I am switching over to an HEI based ignition in hopes of getting ECU ignition control to work. I have not been able to get either Accel or MEgasquirt to talk to, or in some cases read the distributor signal of this one.

So, I am going to the junk yard Monday to pick up mostly the harnesses. But I will pick up a coil and module just to have parts I can duplicate with new, so I know everything I have is compatible.

I have never worked on a GM new enough to have metric or HEI, so wonder what tools I should take. Are screwdrivers enough, or should I take along nut drivers and sockets as well?

Also can anybody recommend the manufacturer to use for the new module and coil? Is NAPA OK? I have seen a lot of griping about ignition parts on the forum. I want to get the best possible. I am not looking to cheap out on this. I want to maximize my chances of getting this to work.

Thanks for any advice.

Sam

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Sam get the large cap HEI distributer module with conecters with as much of the wire as possible (these should be the 4 pin module). Only need screwdriver and wire cutters not sure of screws that hold module in.

Richard

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Part of Tyrde-Browne Racing

Hi Sam.
In my car, I have a small, very cheap ¼ " drive metric socket set with both short and long sockets from 4 to 13 mm. also including extenders and a bit holder and some screw bits. For small bolts they cover most of the needs on a daily basis, whether metric or SAE, just see to that you include odd sockets like 7 and 9 mm that may be useful on US bolts.
Together with a kit screw driver with 4 driver shapes, it covers most needs for small parts repair or dismantling.
Pliers for stubborn wire connectors are always good to have.

Standard LX301 or similar AC-Delco module, all pics and numbers are in the electrical FAQ. Any good 0.5 ohm e-core coil can be used, I use the Ford coil pictured in the FAQ, Mallory and MSD and other high-performance coils can be used.
Use a good heat sink for the module, it gets hot. The number for the original GM heat sink is ACDELCO 10474610.

Some links:
HEI Electronic Ignition Retrofit How-To

Gm Hei Module Conversion Troubles

Keep us posted.

Olaf.

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Aspenized

Thanks guys. For this application I need the 7 or 8 pin module. And if I use the HEI coil, it has a tach drive, which I will need. Maybe there is another way to get a tach signal, but the conversion diagrams I have here use the GM tach drive to feed the dashboard, (real, not laptop) tach.

Actually I am thinking maybe the HEI ECU signal will also provide the dash tach count.

I will make sure I get the recommended tools collected before Monday.

Thanks Olaf for the links.

Sam

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Hi Sam.
A little red flag; check that the 7/8 pin modules also uses a 0.5 ohm coil, I have seen in catalogs that coils for engines with computerized engine management systems often use a different (lower) resistance coil. They is usually intended for modern OEM systems, but it never hurts to double-check!

The tach signal is usually just taken from the coil's negative post, independent of make and model (except old british cars and bikes with positive ground).

Olaf.

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Aspenized

Thanks for the heads up on that. I was just going to go OEM GM all the way.
Do you have any model or make of GM cars or trucks I should be looking at? I know very little about GM stuff.
Sam

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You can get a MSD 7 pin module ftom Summit that is sturdy and cheap.

There is an external coil/module/heatsink combo from late 90s trucks that makes a nice tidy unit.

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Yeah....Im the one who destroyed this rare, vintage automobile.....

I think the 7/8 pin module is computer controlled. I would and do use the older 4 pin module, they work good.

Richard

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Part of Tyrde-Browne Racing

I am controlling this with a computer. That is why the need for the 7-8 pin module. Thanks for the comment though.

Which would you distrust more, an MSD product, or an AC Delco part?

Thanks Sandy, I will look for a late 90's truck. I am not sure what they look like, but will look for the unified combo you describe. I guess they are big vans with somewhat rounded corners instead of hard square edges of the 80's.

Sam

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The MSD modules have an extended RPM range, I use them in all my EFI GM products.

The coil , heat sink , module combo is used on EFI Vortec trucks. I think there was a picture inone of the HEI threads.

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Yeah....Im the one who destroyed this rare, vintage automobile.....

Thanks Sandy. As it turned out, I needed a 5 0r 4 mm socket to get the dist cap off, and I did not have anything smaller than a 7 mm. The cap covered the coil bracket on all the Roadmasters they had there, and there were a bunch. So, I got only the harnesses, which is actually fine, as this makes wiring things up straightforward and simple.

Since I could not get the cap off, I could not see how the module plugs into the VR pickup. Is there a harness and connector under the cap? If so, I would like to track down the harness so I can make up a Mopar pick/up with the gm harness at the end.

Does anybody know where I can get this connector? I looked in the Echlin book, and there were thousands of connectors listed by part number. And tons of pictures, but no technical description.

Sam

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I built my HEI like dans and used a coil off of 90 astro van the bracket and heat sink I got off of a 96 S-10 blazer and used a 4 pin module off of a 80 C10 but with that module I had to trim one fin off the heat sink and use good quality heat sink paste. I know your not looking for that module and coil but you might check the 95-00 S-10s. I think they used a 7 pin.