bearing clearances

[grumpyvette]

Rod bearings 0.002 - 0.025" , side clearance 0.010 - 0.020"

Main bearings 0.002 - 0.003" for most engines ( 0.020-0.025 bearing clearance on small blocks, .025-.027 bearing clearance is about ideal, on big blocks ), 0.005 - 0.007 crankshaft end play

Piston to head clearance 0.038 MINIMUM including gasket (.038-.042 quench is what you want with steel rods)(steel rods), 0.060" MINIMUM quench aluminum rods

Valve to piston clearance MINIMUM 0.100" exhaust , 0.080" intake NO VALVE FLOAT
Recommended: 0.080 intake, 0.100 Exhaust (steel rods) 0.100 intake, 0.120 Exhaust aluminum rods
TORQUE SPECS CAN BE FOUND HERE IN THIS LINK
viewtopic.php?f=50&t=1222
watch this video




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

https://www.youtube.com/watch?v=pmTyOza5-po

https://www.fordmuscle.com/fundamentals/plastiguage/

viewtopic.php?f=59&t=1026&p=4327&hilit=plasti+gauge#p4327

viewtopic.php?f=53&t=2726&p=7077&hilit=plastigauge#p7077

http://www.autozone.com/test-scan-and-s ... 36168_0_0/

http://www.hotrod.com/how-to/additional ... icrometer/

viewtopic.php?f=53&t=9214&p=43456&hilit=plastigauge#p43456
http://video.answers.com/engine-bearing ... s-39414874

http://www.summitracing.com/parts/MEL-10990/?rtype=4

http://www.engineparts.com/techbulletin ... 1-205R.pdf

http://www.stealth316.com/misc/clevite- ... ooving.pdf

viewtopic.php?f=53&t=852&p=21611#p21611

http://www.circletrack.com/enginetech/c ... ce_basics/

viewtopic.php?f=53&t=10213

http://www.vsihp.com/library/CleviteEng ... sGuide.pdf

http://www.bracketracer.com/engine/mains/mains.htm
http://cleviteonengine.com/askclevite.asp

http://www.jegs.com/p/Clevite/Clevite-7 ... 4/10002/-1


viewtopic.php?f=50&t=1222



http://ecatalog.mitutoyo.com/Holtest-Ty ... C1530.aspx


Rod bearings 0.002 - 0.025" , side clearance 0.010 - 0.020"

Main bearings 0.002 - 0.003" for most engines ( 0.020-0.025 bearing clearance on small blocks, .025-.027 bearing clearance is about ideal, on big blocks ), 0.005 - 0.007 crankshaft end play

Stock Bearing Clearances

The general rule of thumb for bearing clearances is 0.0010 inch for every 1 inch of journal diameter. That's true for mains and rods, and applies to almost all engines. For the small-block's 2-inch rod journals, that means 0.002 inch of clearance between the rod journal and bearing, by the rule of thumb. The GM-specified tolerances are 0.002 to 0.0025 inch, which lines up well with the rule. Side clearances come in at 0.010 to 0.020 inch, as specified by GM. The clearance rule applies to most engines, but it's generally best to avoid going below 0.0020 inch on any bearing, regardless of the journal diameter.

YOU ALSO HAVE THE OPTION OF HAVING THE CRANK JOURNALS MICRO POLISHED WHILE REMOVING JUST ENOUGH SURFACE FROM THOSE JOURNALS TO GAIN THE REQUIRED CLEARANCE, IF THE CLEARANCE IS TOO TIGHT

viewtopic.php?f=53&t=9955&p=38385&hilit=crank+journal#p38385

viewtopic.php?f=53&t=9214&p=33116&hilit=crank+journal#p33116

WATCH VIDEO most larger machine shops can do that cheaply and gain you the required clearance
http://www.youtube.com/watch?v=mHVzyvszbhw
Influence of Grooved Main Bearings on Performance


Manufacturers are frequently asked what difference grooving makes. Various forms of main bearing grooving have been used over the years.


