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TurboKraft TurboKraft is offline
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Join Date: Mar 2005
Location: Phoenix, AZ
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Originally Posted by flatsix965 View Post
The closest point is after TDC when the valve is fully open. Checked all the exhaust valves and are ok (above 2mm). The SC cams is the only modification on my engine and it has not been machined so I wonder why I am having this clearance issue. Both cams were timed close to 1.55mm with .1mm valve clearance.
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.
Chris Carroll
TurboKraft, Inc.
Tel. 480.969.0911
email: -
Old 04-21-2011, 11:51 AM
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