[bdisanto]

I am rebuilding a 71 302, I had the blocked honed & bored to .040. All I did to the crank was clean & polish. I don't know the history on the crank but the engine was rebuilt in 1987. The existing main bearings are clevite 77 bearings stamped MB2121P above this stamp is has 010 stamped. ( I assume that means it was worked once before) The rod bearings are stamped CB634P and has an A stamped under it. All of the local autostores can not match these numbers and I have no way to "mic" the crank. Doe's anyone know what the current numbers are to the required clevite bearings??

Thanks

Ben

[wayne94mustang]

thr crank has but cut .010 and id say the rod area is stock size, my parts store has calipers and mics did you ask if theyll measure it for you?

[Tominator]

Nothing special here, but the crank has been ground to .010 undersize. That is fine, but you really should have the crank checked for size be a reputible machine shop.

Also, when you assemble the motor you should check the clearance via plastigauge[sp?] Easy to do and most repair manuals detail the procedure.

If the rods bearings do not have a .010 or a larger increment they are most certainly of standard size. Again, have them checked.

Find a parts store that still uses paper catalogs instead of computers. A competent counter man will be able to research those numbers rather quickly. The parts industry is inhabited mostly by button pushers.

In days past the mechanic came to the parts man for solutions of hard to fix components....not any more!

[bdisanto]

I had already checked the clearance of the main bearing with plastigage, the reading was .002 inches (or .051mm). That was using the old .10 bearings.

Your are so right regarding today's "Parts man" I used to get the best advise from the parts guy, now if it's not in the computer it doesn't exist...........



Thanks

Ben

[bdisanto]

OK, Here are the measurements;

Crank Journal - 2.238
Rod Journal - 2.114

According to the book the standard Crank Journal is 2.248 and the Rod journal is 2.123...
I do the math and find that the crank has been cut .010 +/- and I would need the bearings that are .010 larger...

Am I correct?????

[Tominator]

Yep, you are correct. Sounds like a good motor you have of the wear is only that much and it's 30 years old. :thumbup

[bdisanto]

Thanks for the help!

BTW the motor was rebuilt professionally by the previous owner at a shop in CA in 1987. is does have over 100K miles on the rebuild.

[GarageLogic]

Those are a regular 302 main bearing intended for a crank that has been turned .010 under. Replacement Clevite part # is MS590P10