It’s essential to understand that bearings depend on a film of oil to keep them separated from the shaft surface. This oil film is developed by shaft rotation. As the shaft rotates it pulls oil into the loaded area of the bearing and rides up on this film much like a tire hydroplaning on wet pavement.

Grooving in a bearing acts like tread in a tire to break up the oil film. While you want your tires to grip the road, you don’t want your bearings to grip the shaft, so grooving is bad for maintaining an oil film. The primary reason for having any grooving in a main bearing is to provide oil to the connecting rods. Without rod bearings to feed, a simple oil hole would be sufficient to lubricate a main bearing.

Many early engines used full grooved bearings and some even used multiple grooves. Those choices were based on what engineers knew at the time. As engine and bearing technology developed, the negative effect of grooving was recognized and bearing grooving was removed from modern lower main bearings. The result is in a thicker film of oil for the shaft to ride on.

This provides a greater safety margin and improved bearing life. Upper main shells, which see lower loads than the lowers, and hence don’t apply the same load to the oil film, have retained a groove to supply the connecting rods with oil.

In an effort to develop the best possible main bearing designs for high performance engines, manufacturers have investigated the effects of main bearing grooving on bearing performance. The graphs (Figure 1) illustrate that a simple 180° groove in the upper main shell is still the best overall design.

While a slightly shorter groove of 140° provides a marginal gain, most of the benefit is to the upper shell, which doesn’t need improvement. On the other hand, extending the groove into the lower half, even as little as 20° at each parting line (220° in total), takes away from upper bearing performance without providing any benefit to the lower half. It’s also interesting to note that as groove length increases so does horsepower loss and peak oil film pressure, which is transmitted directly to the bearing.

Notes: You will still find some full-grooved main sets offered for older engines where demand is low and the engineering cost to bring the sets to current standards is not warranted (bearings generally represent the technology of the time the engine was developed).

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

http://www.goodson.com/store/template/p ... f3f1075a76

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

http://www.circletrack.com/tipstricks/4 ... index.html

http://www.carcraft.com/techarticles/cc ... _tips.html

viewtopic.php?f=53&t=88&p=112#p112

viewtopic.php?f=50&t=10363

viewtopic.php?f=53&t=1916

viewtopic.php?f=50&t=499&p=617&hilit=plastigauge#p617

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


http://www.engineparts.com/techbulletin ... 1-205R.pdf








http://www.carbideselect.com/burshpescuts.php
Ive generally found the H-series bearings are the best choice, remember most after market cranks have beveled crank journals requiring matched beveled edge (H) style bearing inserts, standard bearings will have the edge of the bearing insert bind on the radias edge



in a properly set up block a pressurized oil film supports the cam and main bearings
http://carcraft.automotive.com/66890/cc ... -tips.html




bearings AND connecting rods have an inner facing side and outer side the inner side facing the matching rod has far less edge clearance because they don,t need the radias that is required for the edge of the crank journals
IVE dunked my piston/ring assembly's in a can of MARVEL MYSTERY OIL just before installation with a ring compressor and have never seen the slightest indication of problems either on ring sealing getting the rings broken in, or on tearing the engines down later for inspections the amounts not that great, ideally each one installed adds a bit of resistance but at no time should the short block take over 40 ft lbs ABSOLUTE MAXIMUM to start it spinning,and LESS than 20 lbs to keep it moving, even with all the rings and pistons installed,yes you need to verify the bearing clearances during assembly and IT SHOULD take between 20lbs-25 lbs to start it spinning if the clearances are correct! and LESS than 20 lbs to keep it moving
IF it takes over 40 ft lbs to get it rotating ,youll need too DISASSEMBLE and FIND OUT WHY!

