Today I have to fit the cams, shims and buckets. This is not a simple job at the best of times.
It is made more difficult as the head has new valve seats which means there is no data for shim thickness.
How this is done is to make a guess at required shim size, install the cams, torque the head and join the cam chain before measuring clearances. Then it will 99 times out of 100 be wrong so the chain has to be opened, the cams and buckets removed in order to remove the wrong shims.
Then it is simply a case of calculating the required shim thickness now that you know the original shim size AND the resultant clearance between cam lobe and bucket.
So, basically with new valve seats it is a job that has to be done twice unless you are very lucky.
It is made more difficult as the head has new valve seats which means there is no data for shim thickness.
How this is done is to make a guess at required shim size, install the cams, torque the head and join the cam chain before measuring clearances. Then it will 99 times out of 100 be wrong so the chain has to be opened, the cams and buckets removed in order to remove the wrong shims.
Then it is simply a case of calculating the required shim thickness now that you know the original shim size AND the resultant clearance between cam lobe and bucket.
So, basically with new valve seats it is a job that has to be done twice unless you are very lucky.
Shims measured and data recorded Cams during installation
So, after some hard work the cams are installed and the valve clearances set.
The initial estimate for shim thickness was close, but not close enough, and all 6 shims had to be replaced.
Now the gaps are as they should be, 0.25mm exhaust and 0.20mm inlet.
The initial estimate for shim thickness was close, but not close enough, and all 6 shims had to be replaced.
Now the gaps are as they should be, 0.25mm exhaust and 0.20mm inlet.