Rotor/Reluctor Phasing Question

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Reddartowner said:
Actually, my guess would be not that your timing changed, but that the improved combustion from the HEI upgrade probably increased the strength of the combustion pressure wave, which increases peak cylinder pressure. Too high a peak cylinder pressure and you get detonation, i.e., ping. So you might need to dial in a couple degrees less advance.....
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Not using the vac advance ended up giving me the total that works perfectly.
 
Reddartowner said:
The vac can on the distributor is adjustable. We have already put 3 turns CCW into it, but with 20 inches of vacuum at idle, it still adds about 28 degrees. How many turns CCW can we go before the adjustment runs out ?
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...............r u sure ccw is the right way.........i have not did this in alota years and not very often..........kim.......
 
Not having a vacuum advance works well for WOT (wide open throttle).

A correctly tuned vacuum advance provides economy, improved throttle response and the same performance at WOT.
 
KitCarlson said:
There are likely a differences in VR interfaces, comparing GM to Mopar............................I like Hall gear tooth sensing better............With correct phase of the pickup, the trigger occurs in the level above the zero transition where the signal rapidly changes from - to +. Because the transition slope is great, the timing variation will be slight,.
Click to expand...

Having said all that, LOL, even "the worst" of a breakerless setup is far more stable and accurate than a Mopar single point distributor, and still quite a bit better than some of the best dual points setups.

My worst nightmare, "back in the day", a "du coil" Each set of points alternately fires one of two coils. This means that if either points is out of adjustment in relation to the other, half the cylinders are out of time in relation to the first half. You guys with older twin bikes know what I mean.

http://www.shastamustangsupply.com/ducoildist.htm

ducoilh13cap.jpg
 
Wow, that is an electro-mechanical solution for high rpm capability. A think outside the box, in the pre-direct-fire coil pack era. :) Thanks for sharing, while I imagined such a system, I did not know it existed.
 
Nice article with the exception of a post by Chryco Psycho, he deviates from the laws of Physics in this world. Ported vacuum at WOT greater than manifold vacuum, no way!

At best, tuning a mechanical advance distributor is a compromise. The RPM and vacuum curves are independent and do not include temperature, and smart interrelated compensations. Modern OEM ignitions (post 1996) are much improved with improved sensing means, 3D tables, and knock feedback.
 
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