when you get the crank polished take the time and effort to clean out any cross drill oil feed passages and to very carefully de-burr the passage opening edges, as this is a very commonly overlooked issue, below is what at first looks like a perfectly polished crank, with oil feed passages to the rod bearings, but the deep scratches the oil feed passage openings left in the rod bearing surfaces bare witness, after a single rotation, during a trial assembly show they are HARDLY burr free or ready for use, and obviously he failed to check each rod bearing during the assembly process, and probably ignored , what was very likely un-even or rather excessive resistance to the crank rotation. which should never exceed about 40 ft lbs even with all 8 rod bearings and pistons installed


having the correct bearing clearances are critical, to durability, generally you'll want no less than .0022-.0025 with .0025-.0028 preferred for most performance use. I prefer .0025-.0028 most of the time
Both rods & mains.
Bearing Tips And Tricks
1. Always check your micrometer with a standard before measuring.

2. Always use the same micrometer for the journals and to set the inside mic diameter.

3. Torque the rods and mains to spec before measuring a bearing inside diameter.

4. Changing rod bolts or moving from bolts to studs in the main caps will affect bearing clearance.

5. Temperature will affect the accuracy of the micrometer and the size of journal diameters both inside and out.

6. If you have one tight and one loose rod-bearing combination, try switching the bearings between the two. We've seen this work several times when the clearances are just a little bit off.

7. Never mix different bearing families when customizing bearing clearance. If you are using Federal-Mogul coated bearings, don't mix in a half shell uncoated race bearing.

http://www.robertpowersmotorsports.com/Tech2.html

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

http://mechdb.com/index.php/Plastigagin ... clearances

from chevy high performance mag
MORE USEFUL INFO

BE 100% SURE that the oil pump bolt or STUD doesn,t protrude past the inner main cap surface , because if it bears on the rear main bearing shell it will almost always result in a quickly failed rear bearing

failure to use the correct stud, bolt or nut or check clearances when mounting an oil pump can cause problems


ONE RATHER COMMON MISTAKE IS USING THE WRONG OIL PUMP STUD OR BOLT TO MOUNT THE OIL PUMP AS IF EITHER EXTENDS THRU THE REAR MAIN CAP IT CAN AND WILL BIND ON THE BEARING AND LOCK OR RESTRICT, SMOOTH ROTATION




viewtopic.php?f=54&t=4580
watch this video
http://www.summitracing.com/parts/MEL-10778/?rtype=4



use plasti-gauge across the whole bearing as you can have a tapered journal thats correct in one area but loose or tight else-ware



GROOVE the edge of the bearing in the area marked in green as it provides extra lubrication to the bearing where its needed most(the rear support face) that resists the pressure from the clutch and or/torque converter
notice the bearing wears near the edge during the test fit indicating either the bearing is tapered or the bearing or main caps not seated correctly, in any case stop and find out whats causing the problem


failure to clean out the oil passages in the block and crank journal cross feed oil holes, resulted in trapped debris being flushed out and scoring the bearings during the test fit process in these bearings, an easily avoided but very common screw-up after a cam or bearing fails and your forced to do a ring, cam,lifter, and bearing replacement
just keep in mind that you'll need to very carefully blend and smooth and carefully clean,the edges of the beveled area where the oil port feeds the bearing surface with some 600 grit sand paper so the oil flows well and theres no edges to cause bearing wear issues or crud left from the process that would get embedded in the bearings.



watch this video
http://www.youtube.com/watch?feature=pl ... dEFGJqpCMY

http://www.jensenhealey.com/tech/plasti ... gauge.html

Rod bearings 0.002 - 0.025" , side clearance 0.010 - 0.020"

Main bearings 0.002 - 0.003" for most engines ( 0.020-0.025 bearing clearance on small blocks, .025-.027 bearing clearance is about ideal, on big blocks ), 0.005 - 0.007 crankshaft end play

Piston to head clearance 0.038 MINIMUM including gasket (.038-.042 quench is what you want with steel rods)(steel rods), 0.060" MINIMUM quench aluminum rods

