The Petronix unit seemed to make a real difference over the original points, both on a stock and then a warmed-over 1725. Lots of maintenance-free miles, with no erratic pinging. Now I'm thinking of taking another step up.
To those who've gone to MSD: Are you happy with MSD? Any noticeable power increase? Any headaches?
Dick Sanders
Kent, WA
I am not a big fan of either, but they are in a whole different league.
The pertronics is just a basic lower end electronic ignition system.
I'd say its not much different than the others, but due to its design, it is NOT the same from a timing accuracy standpoint.
Heres why:
Pertronics uses a ring in the cap that spins on the dizzy shaft. This is not so different than the other. Where they go wrong is that the ring has 4 magnets (for a 4 cyl) cast into the ring, which since each magnet may or may not be positioned accurately, and each magnet may vary in its magnetic strength.
The result is that the timing from cylinder to cylinder varies. You might set the timing with your strobe light using #1, but #4 (360 crank degrees later) might show 5 degrees retarded timing. the same goes for #2 and #3, which fire at 180 degrees off the #1 and #4 timing marks.
MSD seems to be making some real crap these days. There is a cottage industry that has developed repairing them since the warranties are about as good as the product. The higher end systems DIS4 and DIS8 products are higher reliability than the old CD ignitions that made MSD famous, but these are much more expensive, and involve a crank wheel to be added, which is outside the cost and complexity level for most DIY folks.
When I first started designing engine management systems, I used to recommend the pertronics for basic ignition, and the MSD 6A, 6AL 7A or 7AL for more demanding race applications. Through time I got burned enough times from each system that in order to stay in business, I had to design my own ignition system that I integrated with the fuel injection system.
Today, short of touting my own systems, I would recommend either a Crane XR700/XR3000 or a luminition optronic igniter.
Both use an optical wheel, which is much more accurate that flying magnet triggers used in the pertronics, and some MSD systems.
