Technical My car has an HEI, can I ask a tech question here?

I know HEIs aren't exactly period correct...

 

Oh, no, no no. Ask your question. Then maybe the mods will let is stay-or maybe someone will answer before it is deleted.. No one knows if your question is okay until you ask it!

 

Driving my dads '34 "Chevy in a Ford" coupe and the motor/juice just dies about a mile from the house. (Enough time to get up to temp etc). Older battery we've been limping along. Had to get it jumped. Get back to the house and it dies pulling into the garage.
About a week and a half later I go buy a new battery, cause I figure it's time. Put the new one in. Take it for a spin. (Not as far this time ;-) ) and the same thing happens, only this time ,because the battery is fresh, I turn off the key, turn it back on and she jumps back up and I drive off. Happens a second time on the way home, only this time I'm running down a hill so I'm coasting, slip her into neutral, turn the key off and on, hit the starter and she jumps back up again and I make it home.

Running all the things through my brain,
as long as the key stayed on after it died, there was no juice
Second session, if I turned the ignition off and back on, the juice would come back up and it would start right up.

Can't be vapor lock, it starts right back up.
It's got fuel, it's got air, it's gotta be electrical, right?
Voltmeter says it's charging aroun 12-14 while running in motion.

Can the guts in my HEI be crapping out?
Could it be something to do with the temp relay for my electric push fan? (I know, sin number two). Could it be that when the car gets up to temp and the fan tries to kick on that something happens to kill the juice? Electrical is not my strong point obviously.

Any feed back would be greatly appreciated.
Thanks guys
Terranova

 

Hei module going bad . just happened to me a few months ago just like you describe.

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Thanks man, appreciate it. I gotta do more reading up on the HEI thing. My dads buddies decided it was more reliable for my 70 year old dad when we built it.

Thanks again T

 

I'm thinking you should drive it let it die. Don't touch anything. Get stopped safely. Don't touch anything. Raise the hood take the test light and see if you have power on the red wire feeding the HEI. No power. Go back inside turn the key off and back on. Check the red wire. If it has power I m thinking it's the switch. That's just my opinion and it didn't cost you a dime.

 

Mine did the same thing a while back. Missing ground strap inside the HEI causes the internals to short out, dying a slow painful death. Here's a thread that I put together (with pics) to explain it.

https://www.jalopyjournal.com/forum/threads/stupid-hei-tech-for-dummies.950499/

 

Mine did that and I put in a new ignition switch and it hasn't done it since.

 

"Chevy in a Ford"
Organ rejection, it happens...

 

325's advice is where you should start. While the module may be going bad, I also would start with the ignition switch check to make sure you are getting constant power to the HEI. May be as simple as a wire loose or frayed. Follow the current into the ignition and then back out to the HEI.

 

I, as well, would recommend looking at everything in the circuit that powers and grounds the module. HEI modules are fairly robust. That is not to say that they don't go bad, but there are/were literally millions of them in-service. I even have one on my 6-cylinder Falcon. Not exactly super famous for being hella fragile.

 

Same thing happened to a buds car out on the turnpike. I had a ice chest with me. Put a baggie of ice on the distributor. Made it another 60 miles to parts store. Might be a good way to check out the HEI.

 

Caused by hot-air blowing over the engine block and cooking the Dizzy, you need to swap in an engine with a front mounted dizzy

A faulty coil would cause the same symptons.
Does your car have a Tacho?
An ignition feed issue or a faulty module will cause the Tacho to flicker

 

Get a voltmeter and temporarily connect it to the positive feed on the distributor, and mount it inside the cabin (just leave it on the floor). Keep an eye on it when this all happens, it will tell you wether its the switch or the distributor.

 

I wanna see that "Chevy in a Ford".....

 

Most ALL Fords have Chevies in 'em. Couple of mine do...

 

The five in my garage sure as hell don't

 

HEI and other electronic items fail in strange ways.
Sometimes they act fine until they "warm up".

QUICK TIP - if you want to make an HEI module last a whole lot longer, MOVE IT TO A COOL LOCATION.
I got tired of changing HEI modules every few years, sometimes in a far away parking lot.
Once I located my new module under my dash inside the car by running wires from the distributor with the idea that I wouldn't have to climb under the hood to change it next time.
In that cooler location I haven't had an HEI failure in over 15 years.

why be ordinary?

 

The first thing I would check is the pick up pole.( some call it pick up coil). Check the wires that go to the module, over time they get brittle and break inside the insulation. If you pull on the wire you will feel the break or it will break all the way through. When the vacuum advance moves it stretches the wire and breaks the connection. Then when you lose vacuum it moves back and that is why it will start again.
Try brake torque and see if the ign breaks up and start to miss under load
This was common back in the 70s and 80s before ecm controlled the advance
If is good then replace the module and coil as a set.

 

By the way, I used to build HEI distributors for AMC, JEEP, Packard, Studebaker,....
I even shipped a boxful of HEIs built for Hudsons to Clifford Performance years ago.
The weak area is in the module not getting enough cooling.
Move the module to a cool place and they last a long long time.

My daily driver is still running an HEI I built for it over 25 yrs ago.
Keep it cool.
photo - it will light up a room if you want it to.

P.S. my Suzuki hot rod bike uses two hei modules and high output coils as does my ski boat



why be ordinary?

 

Lots of good ideas already mentioned, one more, if it has a tach that shorts when hot it will ground out signal, Unplug tach from dist. and drive for test.

 

There was no juice where..and how do we know this?

 

Good point Mark yac
I missed that

 

Very closely inspect the wires inside the dist as the insulation cracks and can short it out. Also wires at the module crack and break which disrupts the voltage to/ from it.

 

This happened to my '62 Chevy.. please cut me some slack with how stupid I'm about to look with my lack of correct terms but the little "nipple" in the center of the cap that the rotor turns on was broke...


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Two things not covered are...
Sometimes the rotors have a hole burned through the center.
I was told by a mechanic older than my 50 age, that when spark plug wires get old and build resistance, the HEI module has a tendency to break down.
To the naysayers, just like the old days to use an ohm meter to check for resistance and continuity breakdown. Simple troubleshooting.
I'd rather see a car built in our favor by somebody that cares, than to see the crusher send it out as scrap. $$$$ drives many a build, including mine.

 

See? There you go. Lots of good folks on the HAMB

 

Well I was going to suggest the Ford was Trying to take a dump and Pass that Chevy Trash.........

 

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