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Valve Adjustment Guides
Published 10 Sep 2017

Pratt & Whitney Wasp Major
Valve Adjustment Guide
Radial engine cam rings typically have very large clearances between the rings and spigots upon which they rotate. This makes valve clearance adjustment tricky because the cam ring must be positioned in a predictable location during valve adjustment. Further complicating the valve adjustment process is the desire to complete the task with minimal engine rotation. Radial engine designers developed procedures that allowed accurate valve clearance adjustment to be accomplished while rotating the engine as little as possible. The data used for these procedures was usually presented as tables in maintenance publications, but were also published as quick-reference guides. Valve adjustment guides for Pratt & Whitney Twin Wasp, Double Wasp and Wasp Major engines are presented here, courtesy of Ted Koch.



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