Pertronix Timing Issues

Grant- Is the motor equipped with dual carburetors? I'm asking because although 7.5' BTDC at idle is the spec, I have heard that dual carburetors like more initial advance (10-12' is stuck in my head, although I don't have a motor running at the moment to try it). I believe the way to tell if the motor has too much advance at idle is if it is hard starting when it is warm and just turned off (think stopping and running into a store quickly). If it starts easily when warm and never pings when accelerating off idle then I can't see any problem with it, but maybe someone sees something I'm missing. Is it possible to space the vacuum canister out so the points/breaker plate is not moving so much? Al 

Hello Alb:

Yes, I am running dual Kadron 40s on a 1600. 

The engine seems to be running well accelerating off of idle without any pinging that I am able to detect. 

I guess my frustration lies in the vacuum advance mechanism for this distributor and its inability to respond to the low ported vacuum signal from the Kadrons (of only about 5 inHg). 

I checked my vacuum advance canister with a vacuum guage and noticed that it needs at leas 8 inHg to start movement with full activation coming on at 10 inHg, which vacuum signals I am not able to produce with my Kadrons.

I thought having an SVDA distributor meant that I would have a total advance (mechanical and vacuum more like 40 degrees), and realize the benefits of such total advance in the form of reduced/eliminated flat spots and increased MPG.

Thanks, Grant

Grant-

You're discovering the Achilles heel of tuning these cars-- junk distributors. It's a bigger deal than the plugged idle jets everybody complains about, and I've got no less than 4 distributors I've tried to get it right.

The gold standard used to be the Mallory Uni-lite. It is adjustable for total timing, and timing curve. The vacuum advance model has an adjustable vacuum canister. They worked like magic (I hear) until about 2005-ish, when something changed. I bought mine in 2008-- one each of mechanical only, and vacuum advance. I hate them. I've got extras of everything-- extra caps/rotors, the advance kit, spare modules-- the works. The problem? Timing scatter-- they scatter like crazy.

I bought a Bosch SVDA from AJ Sims back in 2002, and in desperation stuck it on. It works well enough, but it is what it is. I've got 22 deg of total mechanical advance, and about 10 deg or so of vacuum. There's no readjusting the curve, or playing with the total advance. It works well enough to be "OK", but I'm going to crank-fire on the speedster this winter, and moving the SVDA over to my '64 panel.

As you know, the Bosch 034 SVDA is NLA, so we're left with used Bosch, Chinese copies, or Pertronix (which I'm not convinced is not the same as the Chinese knock-offs).

I think you're going to have to modify whatever you end up with to make it work. The current off-the-shelf options unfortunately stink. Crank-fire is infinitely cusomizable, but you've got to build it yourself or pay somebody else long money to make it happen.

The world could really use a good ACVW distributor... but as the hobby gets smaller and smaller, we're not likely to get anything better than what we've got right now. Sorry to be the bearer of bad news.

Stan: I just tried to dialogue you but I "don't have permission." No Idea what that's about.

Anyway. Just bought a Megajolt E and EDIS rig with trigger wheel and probably not going to use them in my Soob job. You have any interest?

I use the CB Performance Magnaspark Digital distributor :  http://www.cbperformance.com/P...asp?ProductCode=2016. It is not cheap but to me totally worthed. I like it as you can adjust the timing based on the vacuum and rpm to almost any degree you want. I have mine idle at 10 degree and it advances to 36 on a very light load (most likely when it decelarate from higher than 3000 rpm. To me it is a good compromise between being easier to install than crank fire, but still can adjust the timing with a computer.

Ed-

Is your Megajolt E MAP or TPS?

The trigger wheel will do me no good, as I have a tiny serpentine dry-sump pulley, and I'm going to need 2 EDIS set-ups (twin spark).

Email is: stangalat@yahoo.com

email sent

This might work on your setup:  http://www.thedubshop.net/shopping.html