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Old 11-23-2017, 02:14 PM   #39
Simonpie
Senior Member
 
Join Date: Mar 2015
Location: Portland Or
Posts: 135
Default Re: Noise in my new 29 a engin

Quote:
Originally Posted by Railcarmover View Post
I've got a few questions...

how does a higher compression head alter the operation of a gyro style advance on the distributor shaft?


How can you effectively measure the optimum 10 degrees of timing for each 1000 rpm with a quadrant lever?
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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