piston rings & related info

[grumpyvette]

step ONE
if the bores not concentric, and bore walls parallel and the bore surface consistent in its surface Finish or if you had the bore honed without the use of torque plates simulating a cylinder heads bolted in place, the rings WILL NOT SEAL as effectively , as they would if you had prepped the bores correctly or won,t seal effectively at all.
BEFORE you select any piston rings for any application, you obviously must know your bore diameter, and piston ring groove sizes, so check with the manufacturer to verify they will work in YOUR application,some of the 1/16" top compression rings are designed for limited mileage and race use , where they are replaced fairly regularly, thats certainly not true of all 1/16" rings but its potentially an issue on a street driven car.
be aware that rings have a top and bottom side , and must be installed with the proper side facing the top of the piston, and rings require a certain back and end gap clearance.


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READ THE LINKS BELOW

viewtopic.php?f=51&t=588&p=4946&hilit=honing+plate#p4946

http://www.totalseal.com/pdf/ts_rings_article.pdf

http://www.kb-silvolite.com/news.php?ac ... ad&N_id=27

http://www.connectingrods.net/connectin ... tretch.php

viewtopic.php?f=53&t=1797&p=7233&hilit=cleaning+piston+groove#p7233

viewtopic.php?f=53&t=3759

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

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

http://www.aa1car.com/library/honing98.htm

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

viewtopic.php?f=53&t=1797&p=4586#p4586

http://www.rosspistons.com/information/index.php

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

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

http://www.aa1car.com/library/ar293.htm

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

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

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

http://www.stockcarracing.com/techartic ... index.html

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

http://www.carcraft.com/techarticles/pi ... index.html

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

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

http://www.stockcarracing.com/techartic ... index.html





piston rings move both in and out of the piston grooves and rotate as the piston moves thru its 360 degree rotation, keep in mind its the ring groove SPACING, and gap indexing and relationship to the rings, that is designed to minimize the loss of cylinder pressure thru the ring gaps, thats key, here, not where the gaps are exactly located , because the fact is that piston rings do tend to rotate in the piston groves in most engines, and its rare to find the ring gaps in the same location once the engines been run for several hours. Id also point out that failure to have the bore honed with the correct deck plates tends to reduce the ring seal. in fact having the rings rotate in the piston grooves tends to reduce bore wear, and keep the grooves clearance free from carbon build up







if you have oil ring expanders with the plastic bits,they are there to prevent you from over lapping the ends of the oil ring expander, theres some oil ring expander s that are vertical ,some horizontal, but all have the ends butt , none over-lap
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
IVE used the TOTAL SEAL GAPLESS RINGS in a few engines Ive yet to see any huge improvement over standard rings in either durability or power produced




gapless ring




install gapless rings with the wrong side facing up and youll have an oil burning disaster (yeah! Ive got friends that never read instructions too!)


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

your going to need decent feeler gauges




now years ago, we were instructed to leave the second ring gap at a tighter .004 per inch of bore with the upper top ring having the larger end gap due to the higher heat levels, it operates under ,well extensive testing in recent years shows that
(1)the second ring gap needs to be larger because if significant cylinder pressure builds between the top and lower ring the upper ring seal is quickly lost
(2)theres very little cylinder pressure lost thru the ring gaps in the thousandths of a second the rings are compressing the fuel/air mix, or during the power stroke, because most of the blow by, is the result of less than effective ring to cylinder wall seal
(3) ring seal is destroyed if the ring gap allows the rings to contact, or the rings butting destroys the piston lands
(4) ring gaps up to about .045 have very little effect on blow by or oil use

http://www.kb-silvolite.com/article.php ... ad&A_id=64
Application

Bore x
High-Performance Street / Strip
.0045”Top Ring
.0055”2nd Ring
Street-Moderate Turbo / Nitrous
.0050”Top Ring
.0055”2nd Ring
Late Model Stock
.0050”Top Ring
.0055”2nd Ring
Circle Track/Drag Race
.0055”Top Ring
.0060”2nd Ring
Blown Race Only
.0065”Top Ring
.0070”2nd Ring
Nitrous Race Only
.0070”Top Ring
.0075”2nd Ring


types of piston dome configurations


btw heres typical detonation damage, and in this case, resulting from a bit of nitrous, that boosted the pressure, but the results would be similar on a high compression engine subjected to crappy fuel and high loads at high rpms without nitrous, notice the sugary/frosted appearance and rounded edges of the melted areas



damage to the ring lands can be caused by detonation or just the ring gaps set too tightly, if the piston shows no frosted appearance its usually the ring gaps too small, or excessive heat, to lean a mix, to much ignition advance,etc.

[grumpyvette]

http://www.probeindustries.com/Chevy_38 ... p3832f.htm]Probe website

look closely at the connecting rods one edge of the main bearing are is beveled noticeably more than the other that beveled side faces away from the rod its paired with because it matches the slight radiased bevel of the crank journal
many builder class pistons are designed to go in, in either orientation ,and have both the valve notches and piston pin offset that are identical but most performance pistons have a dot or an F stamped on the crown indicating the side facing the front of the engine, naturally the rod big end bevels face the crank counter weights on each pair and the non-beveled big end faces the matched rod

http://www.kb-silvolite.com/assets/kb_installation.pdf
when in doubt call the PISTON manufacturer and ASK!

look thru these links

http://www.federalmogul.com/korihandboo ... ion_18.htm

http://www.grantpistonrings.com/catalog ... _Types.pdf

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READ THIS THREAD
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raceman6135 posted this additional info

"Offset wrist pins"

The above info is listed on the Probe website for piston P3832F. "Offset wrist pins" means that there will be 'left' and 'right' bank pistons.

As Grumpy mentioned, there will be some indication on the piston as to its orientation in the block. Here are some pix of pistons which use notches, dots, or arrows:










hastings PH#
800-776-1088

total seal
(623) 587-7400
Ive used several sets of total seal gapless rings in several engine builds over the years, they usually have a slightly better leak down test result , but I can,t really see and measurable power or durability increase
anytime you need info , like if you mix up the rings or need install info

STOP


call the manufacturer to verify
dots face up
the top ring is usually the one with the inner bevel is the top ring with the bevel facing up



when you gap the rings don,t forget to de-burr the end gap but DON,T excessively bevel the end like the end in this guys fingers


ends must match with no angles/gaps


gaps should be about .0045 per inch of bore diam.
example a 4.25" bore should have a 4.25x .0045 end gap or a 19-20 thou end gap



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 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.