HEI Ignition
 

I'm helping a buddy with putting an HEI distributor in a V8 A-body. Actually, he's already installed it but he hasn't hooked it up properly. I think I've figured it out but I'm not that familiar with the circuits so I'm hoping that someone can tell me how to power the unit.
He was having issues with it, so I told him to hook it up right to the battery with a toggle switch. Runs fine. I asked him what he did before that and he said that he put a connector on the end of the power wire for the HEI and plugged that into an available IGN blade at the power block. I believe that was his problem? When he turns to key to start, doesn't it kill the power to that terminal?
If this is the case, how do you hook the thing up without buying a new HEI modified harness from M&H?.

What year of car?

Generally, I'd say the 'IGN blade' would probably not have power when the key is cranking?

I also would say the normal resistance wire for the ignition is from the junction box on the engine side of the firewall to coil. Changing that wire to a regular type of wire would provide the 12 volts as opposed to 9/10 volts normally.
(so the aftermarket wiring would be for the engine side)

:)

Sorry, I should have specified that it’s a ‘66 Chevelle.
Thx

In any case, the resistor (wire or block type) should be bypassed for operation with HEI. Since it's an "A" body, GM probably used a resistance wire similar to Pontiacs. Once the resistor is bypassed, The IGN2 circuit feeds the HEI when starting, and the bypass connection feeds it when running.

Usually connecting IGN2 to IGN1 at the ignition switch will do the same thing as a resistance bypass. When IGN1 becomes live in the run position, the HEI current goes to the HEI thru the IGN2 wire, automagically bypassing the resistance.

The above is only for cars with an IGN2 circuit from the ignition switch. Some GM cars like "F" body Pontiacs, use a wire from the starter solenoid to the distributor to provide power when starting. Obviously since there is no Ign switch IGN2 circuit, the connection mentioned above is not valid. On those, the additional bypass wire should be used.

george

Ok I understand. He ran a simple wire to the fusebox, but without an IGN 2 connection somewhere, forget it. It's not starting. Thanks for that.
So really, all I have to do is go over there and find the IGN2 wire that is supposed to go to the distributor and splice it into his new wire, correct? He can leave his new wire plugged in at the power block as it is effectively an IGN1 circuit. The original resistor wire will be redundant and coiled up under the hood or cut off.
To do it correctly, I guess that it's best to pull the resistor wire location and run a regular wire, but I'm not enthused about pulling the 53 year old harness end at the firewall and screwing around with it.

If the original IGN2 wire to the previous coil + terminal is intact, connect this wire to the HEI BAT terminal. There are now 2 options: 1). replace the IGN1 resistance wire with a 12 gauge wire from the start of the resistance wire, (usually on the engine side of the fuse block, to the HEI BAT terminal also. 92 wires now on the BAT terminal).

option 2: Under the dash or at the fuse block, connect IGN1 and IGN2 together. This way you only need the previous IGN2 wire going to the HEI BAT terminal.

Again, this is for a car that has the IGN2 circuit from the ignition switch and the resistance wire is under the hood. Cars with the resistance wire under the dash will require the resistance wire bypassed or a IGN2 to IGN1 connection at the ignition switch.

george

Add L6 powered Pontiacs to your list. Every one of them I've worked on used the chevy style IGN-2.

More times than not, chevy V8 cars used the starter solenoid 'R' terminal for IGN-2/cranking power. On some of those, the only hot wires at the ignition switch, while cranking, was battery and solenoid wire. Add a mini starter along with HEI, and you had to use diodes and relays for starter solenoid and/or HEI.

Clay

Sorry I am late to the party, but here is what I did to make the conversion to HEI from the original breaker point system.
There is a PINK wire coming from the ignition switch. It is a full 12 volts during cranking and during the run positions. Tap/splice into that wire and run it to the HEI. The original only provides 9.? volts to the ignition and the HEI needs a full 12.? to operate. This was very simple and works well.

This is what I do.

Thanks, that does sound simple.

PerTronix Flame-Thrower HEI Distributor - Has Anyone Run one?
 

Has Anyone Run a PerTronix Flame-Thrower HEI Distributor - If yes, how do you like it? Has it been reliable? Have any electronic module failures?
Do you like the performance? Thanks much, Tom R

It's best to use a switched relay to wire 12 volts to the distributor. You can wire the coil of the relay to a ignition switched wire. The original coil power wire has a resistor build-in so you can't use that to feed the HEI.

Fusing, or, using a relay to power up an ignition system is not the way to go.

Direct connect to a full voltage source, hot in both start and run IS the way to do it.

If the IGN isn't hot only in both start and run, the R terminal on the starter solenoid can be used, as the stock point system used it, to get power to the coil for start, then, run the IGN wire for run.

There are bulkhead fitting wire terminals available through GM dealers to change their ends in the connector, use them if you swap wires at the bulkhead connector.

May I ask what spark plugs and gap you decided on your pontiac motor with the hei conversion?

I went with .040

I have used one of Davids SBHEI for years with no issue.I have also used the Pertronics (knock on wood) with no issues.Tom

Tjs72Lemans. Are they R45S plugs?

Yes.

Thank you.