When going from stock points to one of the Pertronix conversions will the location of the Pertronix module change static timing much, if at all? Of course one would want to check timing after changing from one to the other but, I'm wondering if a module fails on the road and the points are reinstalled to get home, would the timing be close enough to just drive it without retiming? My question applies to any of the points conversion modules out there. (Pertronix, Crane, Lectric Limited, et al)
I've had a Mallory conversion and the Pertronix Ignitor III in the stock distributor. The initial timing is all mechanical, same with the spring weights and vacuum advance. I think you would be ok without having to re-time. With that said, I haven't had one fail with over 15,000 miles driven.
The pertronix runs on 12 volts, as opposed to the points on a resistance wire. Converting back to points on the road because of failure is not so simple. If you carry an extra points distributor and a coil you can just disconnect your resistance wire at the bulkhead and have a straight 12 volt wire for the Pertronix. Then reconnect the resistance wire for the points. The points won't last too long on 12 volts. Depending which Pertronix you have to run their coil with specific resistance. I cannot quite remember but I think you can run a points coil for the first generation but they recommend using their coil "for best performance"
Run Pertronix 3 and the matching coil, nothing else changes. Mine been flawless for 7-8 years now in all my cars, plus built in rev-limiter.
The next time I do a conversion I'll have to pay attention to how much, if any, adjustment is required. You can run your points system on 12 volts but the life of the points will be shorter, probably half. If you put your points back in and you hear pinging just keep your foot out of it.
Dwell changes timing, timing does not change dwell. If you had to install points on the road, you would need to adjust dwell for the timing to be right.
Larry is mostly right, but you wouldn't adjust the dwell to set the timing, which I'm sure he knows. The dwell setting is for phasing the rotor to the coil firing. Once that is in spec then the timing can be set. But to answer the OPs question, the pertronix should be phased the same way, so in theory if the point was adjusted properly then the car should run fine..
Actually, in my case, I would only have to remove the resistor wire that activates the relay that supplies 12 volts to my coil and reconnect it back to the coil. It's actually located right next to the coil now. But Larry makes a good point about resetting dwell so, I'll have to keep my old dwell meter and adjusting tool in the car along with a points/condenser combo. (Or, just leave the 12 volts connected to the Blaster coil if the ride home is a short one and I'm not concerned about point life)
Correct, my reference would be to the installation of a new set of points. I remember back in the day, they were at least set up out of the box close enough so the engine would start, and then you could check and adjust the dwell, and all was well. These days, that isn't so, at least not the few sets I have installed for others. I always find them way out, and need to make a static adjustment just to get them close enough to start. Ray, what you could do is set up a new set of points so the dwell was spot on in your running engine, then remove them, reconnect the Pertronix, and you would have a fully adjusted set of points to use as your spare.
Nope. "Dwell" is adjusted to provide acceptable coil saturation vs. coil and points overheating. It's a balance of performance vs. longevity. Too little dwell, the coil isn't charged enough especially as the RPM increases. Too much dwell, excess current flow heats the primary circuit including the coil windings and the points. Too much dwell also promotes point set arcing as they don't open wide enough to stop current flow--the primary current could "jump the gap" and then the points burn and the engine stalls. IF ONLY there were a way to have a short dwell at low RPM, and a longer dwell at high RPM! An excellent reason to dump the points in the scrap bin, and go HEI. Dwell varies with RPM, increasing as RPM increases within the limits of the circuitry, and electronic current limiting prevents system overheating. A PROPERLY-FUNCTIONING HEI gives up nothing to points, is better in pretty-much every way except for the larger cap being inconvenient in some applications. Phasing the rotor tip to the distributor cap terminals is done mechanically by several systems, geometry engineered into the distributor by 1. Vacuum advance pull rod length on the breaker plate, and distributor cam-to-mainshaft positioning being the main two. The common cheat for distributor rotor phasing is a hyperexpensive adjustable rotor.
Longer effective dwell ALL the time, but with current split between two points sets most of the time so they don't overheat, and they open a reasonable amount. But the coil is still flowing additional current regardless of rpm.
All that is neat, but as the dwell changes the rotor phasing changes with it as the timing of the firing of coil changes.. thats inarguable.
Nope. Proper rotor phasing is a fundamental part of any distributor ignition system. It's certainly not a "side effect" of a properly tuned system, and its certainly no accident that the phasing is proper when the dwell is set to spec. So yes, it is a large part as to why the dwell is set...
