VCCA Home Forums TECHNICAL - 1945 AND NEWER 1946-1948 Plastigage

I am planning to use Plastigage to determine clearance
on crankshaft center and main bearing caps.
My parts guy has three different thickness. How do I
determine which thickness should be used?

Thanks in advance for your knowledge

Blue- .004 - .009
Red- .002 - .006
Green- .001 - .003
I'd guess that you would want to use green

Yes, get the green.
If you are doing the mains with the engine in the car support the weight of the cankshaft when checking.

"If you are doing the mains with the engine in the car support the weight of the cankshaft when checking."

Gene, this is a dumb-a** question: Couldn't you run up all caps without shims. It seems that this would hold the weight of the crankshaft as you removed the main caps, one at a time to plastigage them. When shimed then leave the cap in place.

I'm thinking that, because the crank is pretty stiff, the flex, if any, from one journal to the next would be minimal. I'd think that starting from the center one would be the best procedure.

Disclaimer: I have never done this. Accordingly, I have little faith that my notion has any merit. It's just something that popped into my head. You know.
Charlie

BTW: A possible flaw in my notion would be if you had to run the plastigage all around the journal (360 degrees) instead of just the cap. If so, how do you figure the pressure of the jack on the crank? I can't remember the procedure. It's been a long, long time since I've NOT used a engine rebuild, machine shop for this.

BTW2: Just for the record: I think you know what you're talking about and that I don't.

Thanks for the responses. Crankshaft support is not
an issue, the engine is not in the car.

While the engine is out you should also check crankshaft end play with a dial indicator.