hows it going everyone!!!first off,first time posting here and id like to say thanx for any help that can be offered, as im semi noob with working on cars...i have a 68 225 im rebuilding and wanted to replace the main bearings,mind you ive never done main bearings before...i ordered a set of 4092M standard set assumeing thats what i needed for the build...they offer .01,.02,.03,.04 sizes...when they arrived they were waaaaaaay to big...how would i find out the right size for this block???

block number 2806830-4 other punches 0202 AAWJ BH

its a 225 1bbl 3.7 if i matched the block correctly?

 

DO you have the old bearings ? There will be a part# on the back.. As for them being too big ? The crank may have been rebuilt sometime previously in it's life So you may need a .010 or .020 undersized bearing What type of rebuild are you doing ? Is the crank out of the motor?
Would be advisable to have it checked

 

crank is in the motor still...the motor is in a lull...it has a hydraulic pump attached to the front of the engine bolted to the crank pully so i didnt want to pull it out as its a pain in the @#$...i was just tgoing through it doing rings new haead gasket and so on and figured whille the pan was down getting a scrubbing id do the crank bearings and make sure everything was torqued down tight since its an old engine...the stadard crank bearings i got were like a 1/2 inch to big...that seems more then .01,.02,.03,or .04 bigger then a standard crank grind...thats why i decided id check here for some advice on how to determine the crank bearings size...

 

why did i not hear a word about using a micrometer?

 

Some type of industrial engine ???? Were their #s on the old bearings ?

 

I want to help but don't understand if the crank and bearings are still in the block how do you know they're too big?