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Today I measured my valve shim sizes using the feeler gauge method. I'm using Tomei Procomp cams, Tomei solid pivots, and Tomei test shims and guides. I used the Tomei formula to calculate the sizes.

The formula is:

Measured Size - Desired Clearance = The difference you record

Nissan Recommended Clearance is 0.14 to 0.17mm. I used 0.13 because of new cams, etc.

Difference X Constant (1.43) = Adjustment Value

Adjustment Value + Test Shim Size ( IN 2.8mm, EX 2.7mm) = Shim/Guide size
needed

But some of the values I got seem a bit high to me. Here is what I got for values:

Intake:

Guide Shim

1) 2.96mm 1) 2.96mm
2) 3.05mm 2) 3.01mm
3) 3.11mm 3) 3.11mm
4) 3.12mm 4) 3.13mm

Exhaust:

Guide Shim

1)2.99mm 1) 3.02mm
2)3.06mm 2) 3.02mm
3)3.02mm 3) 2.99mm
4)2.99mm 4) 2.95mm


The thing that alarms me is that some those sizes dont show up on the Tomei website. I know the oversize shims or guides can be ground down, but what about the bigger sizes? Do these numbers make sense?

Is there any way to check out the clearances before I order the shims and guides.

Any help would be appreciated.
 
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