Pertronix Ignitor: Dwell

[DoctorMuffn]

For those of you running the ignitor what are you getting for a dwell measurement?

[d240zx2]

Ya know, I've never measured it. The car runs so well with just the drop-in system, I never even thought to check dwell. AAMOF, I don't know if I'd know how to do it. ;-)

[Arne]

I'll probably have time to hook up the dwell meter after work on Wednesday.

[Zforce]

Ok, what if the dwell is out of spec, how can you adjust it ? Is dwell determined by the distance between the trigger magnets or by the transistor in the ignitor module ?

I am also trying to pin down the mystery brick wall at about 4k revs, I am not sure if its ignition or fuel but it is driving me nuts. Pertronix claims the ignitor II has adaptive dwell which is supposed to optimize dwell at all rpms buy I have a feeling its all BS.

I have the pertronix installed in a mallory duel point dizzy my next project will be to upgrade it to a unilite if I cant get the pertronix to work right.

I will check the dwell and report back what I get tomorrow.

[DoctorMuffn]

See akorna's post made on the 22nd in the following thread. I'm gonna see if I can manipulate dwell on my ignitor following his measurements.

http://www.classiczcars.com/forums/showthread.php?t=37452

[Arne]

Assuming that my 35 year-old (and very cheap at the time) dwell meter is reasonably accurate, I'm showing ~35° at idle. Bottom of the spec window. Increases slightly as the revs go up, but not more than 5°, still within the spec window. This change might tend to confirm Pertronix's claim that the Ignitor has "adaptive dwell" which is somewhat variable.

Or it could indicate that my meter is crap.

Edited March 25, 2010 by Arne

[alhbln]

Ok, what if the dwell is out of spec, how can you adjust it ? Is dwell determined by the distance between the trigger magnets or by the transistor in the ignitor module ?

Correct, the distance between the magnets sets the dwell period, you can't change dwell without modifying the sleeve/magnets. The transistor in the Ignitor I setup just does the current switching, no dwell or current control is supported.

[Zforce]

Ok I checked mine and it's sitting at 37 degrees and drops to 35 when I rev it.

[alhbln]

Hmm, i got 38º from 800 RPM up to 4000 RPM on the distributor tester. The dwell angle should not change for different RPMs, just the dwell time, at least for points based and simple transistor ignition systems.

I wonder if the dwell angle variation you guys have seen with different RPMs would indicate a worn distributor or if the Pertronix Ignitor is somewhat voltage/current sensitive.

[Zforce]

I'm using a mallory dizzy that's in good condition so I think it is sensitive to voltage fluctuations especially with the external voltage regulator alternator. Soon I am going to upgrade the alternator and test it again and see what happens.

[Arne]

I re-checked mine, and I find I had read the meter wrong. Mine is at ~35° at idle and also drops slightly with increasing revs, not increasing as I wrote earlier. As to why, I'm also leaning towards current sensitivity, due to my other symptoms with EI, and the fact that the ZX alternator addition did seem to help some of my issues.