Piper Valve Clearances

[IBDAET]

Bit of a row going on at Webb Towers. Its centred around the definition of "Lift @ TDC with clearance".

I've always been a bit cautious when assembling engines hence have considered the figures below to be (inlet) .140" less 0.010" - (i.e 0.130") when setting lift at TDC, but now my assitant mechanic of the day is telling me I should set my cams to the full 0.140" on the vernier. See below:



So who is right? (I suspect Mr Andrews will be along to clarify....)

[DVandrews]

The lift at TDC shown is what you should set to, do not subtract the clearance. If you read the verbiage it is easy to work this out as the lift at TDC on inlet and exhaust is the same if the lobe centre is the same, this is true even if the clearance is different.

Dave

[IBDAET]

THanks Dave, I shall go munch some humble pie.