Valve to piston clearance MINIMUM 0.100" exhaust , 0.080" intake NO VALVE FLOAT
Recommended: 0.080 intake, 0.100 Exhaust (steel rods) 0.100 intake, 0.120 Exhaust aluminum rods
TORQUE SPECS CAN BE FOUND HERE IN THIS LINK
viewtopic.php?f=50&t=1222

re- check with plasti-gauge during the pre assembly

btw spray the bearing and the crank surfaces, and the plasti-gauge with WD40 before you measure clearances and it won,t tend to stick as much


http://www.goodson.com/store/template/p ... f3f1075a76
Clevite H-Series main bearings were developed primarily for NASCAR racing, but are well suited to other types of competition engines as well. They're especially good for engines that run at medium-to-high revs. They have steel backings with carefully selected overlays and a high crush factor, plus a medium level of eccentricity. H-Series bearings have enlarged chamfers at the sides for greater crank-fillet clearance and are made without flash plating for better seating. They're also available with either 180 degree or 360 degree oil grooves, as well as an extra 0.001 in. of clearance. the 180 degree groove bearing with only the top 1/2 groove in the block is preferred as having the lower 1/2 in the main cap without the groove, has a higher load capacity






LOOK CLOSELY the upper main bearing, that seats in the block, is grooved the lower half that seats in the main cap is NOT GROOVED


HERES A GREAT DEAL OF INTERESTING RELATED INFO

viewtopic.php?f=53&t=619&p=10925&hilit=bearings#p10925

viewtopic.php?f=53&t=5478

viewtopic.php?f=54&t=3519&hilit=bearings

viewtopic.php?f=54&t=3834&p=10199&hilit=bearings#p10199

viewtopic.php?f=53&t=3449&p=9293&hilit=bearings#p9293

viewtopic.php?f=54&t=2187&p=9097&hilit=bearings#p9097

http://engineparts.com/techbulletins/CL77-1-205R.pdf

viewtopic.php?f=53&t=247&p=8348&hilit=bearings#p8348

viewtopic.php?f=51&t=1479&p=7446&hilit=bearings#p7446

viewtopic.php?f=53&t=2727&p=7078&hilit=bearings#p7078

viewtopic.php?f=53&t=2351&p=6453&hilit=bearings#p6453

viewtopic.php?f=53&t=88&p=5709&hilit=bearings#p5709

[IBob]

Do you consider a rod vise necessary for torquing rods to measure inside bearing size or would a couple pieces of 1/4-1/2" thick aluminum in a bench vise be ok?

[grumpyvette]

the large shop bench vise works ok,
Ive used two 6" x 3" sections of hard plastic cut from a cutting board, you can buy at most large department stores for under $12 to pad the vise jaws
and protect and support the rods, while I do minor clearance checks and polish work, for several years,
but keep in mind I generally don,t use anything but the cap screw rod designs with full float piston pins in most engines I build, like these top two pictures below as it costs more and takes longer to polish and re-size stock rods, and you find you spend a great deal of effort on inferior rods compared to the SCAT,EAGLE, OLIVER, CROWER, or even SUMMIT RODS THAT CAN BE 200% or MORE stronger and cost in the $300-$500 range , you might be amazed at the deals available at times, Ive purchased OLIVER connecting rods off Craigs list for $250 a set new in the box from guys who are getting out of racing, divorced etc.




one of these board can be cut to form really great jaw pads on a clamp or rod vise

http://www.google.com/products/catalog? ... JsBEPICMAU

http://www.tapplastics.com/shop/product ... 5278680425

http://www.butcher-packer.com/index.php ... 4fd5491929

but very seldom


http://www.kmart.com/shc/s/p_10151_1010 ... 926x00003a

http://www.summitracing.com/parts/SME-906006/

http://www.summitracing.com/parts/PRO-66769/

and while rod vises are not all that expensive they don,t get used all that frequently unless you deal with stock style rods

http://www.youtube.com/watch?v=oG9xF5EjEz0
read this




viewtopic.php?f=53&t=1110

viewtopic.php?f=53&t=140

viewtopic.php?f=53&t=106

[IBob]

Thank you, Sir.

