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dr bob dr bob is offline
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Join Date: Jun 2009
Location: Central Oregon
Posts: 71
Just a reminder that the distributor turns at half the speed of the crankshaft. Moving the distributor body --4-- degrees will change from 23º BTDC to 31º BTDC at the crank.

It's easy to get a little carried away with advance at idle, since the engine seems to run smoother/faster at idle with the extra advance. If you go overboard though, you risk detonation at higher engine speeds, detonation that you may not hear over other noises until too late, when it turns into a rod knock or a serious piston slap. Depending on fuel quality, a couple (crankshaft) degrees is genally not too unsafe, but no more on good pump premium gas. Also, if you have -any- lean cylinders because of less-than-perfect injectors, you risk lean detonation with any extra advance.
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dr bob

'89 S4 Auto, Black
(Needs to be cleaned)
SoCal928 Co-Founder
Old 03-21-2010, 02:23 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #18 (permalink)