Thread: cam timing
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Old 07-23-2011, 07:08 AM
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Join Date: Dec 2008
Location: Sugar Hill, GA
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Default Re: cam timing

Originally Posted by john910
now if i advance it, will i have any issues with valve to piston clearance. or will that stay the same. thanks for your help.
For stock motors, .045 is the minimum valve to piston clearance
On High RPM motors, use .080 on the intake and .100 in the exhaust.

1. Write down the lash you will use (example Int = .028, Exh = .030.
2. With the cam on the heel, adjust the lash to zero, do not lock the polynut.
3. Put a dial indicator on the rocker, just above the spring retainer.
4. Intake number = .080 minus lash (example .080-.028 = .052).
5. Tighten the poly nut .052.
6. By hand, rotate the crankshaft while watching the rocker go up and over the nose of the lobe "feeling" for interference.
7. If none, tighten another .020 and rotate again. Repeat and you will eventually find your clearance.
8. Repeat for the exhause (example .100 - .030 = .070).

If you change the advance on the cam, you must start over.
JMP but works from me.
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