[grumpyvette]

http://mahleclevite.com/publications/EB-10-07.pdf

For technical service call:
1-800-248-9606

CLEVITE CATALOG

http://www.kingbearings.com/ecatalog.php

KING BEARINGS










[img]http://www.grumpysperformance.com/bearinghh4.jpg[/img





Even with roller valve train there is a break in period where the metals have to "mate". on flat tappet valve trains and non-roller rocker valve trains use of a good moly assembly lube is critical, Break in oils and assembly lubes have high pressure additives to help protect these new surfaces while this "mating" is taking place. Regular motor oil does not, always have the required additives or enough of them. thus using a good moly based assembly lube on lifters and bearings helps reduce wear , on roller rockers and roller lifter a mix of 50% assembly lube and 50% MARVEL MYSTERY OIL, thins this moly mix viscosity allowing it to penetrate roller bearings far faster

[grumpyvette]

keep in mind while your assembling the components for your engine that its usually a good idea to buy a complete matched rotating assembly from a single manufacturer, Ive used G.M. forged and SCAT forged components for decades, cast cranks and MANY stock rods are not designed to be used under race stress levels, the OME blocks, are not designed for those stress levels either. its the quality of the machine work and balancing plus attention to details like bearing clearances and the damper used that has a HUGE effect on durability , Ive built dozens of engines with SCAT cranks both CAST STEEL and 4340 FORGED STEEL, with ZERO issues.
the mere fact that there is a problem, encountered with bearing clearances, while checking with micrometers or plastic-gauge, or excess resistance to rotation or a clearance issue found with the rotating assembly components or of needing excess force to spin the engine indicates MAJOR assembly issues, that must be corrected before you proceed further with assembly.
the links posted go into most of the potential things that need to be checked BEFORE, and During the assembly process.
Even a forged 4340 crank will quickly fail if you don,t balance and assemble an engine with those factors set up correctly,and the FACT is that a forged steel or CAST STEEL crank is made of stronger material than a cast iron crank, thats not in dispute, its the engine builder thats responsible to make sure the clearance work, , parts selection,and balance work and parts matching process is correctly completed.
get cheap, assemble a random bunch of miss matched components , forget to do the clearance work, install a damper thats not correct and ANY crank assembly will eventually fail.
theres a reason why a forged crank is usually selected for a race engine, its FAR MORE DURABLE
why cast cranks and high stress and high rpms are a bad idea
and NO! THESE ARE PICTURES OFF THE INTERNET, IVE NEVER BUSTED A CRANK, BUT I AM AWARE IT HAPPENS and TEND TO AVOID USE OF CAST IRON CRANKS, OR STOCK CONNECTING RODS IN RACE APPLICATIONS





RELATED INFO

viewtopic.php?f=53&t=852

viewtopic.php?f=53&t=204

viewtopic.php?f=53&t=852

viewtopic.php?f=53&t=247

viewtopic.php?f=53&t=2726

viewtopic.php?f=52&t=399

viewtopic.php?f=52&t=181

viewtopic.php?f=53&t=3554

viewtopic.php?f=53&t=341

viewtopic.php?f=44&t=38

viewtopic.php?f=69&t=5123

[grumpyvette]

"hey grumpy?
The machine shopI used said the crank I brought them, needed to be turned down and re-polished, the guy who turned the crank said they turned it 10/10, so I bought 10/10 bearings. BUT The crank was already 10/10,when I bought it, the shop didn't mean to say it was an additional .010, do you think?, well I assembled the engine and Ive got 5PSI at idle and only 7 psi once its up at 2000rpm so I shut it off and checked, the rods seem to have a good deal of side too side clearance,now what?"


