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flatsix965 flatsix965 is offline
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Join Date: Apr 2011
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Originally Posted by TurboKraft View Post
Are you saying you set the piston to TDC and set the valve at full open, too?
If so, that's not a scenario that's going to happen when running.

Set the piston to TDC.
Adjust the valve lash.
Time the camshaft to the spec you want, lock it down.

Now carefully loosen the valve adjuster locknut. Since the adjuster has 1.0mm threads, 1.5 turns is 1.5mm distance. You should be able to rotate the adjuster bolt (elephant foot) 1.5x and still not have the valve contact the piston.

Even if you set the cams at full advance, you should have plenty of piston-to-valve clearance.

If it contacts, have valve reliefs machined into the pistons.
I guess I did not explain it clearly. The procedure in Wayne's book ask to measure the valve to piston clearance when the valve starts to open and continue every 10 deg until it is fully open. What I was trying to describe is that in my case the smallest clearance occurs at the end of this process when the valve is fully open which is after TDC and the piston is moving towards the crankshaft. Any idea what the smallest values (above 1.5mm) should be for my combination (930 cams regrinded to SC profile on stock engine)? Thanks!!
Old 04-22-2011, 06:06 PM
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