RB26DETT Valve Clearance

How to properly shim RB26 camshafts. 

RB26DETT

RB26DETT/GT-R upgrades

WidgetBucks - Trend Watch - WidgetBucks.com

RB26DETT heads are dual overhead cam, 24 valve, direct acting camshaft.

The camshaft pushes directly on the cam bucket.  

The shim for setting valve clearance is located under the bucket, or shim under bucket.  This makes setting cam clearance a fairly long and involved process.


There are 70 stock shims between 2.275 mm and 3.325. The buckets vary in size a little bit, so you need to make sure you put the same bucket back in the same place when shimming the cams. Otherwise this will throw your measurements off. 

The exhaust side is tighter than the intake side because the stock exhaust cams are sodium filled. 

Intake side

Cold (20 C +/- 5)     0.45 mm +/- 0.03 mm    

(68F +/- 9)               0.018 in +/- 0.001 in

Exhaust side

Cold (20 C +/- 5)        0.38 mm +/- 0.03 mm  

(68F +/- 9)                  0.015 in +/- 0.001 in


Room temperature compensation

0 +/- 5 C    +0.02 mm

32 +/- 9 F   + 0.0008 in

10 +/- 5C   + 0.01mm

50 +/- 9 F   + 0.0004  in

20 +/- 5C     0

68 +/- 9 F    0

30 +/- 5C    -0.01 mm

86 +/- 9 F   - 0.0004 in