your certainly NOT the first guy to take a machine shops word on the bearing clearances, only to find out that your info was either WRONG or you miss-understood what was said, thats why YOU MUST check each and every bearing clearance, rod side clearance, valve train clearance, rotating assembly and oil pump clearance, deck clearance, ETC.! and rocker geometry measurement in the engine during the assembly process.
I know several guys that took a machine shops "WORD" as the truth on machine work BEFORE they had problems, who will NEVER AGAIN assume machine shops do things correctly, I know I got screwed a couple times by machine shops when I was much younger, before I learned that PEOPLE MAKE MISTAKES and MANY MACHINE SHOP PERSONNEL, just don,t do quality work, so your forced to verify clearance yourself

heres some threads youll want to read thru before re-assembly...
yes it could take you all day to read these threads and sub links,
but it could save you hundreds of dollars and a bunch of cash,
so its well worth the effort


viewtopic.php?f=53&t=852

viewtopic.php?f=53&t=5478

viewtopic.php?f=53&t=247

viewtopic.php?f=53&t=6926

viewtopic.php?f=53&t=6352

viewtopic.php?f=53&t=619

viewtopic.php?f=53&t=509

viewtopic.php?f=53&t=4419

viewtopic.php?f=53&t=3449

viewtopic.php?f=53&t=1478

viewtopic.php?f=54&t=1800

viewtopic.php?f=53&t=1138

viewtopic.php?f=50&t=7604&p=25728&hilit=side+clearance#p25728

viewtopic.php?f=50&t=4946&p=13685&hilit=plastigauge#p13685

[grumpyvette]

heres a few links worth reading thru

MEASURE CAREFULLY

When refinished, the surface of a crankshaft will develop microscopic peaks which are “tipped” in the direction that the sparks spray during grinding (see the illustration above). If these peaks point toward the oil film area when the engine is running, lubrication is interrupted, and the bearing will show premature wear. It is important that the crankshaft be ground and final polished so that these peaks are tipped opposite the direction that the crank rotates when it is installed in the engine, this is referred to as the “favorable” direction. We recommend grinding the crank in the “favorable” direction, followed by a multi-step polishing process using progressively finer paper. The first polishing operation uses 280 grit paper with the shaft rotating in the reverse direction – this helps to “knock off” some of the raised material left over from grinding. The second polishing process uses 320 grit paper, and the crank should be rotating in the “favorable” direction. A third step polish with a very fine (400 grit) paper is optional, but should again be done in the “favorable” direction. If the thrust surface was contacted during the resizing operation it must also be polished.

HERES WHAT A MACHINE SHOP CRANK POLISHING BELT LOOKS LIKE


care must be taken to ensure the journal does not get polished unevenly, tapered or egg shaped

journal surface must be polished so micro burrs face away from the direction of rotation on bearing surface for max durability on bearing surface, burrs far to small too see or feel still induce wear



http://www.kingbearings.com/files/Engin ... d_Them.pdf

http://www.kingbearings.com/files/Engin ... y_Work.pdf

http://www.kingbearings.com/files/Geome ... arings.pdf

[grumpyvette]

"grumpy do you bother to dunk the piston in oil or do you just oil the rings before installing pistons in the block?"

read thru these links theres a bit more involved that stuffing a well oiled piston in the block.
http://forum.grumpysperformance.com/viewtopic.php?f=53&t=852

http://forum.grumpysperformance.com/viewtopic.php?f=53&t=247

http://forum.grumpysperformance.com/viewtopic.php?f=53&t=4630

http://forum.grumpysperformance.com/viewtopic.php?f=53&t=509

http://forum.grumpysperformance.com/viewtopic.php?f=53&t=3897&p=10316&hilit=ring+compressor#p10316

Influence of Grooved Main Bearings on Performance
http://www.enginebuildermag.com/Article ... mance.aspx

Manufacturers are frequently asked what difference grooving makes. Various forms of main bearing grooving have been used over the years.


