Quote:
Originally Posted by Simonpie
Railcarmover, The head doesn't change the timing. The head changes the engine's need for certain timing. Generally, higher compression causes higher peak temp on compression just before ignition. This causes a faster burn, so the engine needs less ignition advance. A similar effect can happen with a cam, manifold, or exhaust change. Different cylinder filling at different rpm's makes the burn rate different, so different ignition timing may be needed.
The only way I know to measure a bob weight type advance at different rpm's is with a tachometer and a timing light.
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My point in question brother...how can you effectively monitor the changes needed in timing with a lever? and why? especially given a center main expected to handle the impulse from four cylinders with no more area than a front bearing that handles two cylinders? regardless of timing required by a raise in compression, the basic need for a mechanical ramped increase in timing is critical for engine life as a whole. Harold Hicks,the ford engineer brought in from aircraft design to raise the hp to 40 noticed a main bearing weakness with the design...but was shot down by Mr Ford,who allowed his redesign of the exhaust manifold and additional cooling around the exhaust valves,but felt the three main bearing design was adequate..but he nodded with the B engine,offering mechanical advance from the jump...and a counterbalanced crank...