BB valve spring shims

[Joe R.]

I'm working on my shopping list for the valve train on my L-72 (427 / 425) that I am rebuilding. Can I reuse the valve spring shims or should I buy a new set? If I need new ones, what is the GM part number?

Joe

[Joe L.]

Re: BB valve spring shims

I'm working on my shopping list for the valve train on my L-72 (427 / 425) that I am rebuilding. Can I reuse the valve spring shims or should I buy a new set? If I need new ones, what is the GM part number?

Joe

Joe-----


You may be able to reuse the shims but I think that if I was replacing the springs, I'd replace the shims, too. They are GM #3875916 and they're still available for about a buck and a half each, GM list. These shims are 0.70" ID, 1.48" OD and .016" thick.

[Clem Z.]

Re: BB valve spring shims

no matter what shims you use make sure the are hardened by hitting them with a file

[Joe R.]

Re: BB valve spring shims

Clem,

Can you please elaborate on what you mean by hitting them with a file? What type of file and what result am I looking for?

Joe

[Clem Z.]

Re: BB valve spring shims

Clem,

Can you please elaborate on what you mean by hitting them with a file? What type of file and what result am I looking for?

Joe

take a machinist file and push it across the edge of the shim and if the file cuts into the shim it is NOT hardened and will wear from the spring moving on the shim putting metal particles into the engine. if you need more than one shim to get to the 1.880 distance use a hardened shim directly under the spring but you can use non hardened ones under the hardened shim to get the correct distance.