AlphaOmega74

Did a cam swap and was checking lifter preload. This is what I came up with:


Cyln: int. .exh
1: .059 .053
2: .048 .053
3. .039 .059
4. .039 .053
5. .048 .059
6. .059 .059
7. .048 .059
8. .074 .053


I've done lots of researching on this site and others. Seems like the accepted range of preload is .030 - .060. I'm barely within specs except for #8 intake. I measured twice. With the research that I have found, shims should fix that, correct? Do I have to run an even amount of shim on the #8 exhaust as well for evenness?

cutlassefi

Got your pm.
Yes the .074 is a bit much. I'd shoot for .045-.050.

MDchanic

If you shim the rocker pedestals, remember to divide the change you want to achieve by 1.6.

A 0.005" shim will get you 0.008" of compression.
A 0.010" shim will get you 0.016" of compression.
A 0.015" shim will get you 0.024" of compression.
And, yes, you can stack the shims, within reason.

So, to get your 0.074" preload down to 0.034", that's a reduction of 0.040" of preload, so 0.040" ÷ 1.6 = 0.025", or one 0.010" shim and one 0.015" shim.

You can shim each pedestal on a cylinder a different amount, and will probably have to.

Here are links to shims on Amazon:



And, remember, shimming like this is not stable enough for high-rev, high-lift, heavy-spring applications.

- Eric

AlphaOmega74

Thanks for the responses. Eric, glad you gave me that math lesson. I would have just subtracted the amount of shim from the existing preload. I ordered the Crane kit over the weekend and will let yall know how it turns out.

MDchanic

You're welcome. It'd take a while to figure out otherwise, and probably involve some wrench throwing.

- Eric

oldcutlass

Not to mention the proper vernacular to go with it.

AlphaOmega74

Update. Finally got the other shims in from Amazon. I had the Crane kit but the smallest shim reduced the preload by .029 which would have been too much for most of them. Got them all between .039 and .045. Thanks again fellas.

MDchanic

You're welcome. So how does it run?

- Eric

AlphaOmega74

Waiting to get the Qjet back from SMI.