So....Which is better?

[fb71]

i bought a pertronix 2 system and used it for about a month before throwing it away it worked alright for the first few weeks and smoothed out the idle i didnt have the flame coil i used my stock 12v which was fine but after a while of driving the car it would stop firing on 2 cylinders no matterhow i adjusted it replaced coils or took ohm readings it always went back to the ignitor i now just rely on simple points and they have great for a while now.

I have found the PX II is sensitive to the quality of its ground connection. It senses current flow and compares that to frequency to adjust dwell time. A noisy (crappy) ground drives the processor inside nuts, and it 'hunts' for an appropraite dwell, which can cause randome misfire. (I've verified all this with both an old Hitachi 20MHz analog scope and a Snap-On MODIS scope function). Extended operation with a poor ground can also lead to premature failure of the output transistor. (happened to me). PX stepped up to the plate, and replaced my unit for free (lasted about 15hrs with the poor ground), and I have not had a bit of trouble with the second unit (about 100hrs). What clued me in was PX's failure analysis report that arrived with the replacement unit. It suggested I inspect the distributor grounds. Diagnostics revealed just over 1v drop across the ground strap in the dizzy (from the breaker plate to the baseplate). That's what lead me to scope it, and the erratic pattern I found verified the fault. replacing the strap (just made a new one with a piece of bare 14ga stranded and two crimp-on eyelets, soldered after crimping) flattened out the voltage signal across the ground circuit, and reduced ground-side voltage drop to 0.009v.

 

[fordconvert]

Another possible option is something like a MSD 6 box. They aint cheap either but you can trigger them off of points and the do have a hotter (maybe much hotter) spark than other electronic ignitions (like duraspark). The points are just used to trigger the electronics in the box so in theory the points will last almost forever and the dwell/gap is not critical because the box now controls the dwell and handles the full load of the coil. I have one on my 4cyl boat and it does seem to help a bit on power and idle. You can hear the buzz from the multi spark thing. Im not sure that it would be worth $300+ retail on the box if I had to buy one new but for what I paid it works well and its now electronic so I dont have to keep messing with points. They come up on ebay, craigslist, junkyars, and garage sales fairly often.

Im not saying its the way to go its just another option that you may like or may have been thinking about anyway. Becides triggering off of points they work on stock electronic dizzys like the duraspark and Hei (DUI) so if you decide to ditch the points later for some reason you can still use the expensive box.

 

[AzCoupe]

Here's my thoughts on all this.

GOOD For a stock motor used as a daily driver or those restoring and wanting to keep the original OEM looks, the Petronics is going to work fine. Its also the best deal, price wise.

BETTER For those who want more power, better idle, quicker starts, and don't mind spending a few extra bucks, the DSII is tough to beat. Plus you have several options for spark control, with varied prices.

BEST For those who see the track occasionally, or want as much power as possible, the DUI is the way to go. It expensive, but it will out perform the other two hands down (proven on a dyno).

All three are better than stock points, yet all three have service issues, even the DUI. However, the DUI is going to be the easiest system to find parts for. If your worried about reliablity, keep extra parts in the glove box or trunk. Especially the parts that can't be purchased at your local Autozone. This means ordering an extra Petronics (Petronics), a spark controller (DSII), or a dyna modual, coil, and cap (DUI).