VCCA Home Forums TECHNICAL - GENERAL Mechanical - Engine, Trans, etc Shims

We had the crank in our '54 235 turned 20 on the rods and 50 on the mains, now I understand that the mains may be turned too much and may be weakened.
We would like to put the engine back together, but it is going to have to be shimmed.
My question is: What is the best way to start to shim it?
Do we start out with .001 and see if the crank turns and if not go up a .001 until the crank turns.
I bought some brass shim material at the local hardware store (.001) is this material going to be ok to use or should I try NAPA?
Any help from you guys sure would be appreciated.
Thanks, Bob

You may want to see if you can find a good NOS crankshaft or a good used one, if you don't trust the ground mains, rather than trying to shim ( don't the machine shop have access to undersized Main bearings?)
The cranks from 1953 (Powerglide tranny) up thru 1962 235 c.I. engines both cars and trucks will all use the same crank #3701486, some that have been in a powerglide equipped car may not have a pilot bearing, but that can be drilled by any machine shop.

The .050 under mains should be no problem as far as the crank shaft goes.Its a forged shaft and very hard.The big problem would be as to how the bearings were brought to .050. If they used a thicker insert and the same "thin" babbit as a standard size it should be no problem.You will have better mains than 95% of the original cars out there.If the machine work was done as a new block and crank would be you would start with four shims on each side-2 .001 and 2 .002...Then remove shims until you feel a drag when turning shaft and add one shim.Not knowing what was done and how you could start with no shims and add one at a time till drag is gone-either way it will end up the same.After doing the first one you will get the pattern and the rest should come out about the same as to how many shims will be required __if any :confused:

I would put in more shims than required leaving a loose fit and then remove until drag occurs. If you tighten down too tight it will distort the bearing material and give false feel when you add shims.
Rember the bearing material is very soft and will distort easily.
There is a thread eleswhere on this forum where I think a bearing cap tightened down incorrectly has caused major problem and no doubt many naughty words.