Hei Module issues ? Maybe. Suggestions ?

[panhead59]

1989 stock 350 ci. In a 68 p/u. (Center valve cover bolt engine) . 4K miles on engine, Summit hei dizzy, edlebrock 650 carb. (Fuel injected originally but that stuff was gone when i got engine, so i put carb on it). Amazingly dependable since rebuild. Until now. Sputtering and dieing at idle. Changed fuel filter and blew out carb. With air. Also changed hei module. Problem solved. Runs great. 1 week later broke down. $100 tow bill. No fire for ignition. Replaced with hei module that was previously installed. Ran great and "new "module proved bad with store testing. They gave me a new one. So that told me dirt in carb/filter, was sputtering issue, not module. 1 week later, yesterday, no start after sitting overnight. Luckily i was leaving work and now had a spare module with me. Changed it and ran fine coming home. 17 miles. So.... ever since i "messed" with replacing a perfectly good module, they r now going bad,(2 in a row) after approx. 1 week. Got 12.23 volts at cap. Don't suspect coil cuzz runs fine with fresh module. Yes using "heat grease" that comes with modules. Suggestions or test i can do ? I wiil return latest module, hopefully they'll give me another one. Plus i have new dizzy on the way. Truck is currently my daily driver, so pressure is on to solve this proble. Tks for any help.

[HO455]

When you did the voltage measurement was the engine running?
Do you have a tachometer? If so try disconnecting it.
I would take a close look at all the wires under the cap for damaged insulation and good connections.

[panhead59]

Measured with key on, not running. Just checked with engine running. All over the place with meter. From 3.0- 7. Jumping wildly.

[Willys_MB]

I had a similar issue recently. HEI’s have a lot more going on than just the module. I replaced my module a few times before I pulled the dizzy and tested all of the parameters. My original ACDelco module was so worn out. The end play is supposed to be very small, but mine had 10x the allowable slop. I checked a few other parameters and bought a new distributor. I haven’t looked back. I saved the ACDelco dizzy for rebuild at a later date, but I bought a $60 Chairman Mao special on Amazon and haven’t had any problems since. It’s been 6 months and I’m happy with it until I can get around to rebuilding my ACDelco.

[panhead59]

Removed cap etc. To check wires. Found the screw that holds red "pickup" loose. ( little 1"x 1/2" red block with black wire coming out of it.) Rechecked voltage. 15.5 and mostly steady while running. 12.5 with just key on. Hopefully that was the issue. 15.5 seems a little high. Don't really know. Still has 3 wire alt. And regulator. Whaddaya think ? Drive it ?

[BROWN 70]

Hi panhead, It has been stated that external regulators dont work that well with hei. I havent had any problems with mine, 5 years, also a summit. the regulator can be adjusted inside to raise lower voltage. mine was high so I adjusted it to 14.5 and it works great, so far. lol good luck, BROWN 70

[Steeveedee]

With a fully charged battery, 14.5V is about as high as I would want to see. I have an externally regulated alternator and the distributor is a 20+ year old Mallory HEI. I would adjust the regulator, personally.

[panhead59]

Ok. Took cover off regulator
I don't see any way to adjust voltage unless it's that star looking small "wheel". Mine won't turn easily so thought i'd ask b4 persuading it !!! Tks for all the info/replies.

[panhead59]

Yep, that's the adjustment. Turned it a little, showing 14.29. Think i'll leave it there. Tks 4 all the help. I'll drive her and hope all goes well !!!!

[Steeveedee]

Yeah, that "wheel" turns hard so that it doesn't rotate on its own with potentially disastrous results. My youngest brother had a '72 Dart that the (electronic) regulator failed wide open. Popped a bunch of light bulbs, overheated the battery and popped it, too. Quite the mess.

['68OrangeSunshine]

If you don't use the white heat sink paste under each new module, you'll cook them off. Also this stuff is NOT the same as white lithium lube.

[panhead59]

10 4 on the white heat sink. "Yes using "heat grease" that comes with modules." Update - took latest module to store. Checked good
Guess that loose screw by p/u rendered module useless but didn't destroy it. So at least I've got a spare and have learned a few things along the journey !!!!!! Hopefully it's fixed.

[HO455]

Congratulations on solving the problems! That's always a good feeling.
And thanks for the follow up posts. We all learn from them.

['68OrangeSunshine]

The External Voltage Regulators they sell now are sh!t. Even the USA-made ones you get as warranty trade-out from O'Reilley's. After summer of playing Mr Switch-Out, I converted the '71 GMC [350] to a 12SI internally regulated alternator. Got a brand new stock alternator for a ''1976 Blazer/350.'' Works great.
An old EVR could make some wild voltage swings, and a hot spike will kill a Module.
On my '68 C/10 [292], I cannibalized the EVR from my ''project'' '67 K/10 Suburban -- hadn't been running for 20 years -- marked as installed 9/98 -- and it started charging again. But the Standard warranty swap EVR of 8/20 was a dud. Go figure.

[RichardJ]

I hate acronyms.

Is EVR being used for external voltage regulator or electronic voltage regulator?

The original voltage regulator for the 10DN alternator is a electro-mechanical device with internal relays. It is simply known and sold as a voltage regulator.

The aftermarket now sell two types of voltage regulators for the 10DN. The original type mechanical regulator and a solid state, electronic regulator.

The solid state regulators are cheaper, lighter and very reliable. basically the same type of solid state regulator stuffed inside the 10Si and 12SI alternators.

I've been using a 10DN alternator to power a HEI with the ballast resistor wire still intact for 25 years and it has a solid state VR (stands for Voltage Regulator).

[dmjlambert]

Originally Posted by panhead59

10 4 on the white heat sink. "Yes using "heat grease" that comes with modules." Update - took latest module to store. Checked good
Guess that loose screw by p/u rendered module useless but didn't destroy it. So at least I've got a spare and have learned a few things along the journey !!!!!! Hopefully it's fixed.

Just curious, was it a grease-like substance or very thick sticky paste that is nothing like grease?

[BROWN 70]

Hi guys, when I got my summit hei I checked to see if it had heat sink compound. it didnt, so when radio shack was still open I bought a tube of heat sink compound. its a white paste, it doesnt take much to coat the module. any way I have had good luck so far. I do carry a spare module. LOL. BROWN 70

['68OrangeSunshine]

Originally Posted by RichardJ

I hate acronyms.

Is EVR being used for external voltage regulator or electronic voltage regulator?

The original voltage regulator for the 10DN alternator is a electro-mechanical device with internal relays. It is simply known and sold as a voltage regulator.

The aftermarket now sell two types of voltage regulators for the 10DN. The original type mechanical regulator and a solid state, electronic regulator.

The solid state regulators are cheaper, lighter and very reliable. basically the same type of solid state regulator stuffed inside the 10Si and 12SI alternators.

I've been using a 10DN alternator to power a HEI with the ballast resistor wire still intact for 25 years and it has a solid state VR (stands for Voltage Regulator).

External
Never tried electronic ones. Clearly they fired the QC guy, who used to set up the mechanical EVRs. He kept sending them back and that interfered with production and the bottom line.

If you're still using the 20 Yellow wire to an HEI coil, you should not be getting full voltage after it warms up. It's designed to drop voltage to 9 - 7 VDC so the points don't burn up.