It’s essential to understand that bearings depend on a film of oil to keep them separated from the shaft surface. This oil film is developed by shaft rotation. As the shaft rotates it pulls oil into the loaded area of the bearing and rides up on this film much like a tire hydroplaning on wet pavement.

Grooving in a bearing acts like tread in a tire to break up the oil film. While you want your tires to grip the road, you don’t want your bearings to grip the shaft, so grooving is bad for maintaining an oil film. The primary reason for having any grooving in a main bearing is to provide oil to the connecting rods. Without rod bearings to feed, a simple oil hole would be sufficient to lubricate a main bearing.

Many early engines used full grooved bearings and some even used multiple grooves. Those choices were based on what engineers knew at the time. As engine and bearing technology developed, the negative effect of grooving was recognized and bearing grooving was removed from modern lower main bearings. The result is in a thicker film of oil for the shaft to ride on.

This provides a greater safety margin and improved bearing life. Upper main shells, which see lower loads than the lowers, and hence don’t apply the same load to the oil film, have retained a groove to supply the connecting rods with oil.

In an effort to develop the best possible main bearing designs for high performance engines, manufacturers have investigated the effects of main bearing grooving on bearing performance. The graphs (Figure 1) illustrate that a simple 180° groove in the upper main shell is still the best overall design.

While a slightly shorter groove of 140° provides a marginal gain, most of the benefit is to the upper shell, which doesn’t need improvement. On the other hand, extending the groove into the lower half, even as little as 20° at each parting line (220° in total), takes away from upper bearing performance without providing any benefit to the lower half. It’s also interesting to note that as groove length increases so does horsepower loss and peak oil film pressure, which is transmitted directly to the bearing.

Notes: You will still find some full-grooved main sets offered for older engines where demand is low and the engineering cost to bring the sets to current standards is not warranted (bearings generally represent the technology of the time the engine was developed).






A FEW VIDEOS TO HELP YOUR ASSEMBLY

http://www.youtube.com/watch?v=eSxjI6BxgpI

http://www.youtube.com/watch?v=PXFT4ShDryk

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

http://www.youtube.com/watch?v=rXp1vVtsp7s

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

http://www.youtube.com/watch?v=r1PO26ZqUEs

http://www.youtube.com/watch?v=sQhNIiPyTB4

http://www.youtube.com/watch?v=iuj9nfQ-LRY

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

http://www.youtube.com/watch?v=ypQwgm1H2NU

http://www.youtube.com/watch?v=-VwsbEg7Z4I

http://www.youtube.com/watch?v=bcMuttJ9RFc

http://www.youtube.com/watch?v=1LcYEZwOIQQ

[87vette81big]

Grumpy,

Can You give more insight on the Bearing oil running clearance shown above ?
What size or diameter of mains & rods used.
What make of engine ?
What weight of oil used?
Graphs shown do they show entire oil engine flow requirements ?
Or just a Single main bearing journal ?
Read through 1/2 of your links.
Only so much time to read each day lately.
Been non stop busy.
Read & post from my phone when have a few moments.

Pontiac & Olds V8 engines are similar but my different from Chevys in regards to oiling system.
Been a long habit of mine to check & measure all with Calibrated micrometers & Sunnen Dial Bore Gauges.
Set up to .0001 or within 1/10,000 desired main & rod bearing runners oil clearances.
All bearings lap in during break in
I account for extra bearing to crank clearance after break in.

[87vette81big]

Thanks Grumpy !

Brian R.

