Quote:
Originally Posted by Dan Fahey
Curious. Why more Clearance on the Intake vs Exhaust. ?
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Should be more clearance on the exhaust than on the intake. Observe the relationship of the valve action in comparison to the rotation of the engine during the cycle. The piston is closest to the intake valve as the piston is approaching TDC and the valve is closing, so any contact will "push" the valve closed and/or the clearance will increase rapidly. For the exhaust valve action, the opposite is true. The piston is closest to the exhaust valve as the piston is approaching TDC and the valve is opening. The camshaft will push the valve into the piston and potential damage is greater.
There are other factors like what causes valve float, etc., but the above is generally true.