o No: has anyone ever tried or have an opinion on the high performance(msd,pertronix,accel or proform) ignition modules available for the gm hei dist. ?i've heard a couple of different things like they don't help or make much of a difference.has anybody used one and if so, do they make much of a noticible increase?if at all?
I haven't used one myself yet, but I know several local 'roundy-round' guys that use the MSD unit. Supposed to deliver more voltage - can't say one way or the other.o No:
Mike Atwood's right, modules are for the most part, same in performance. Wasting money on them is just that. One module with the same performance as the GM 990 series is the NAPA TP45. 990 is GM's factory "performance" module. Now, the major problem with the large cap HEI is the cap mounted, covered coil. Heat generated within these epoxy filled coils causes increased/increasing resistance, which causes problems induced to itself and to the modules. Ever see an HEI that just plain blew module after module for no reason, then was finally magically fixed by a new coil? In-cap mounted epoxy filled coil was the problem all along. I see this every day, and with in-cap and some remote mounted EPOXY filled coils, both stock and aftermarket ultra whizz-bang ones as well. Best way to deal with rpm and heat problems in a large cap HEI, is to replace the epoxy coil with a remote mounted oil filled performance coil. This is easily done with an MSD 8401 coil replacement cap, has a coil wire terminal on it, and fits where the stock coil and cover sat on the distributor top. Add an oil filled coil like the Accel 8140, 8140C, a good quality magnetic suppression, spiral core coil wire and you will make the ignition system happy. Getting as much heat out of the cap area as possible is a good thing, and the in-cap coils are the main heat producers.
high performance ignition modules :Smarty: well once again i have been shown the light. thanks guys for the info, I didn't know the coil overheating could make that much of a difference but it does make sense. where were you guys a couple of years ago when i foolishly let some so- called performance shop talk me into an edelbrock 600 carb instead of rebuilding my q-jet . once again the board proves invaluable.
There are 2 good modules that I am aware of and they are NOT the same as GM. Accel and MSD make them. They are around 60 to 70 bucks. I removed an MSD 6AL box, and went with the Accell hi perf module. My idle quality is just as good as with the 6AL. That is impressive considering the car has a decent cam and all cross over heat is blocked off. My $.02
At least the large-cap HEI doesn't have the ionization problems the small cap does. I've never tried a remote coil on a large-cap, how would you go about doing it?
Ron, I believe it's as simple as changing caps, along with finding a mounting spot for the external coil. MSD has them, I think Jacobs Electronics has them, not sure who else.
MSD coil cap, p/n 8401, Accel 8140 or 8140C coil (don't waste your time or money on MSD Blaster or epoxy coils), coil wire and you will be set. NAPA TP45, Mallory, 990 GM, Accel, MSD, other modules that are all the same amperage, perform exactly the same. Oxidation is not a problem with small cap distributors if you coat the terminals inside the distributor with di-electric grease. I build real, live HEI and MSD trigger systems into points distributors every day, that's what I do for a living. Haven't ever seen ionization or oxidation problems when a conversion's done right.
Every small cap distributor I've ever seen has had stuff "growing" on the inside after a month or two. I don't own a car with one, so I'm not exactly an expert on them.
As I stated above, use di-electric grease on the terminals inside the capo, and the munge will not attach itself there, and spark efficiency will stay very good.
