what if....... what if my crank needed .30 over bearings and i have .25 over bearings... would that make a @!#$ ton of noise i'd hear all over, but over 15k miles the noise wouldnt get worse, and the bearings wouldnt spin by then?

i ask because the machine shop failed to mic the crank and just installed .25 over bearings because we thought the gm reground crank was grounded .25 ... i noticed on an 80 degree day that at 700 rpm the oil light came on when the motor was a little past half on the temp gauge... this morning, about 45 degrees outside, the temp guage was about half, and the light wouldnt come on until it dropped below 500...

i'm asking if this is a possible theory before i tear the oil pan off and use plastigauge to measure....

if you dont know for 100% fact then yes you should probably check it out man...

for them to grind it to like .30mm is as far as i can tell retarded because we can only get .25/.50/.75mm bearings from the aftermarket. now.. i dont know what GM offers but thats all ive seen over the years.

what we need to be careful about is when the machine shop grinds to inches and not millimeters. sure its close but its not EXACT.

Edited 1 time(s). Last edited Wednesday, April 06, 2011 5:19 AM

so im basically screwed either way unless the crank is .25 since i couldn't get bearings between .25 and .50 ... if its .05 too loose, should i yank the crank and grind down to .50?

up to you man... if you feel the work is worth it than id say go for at least checking it out with plastigauge.

I would test the oil pressure first, just to rule out the sensor before you go tearing the pan off.


- Your not-so-local, untrained, uncertified, backyard mechanic. But my @!#$ runs

What oil are you running? Larger clearances require thicker oil (eg, bearing clearanges on the new ford engines are .0008" thus requiring 5w20 oil, while traditional old smallblocks ran .0025" requiring 10w30). This explains low oil pressure at idle with a warm engine.

For one to just throw a bottom end together without measuring anything, is very bad workmanship and bad practice. Personally on that note I would probably drop the pan just to have a look anyways, but for @!#$s and giggles, check the oil pressure with a master gauge first, and you can try a thicker oil first if you feel all is ok in the bottom end.


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** Flat Broke Racing Inc.**