Is it possible to use a 7 pin HEI module in place of a 4 pin? I may eventually convert to a GM TBI computer or MS but would still like to run HEI with the carb and mech/vac advance distributor before diving in to the whole deal.

Would rather save the money later on buying a different module if possible.
Brandon

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https://www.flickr.com/photos/162600228@N03/

So, I just got done digging some info through the search bar and came to a conclusion that the 1st part of this sticky is kind of "misleading" in a sense. not denying the true talent and skill writing it up but if it could be modified a tad bit by showing 3 different sources to how the coils are wired up. that being said I have ordered 3 different coils online, Long story short I had a problem finding connectors for them to make the install look cleaner. But what I have noticed in the write up that the different pics of the coils are a bit confusing, I repeat the coil pictures are confusing. nothing related to the hei module, its kind of self explanitory and so is a standard relay. the differences of the coil sources used gets confusing due to all of them have different connectors and frankly of all the ones I have purchased (cheaply) are not labeled so I find myself looking and rereading the sticky and scanning other posts to see if I can decypher how they are wired and see the connectors and figure out where they are going. Once again I dont want to take anything away from his Superb write up. but for us cavemen and women that dont have a degree in electrical could we make a small sticky explaining the different coils and there connections???

See my write-up about the HEI upgrade of my car. HEI Igntion Upgrade.

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1965 Plymouth Barracuda,
225 engine, Quadrajet, HEI, Dutra Duals, 904 Torqueflite, 2.76:1 axle, Addco front bar
Rods & Relics - Fort Erie, ON / Collector Car Tech

I try to gather all the stuff required to do a HEI conversion. First thing I noticed that prices were much more favorable at the time SlantSixDan wrote the article ... my Amazon basket is already filled with goodies worth $100 and haven't even purchased an electronic distributor and some serious ignition wiring. Let alone the shipping costs. I wish the EUR.USD dollar was 1.4 again.

Anyway, in the article it says to use a relay. Prong #30 is used for the power input and it is adviced to use a fuse holder in this wire. My question is (not being hindered by any electrical knowledge):

- Can a fuse relay switch be used for this purpose? It looks like an elegant solution from what i can tell.

You could try RockAuto.com. I am sure they will have some inexpensive alternatives. Just watch the shipping.

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-MattMan
LEANED & MEAN

After finally converting my old dodge to HEI now I have another problem. The alt meter wires under the cluster are getting hot. Also my line voltage to the battery is now only 12.99 volts. I’m pretty sure it’s supposed to be around 14. Would anyone know if there’s a way to check the alternator to see if it’s putting out the correct voltage without taking it to a shop? And has anyone else run into this problem after the swap?

The heat at the ammeter connections is from high resistance. Fix it or you can melt the panel where the studs come through or even the insulation on the wiring. It's obvious that the alternator is putting out power. If it were not the voltage would quickly fall below 12.6 and there would be not heat as there would be no current flow. Disconnect the battery, fix the ammeter connections and any others that are showing signs of distress or voltage drop. Charge the battery with a battery charger. Reconnect the battery, start the vehicle and then check the charging voltage.

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Joshua

Thanks. Will try that tomorrow if I have time

Well I found a problem. Somehow somewhere my positive and negative are connected. Both battery cables read 0 ohms meaning there is a short somewhere. Now to hopefully find out where it is and fix it. Stay tuned and I will post my findings in case anyone else runs into this.

Odd. True shorts at the battery connections tend to start fires. Disconnect the battery, the big wire at the alternator, turn off all loads and try again. Also, this needs to be moved out of the HEI discussion thread.

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Joshua

Will leave this be here. Will continue in electrical sub-forum. Thanks

I'd like some troubleshooting help with my HEI conversion please.

I though I should be able to do a 'quick and dirty' test of the coil by running power to the positive terminal on the coil and then taking a jumper from the negative terminal and tapping it on and off quickly to ground. An old points type coil will make sparks if you do this. Anyway, no joy with the coil in the car or with the the new spare I have. Both coils test out OK with an ohmmeter.

Am I missing something?

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--> Check out my FI Turbo build <--
--> And the race truck build project <--
--> The Diesel Corvette <--

Hi! So I'm doing this with my 1977 Dodge D100 225 truck that's been giving me ignition troubles. This may be a dumb question, but do switched feeds get power during the start circuit like they do in the run circuit? It seems like they do. The reason I ask is I already have a switched auxiliary fuse panel I added that's powered from a 100AMP relay straight off the battery. In my head, it makes sense that I should be able to run the HEI module off a fuse on that feed, bypassing the old wiring and junction box completely. It would also give me the benefit of not having to cut the existing wiring harness so if it ever needed to be switched back, it could be. I'd also have the benefit of the system running of an all-new wiring system that I would know is fully functioning.

Any reason not to do it this way?

Thanks!

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Chuck and the Flying Valiant

The switched feeds for the coil and HEI module should have power in start and run. Whether they will depends on how you have wired them.

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Casually looking for a Clifford hyperpak intake for cheap.

Most all accessory power is cut during cranking. If you don't believe me then feel free to disconnect the big starter cable at the starter, turn the key to start and observe the effects. The easiest way to trigger an HEI relay is to connect both IGN 1 and IGN 2 together (already done on coil side of ballast resistor) and trigger the relay from that.

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Joshua