A10 Valve clearances

[bsa-bill]

Not sure about that Josh, does longer open not also mean more overlap? gotta keep the suck away from the blow.

All the best - Bill

[beezalex]

Please correct me if I am wrong, but, less clearance would equal longer open times and greater volume exchange, i.e more power, cooling and less noise ?.

I don't see why it would mean more cooling, but one thing I do know is that more power=more heat, hence the problems with the clearance closing up when you're really flogging, 'em.

[BSA_54A10]

Tighter clearences do reduce noise and aid hight speed running at the expense of low rev power.
Logic goes like this,
At low revs not enough time to properly fill the cylinders at the lower gas velocities and add to that losses from the fresh charge wafting out the exhaust valve do to longer and larger amount of over lap.
Also reduce the clearence between the valves & the piston.
The opposite applies to sloppier settings used fro high speed running