[grumpyvette]

as Im sure your aware I take the more interesting or potentially instructive questions I answer on other sires and cut and paste them on this sites to add data to this sites library of useful info.
that question
"grumpy do you bother to dunk the piston in oil or do you just oil the rings before installing pistons in the block?"
came with very little extra info so I answered it as best as I could, below,



read thru these links theres a bit more involved that stuffing a well oiled piston in the block.
http://forum.grumpysperformance.com/viewtopic.php?f=53&t=852

http://forum.grumpysperformance.com/viewtopic.php?f=53&t=247

http://forum.grumpysperformance.com/viewtopic.php?f=53&t=4630

http://forum.grumpysperformance.com/viewtopic.php?f=53&t=509

http://forum.grumpysperformance.com/viewtopic.php?f=53&t=3897&p=10316&hilit=ring+compressor#p10316

[bytor]

Huh, this is interesting. I missed this when studying for my build. Don't most small block bearings come with only one half that has the groove in it? It makes since though.

bearinghh6.jpg

[grumpyvette]

http://www.stealth316.com/misc/clevite- ... ooving.pdf

http://stealth316.com/misc/clevite-77-r ... arings.pdf

http://kingbearings.com/files/Engine_Be ... erials.pdf



you might keep in mind bearing manufacturers are in business to sell bearings and if a small but consistent segment insists on buying and paying for 270 and 360 degree bearings the manufacturers will supply that demand to make a profit, they will also post tech bulletins explaining why a 180- degree oil feed groove in only the upper bearing shell provides a more durable bearing that carries more load capacity

heres a quote from a bearing manufacturer
extending the main bearing groove much past 180 degrees increases friction, reduces load capacity costing hp, read the link
"Influence of Grooving on Main Bearing Performance
Various forms of main bearing grooving have been used over the years. We are
frequently asked what difference grooving makes.
First, it’s essential to understand that bearings depend on a film of oil to keep them
separated from the shaft surface. This oil film is developed by shaft rotation. As the shaft
rotates it pulls oil into the loaded area of the bearing and rides up on this film much like a
tire hydroplaning on wet pavement. Grooving in a bearing acts like tread in a tire to break
up the oil film. While you want your tires to grip the road, you don’t want your bearings
to grip the shaft.
The primary reason for having any grooving in a main bearing is to provide oil to the
connecting rods. Without rod bearings to feed, a simple oil hole would be sufficient to
lubricate a main bearing. Many early engines used full grooved bearings and some even
used multiple grooves. As engine and bearing technology developed, bearing grooving
was removed from modern lower main bearings. The result is in a thicker film of oil for
the shaft to ride on. This provides a greater safety margin and improved bearing life.
Upper main shells, which see lower loads than the lowers, have retained a groove to
supply the connecting rods with oil.
In an effort to develop the best possible main bearing designs for High Performance
engines, we’ve investigated the effects of main bearing grooving on bearing performance.
The graphs on the next page illustrate that a simple 180° groove in the upper main shell is
still the best overall design.
While a slightly shorter groove of 140° provides a marginal gain, most of the benefit is to
the upper shell, which doesn’t need improvement. On the other hand, extending the
groove into the lower half, even as little as 20° at each parting line (220° in total), takes
away from upper bearing performance without providing any benefit to the lower half.
It’s also interesting to note that as groove length increases so do Horsepower Loss and
Peak Oil Film Pressure which is transmitted directly to the bearing."

[87vette81big]

I prefer Half Grooved Main Bearings too.

When you build a Pontiac 455 or Olds Small Block or 425-455 You have a difficult time finding Half Grooved bearing sets.
Oldsmobile used fully grooved main bearings OEM except in #1 position.
Clevite only sells replacement full grooved main bearings for them.

The Clevite 455 , 421 main bearing sets are not a true half grooved set no longer.
#4 Thrust is now full grooved.
I have collected several NOS early Clevite & Vandervell Pontiac 3 inch & 3-1/4 inch main bearing sets last 5 years. True Half grooved.

They make it much easier for Chevrolet engines.

[Indycars]

What good is the world's best oiling system to the MAINS, if the rod bearings fail !

Would it not be a balance between the main and rod bearings, they both have to
survive ??? So the length of the groove would be right, when both main and
rod bearings have equal wear.