Quote:
Originally Posted by gwhite
Have you experienced pinging at 5.5+ CR? The manual advance of the A allows for up to 40*...do guys running HC heads typically back off the spark lever?
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Yes on the pinging.
If you pay close attention, you can feel the engine over work even before it pings when the spark is too far advanced. Try it while not moving. Advance the spark at mid rpm range and you can feel the engine no longer increase in power when you go just beyond optimum, then as you advance further it will start to labor. Too much advance is aggravated when under a heavy load, like a steep hill climb or high temperature.
I never go beyond 28 degrees anymore with a 5.5 or higher head. Most of the time I advance just beyond half mast with a Brumfield 5.9 head that has been surfaced a few times, so the compression is higher now.