick up a set of feeler gauges, while your there if you don,t currently have some


Image

Image
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
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Re: maximizing piston to bore ring seal

Postby Indycars » October 22nd, 2011, 3:42 pm

I liked your idea for using PVC connector to square up the rings before checking the end gap. I didn't like handling the piston 100 times while filing the rind ends. It's possible that I might drop it.

There is a 45 degree taper that keeps it from sitting flush and stable on the deck. So I had my brother cut the taper out leaving the OD at 4.12", which should just fit inside my 4.125" bore. Then I cut and rounded the ends of some 3/4" PVC that I already had for the handle. So that I could remove it, I used HOT GLUE to fix it in position.
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The ID of the big end is 4.25", since I cut the taper out, leaving an ID of 4.12 I had to be careful or I would end of with two pieces of PVC. As you can see, the LED light can be seen shinning thru the PVC.
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Re: maximizing piston to bore ring seal

Postby grumpyvette » October 22nd, 2011, 3:50 pm

not only did you do a great job making the RING SQUARE tool, as always your info posts and photographic skill is amazing
Ive been using one, of those tools for 40 plus years, they work,great and cost nearly zip, I just thought Id point out that you don,t need to spend a fortune on every tool needed, BORING and HONING a blocks bore are best done at a local machine shop where clearances and surface finish are more accurately controlled, BUT, IF your going to be honing the bores for MOLY rings I,d suggest a 240-280 grit hone a 45 degree cross hatch angle and a constant flow of flushing liquid washing over the stones and bore surface to keep the stones from clogging with micro grit trash, that gets removed from the high points in the bore surface.
Ive used both a flush of 90% diesel fuel mixed with 10% marvel mystery oil, as a flush and Ive used hot water with a couple teaspoons of dawn dish washing soap, both work, but I think the hot water and dawn solution produced the most uniform result, on the bore surface but that requires a good deal of cleaning and washing the block just like the diesel fuel mix as you darn sure want to remove all traces of grit and prevent rust forming from moisture so after hone work I power wash the block with a pressure washer,, flush the surface with alcohol paint thinner as it tends to get under and lift out micro crud and speed surface dry time ,then I spray it over with WD40 and heat it with a heat gun to remove moisture traces then re-spray it with WD, 40

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washing the blocks surface with alcohol, and drying with high pressure air helps dry a lock after a pressure washing
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Re: maximizing piston to bore ring seal

Postby Indycars » October 22nd, 2011, 4:07 pm

Thanks for the nice comments ! Your timing was great, I will be filing and setting the ring end gaps this week or next. For sure, you can't beat the price at $5.
Rick
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- Check Out My Dart SHP Engine Project: viewtopic.php?f=69&t=3814
- Need a Dynamic Compression Ratio Calculator: viewtopic.php?f=99&t=4458
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Re: maximizing piston to bore ring seal

Postby grumpyvette » November 1st, 2011, 3:54 pm

INDYCARS POSTED THESE GREAT PHOTOS
I talked with Eric at Mahle Motorsports yesterday to find out how the expander ring is suppose to work and how can I tell if the dimensions are correct.

According to Eric, there is no good way to measure this, but it should overlap about a 1/2 link when placed inside the cylinder. It's suppose to be bigger than the cylinder bore in it's free state. When you put the 2 oil rails plus the expander in the piston groove and then compress the oil rails it will compress the expander, making it's diameter smaller such that it does NOT contact the bore.

This is where very careful observation of these components is critical. The two oil rails MUST contact the shoulder on the expander. The expander ENDS must NOT overlap, rather the two ends must butt-up against each other or the oil rails will NOT do their job because they will lack the force needed against the cylinder wall to seal properly and control the oil. Don't get this right and your motor is going to smoke badly.


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IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
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