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Old 12-11-2012, 04:24 PM
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Originally Posted by hcompton View Post
I use hastings rings, regular old moly rings will work best in the old engine total seals are very expensive but not worth the money without prepping the bore for low tension rings. The part number of the box on my coffee table is .030 over but you can match it up with proper bore size.
Hastings 2m 139 030

The last number is the bore size these are .030 over. 4.030 bore.

To jester: have your rods sized to the proper fit and you wont need to do crazy stuff to make your builds work. With the crank properly polished and the rods properly sized your bearings should be drop in if you buy quaility products. Use clevlite bearings and you can just drop them in place and check them with the plastiguage and they will be right over the life of the engine if they are replaced before the bearings fail and takeout the crank.

Acids do damage bearings by removing the coating of zinc and tin and other metals. Does not effect the copper or steel. Your proving my point here. Once you loose all the bearing material the engine needs new bearings. Plain and simple just like the ones in the pictures.

Bearing manufactures are hardly concerned that you need to turn the engine while building it. Modern engines are built by machine and all pistons are placed at once with the crank in second and everything linedup for install so the engineis not turned until it is started. Why would they patten a super coating that cost millions to develope if its totally useless.

Surely during the life of an engine it will see metal to metal contact. What if it sits for two years bearing can still get oil and be fine as long as the babbit material is still in place. Also hard corners or braking will cause lose in oil pressure. Crank will push the oil out in ms if the pressure is down. The only and entire reason plain bearings are made of soft metal.

Just for fun lets hear how making the rings grooves deeper can increase the ring gap aloowing a ring that is too long to be somehow shorter. If you have ever sized a set of rings you would know it does not envole the piston at all. I usally use my solid ring compressor to gap rings these days instead of using the bore to test fit.

To the OP sorry for off topic info. Had to let it slip.
Here we go! LOL

#1 the deeper ring groove comment is about a stupid person thinking it would work!!! not that you could actually do it!!!!!!!

Cast rings are forgiving!! They will form to an uneven or imperfect cylinder its the best ring to ignore imperfections!!! Molly coatings will wear off! Cast is considered forgiving has been for 100 years! The only thing to worry about is you cant role them onto a piston you need a spreader or they might break!! That's my opinion after 50 years of experience!

#2 I use Clevite And mic. them!!!! and find differences! There are no drop ins! You should have everything right before you even thinking about checking yourself with plastigage!! And you say they are drop in! Why would you use the plastgauge if they are drop in?????? What do you do on a blue print and ones a little too tight???? And bearing manufacturers are concerned about assembly procedures by builders and add the extra assembly coating its called "Quality"!!!

Being built by machines !!!!! Whats that got to do with this thread, Hes not a machine?????? This is about him building an engine at home!

Slapping together a rebuild in a couple of days isn't like a close tolerances engine!!!!! Even a stock Blue print!!! if the specs call for >.001 to .003 do you have your main journals all different 1 at.001", 2 at .025" and 3 at .003" etc. That's a half A S S build!!!!! They should be the same as close to minimum as possible on a good blue print or very close!!!!!!

The specs in the books are say .001 to .003 That's not the recommended clearance for persons new build!!! its clearances that are safe and when checking will suffice and an engine is ok!!!!! If you pull a pan and plstigage and get that clearance you can still run it!!! .001" is minimum needed, The .003 is max. over .003 it needs replacing!!!!!
If all the journals are at .003" with new inserts You have just built a wore out engine before its in the car!!!!!! 1,2,3,&4 mains need to be very close to minimum the same with all specs on the engine. Your machined block line bore and crank can be perfect but inserts aren't exact, you have to mike them !!!! and fit them to their best matching journal (like pistons to bores) if they don't come to the spec. order all 4 separately .001,.002,over to get a tighter clearance (or if too tight rework them)! The same with rods!!

I don't use plastigauge very often its inaccurate I do but only for a check with used dirty engines to get an idea! The reason many backyard engine builders like to use Plastigage is that they don't need expensive specialty tools like a mic or a dial-bore gauge. As long as the bearing surfaces on the rod and crank are clean, merely lay down the longer the strip the better the reading!

Read more: Plastigage Versus Micrometer - Accuracy Test - Car Craft Magazine

I never said anything about once the copper is showing they still good! I said "your bearings look good for that many miles!" 150,000 Miles after tear down!!!!!!

How does hard cornering and braking make less oil pressure??? Are you saying the pump pickup goes dry and sucks air? Or are you talking about race cars with no preventions for that or slosh! All the track tests by manufacturers led to designing cars that don't have that problem since the 50s!!! You haven't mentioned rolling a car on its top loses oil pressure and ruins bearings yet.

You said "Crank will push the oil out in ms if the pressure is down." "ms"?
If pressures down! Of course it does!! same with the cam! We aren't talking about engines wore out pumps with low oil pressure or wide clearance wore out engines! This isn't about coming up with scenarios on abused engines that's oil is never changed or run low or is left neglected setting for two years!! Its about normal wear over 100,000 miles!! On a well running car!! You haven't mentioned running it out of oil yet or driving it with a 2 inch hole in the pan, or never changing oil for the life of the engine!

I sent this early LOL I hit send instead of preview

Ill try to write the rest before I run out of time If you go to
Plastigage Versus Micrometer - Accuracy Test - Car Craft Magazine
And go on the picture I posted how far off plastgage is is pointed out!
All good mechanics know plastigage is inaccurate! And don't rely on its accuracy!!!!!!!!


This goes with the picture I hope it gets in the edit time!
Plastigage Versus Micrometer - Accuracy Test
After we torqued the rod cap and then removed it, we used the Plastigage package to compare its width to a particular clearance. While our careful mic measurements indicated a clearance of 0.0031 inch, the Plastigage indicated a much tighter 0.0015-inch clearance-or roughly half of what we mic'd. We double-checked our measurements, but the results were within 0.0001 inch.

Read more: Plastigage Vs Micrometer Plastiguage Photo 4
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Last edited by painted jester; 12-11-2012 at 04:53 PM.
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