My $25 stock appearing HEI conversion

[boydsdodge]

Why not just stick a new mopar ECU in and be done with it?

[Justins72]

reason I want to go with the HEI module is because of the clean looking firewall with no ecu and ballast. Also not sure if its related to the electrical but for some reason after driving the car around for awhile and it heats up. When I shut the car off it will not start until it cools down, it will crank over but not fire.

[nqkjw]

Why not just stick a new mopar ECU in and be done with it?

Because the mopar ECU was good in it's day but it's day was the 70's.

HEI is better,less complicated,more reliable,easy to set up and cheaper.

Just makes sense to modernize to something better unless it's a 100% original resto.
Sort of the same way some upgrade brakes,suspension,engines,etc.

[UKcuda]

...........for some reason after driving the car around for awhile and it heats up. When I shart the car off it will not start until it cools down, it will crank over but not fire.

It's annoying when they do that because there are a few different things can cause it.  I reckon a good place to start is check and clean up the battery clamps, the big earth strap connections and the connections on the way to the starter.  It doesn't cost anything and I have found a couple of times it has cured hot start problems without having to do anything else.

[Justins72]

It's annoying when they do that because there are a few different things can cause it.  I reckon a good place to start is check and clean up the battery clamps, the big earth strap connections and the connections on the way to the starter.  It doesn't cost anything and I have found a couple of times it has cured hot start problems without having to do anything else.

Whats the Earth strap? All other connections are new as I relocated the battery to the trunk and nothing has changed from it being in the engine compartment or the trunk. I know sometimes when It wont start if I change the ballast with an extra it starts up fine. I don't know if that coincidence or the problem. Sometimes it just leaves me stranded in parking lots for hours, its done that twice once it got towed and the other started up while on the phone with the tow company.

[UKcuda]

Well the ballast is bypassed anyway on cranking so sounds like coincidence, unless there's a dodgy connection round there.

Earth strap is what I call the earthing cable/s to the engine.

[Justins72]

I went through the summit site and i think I figured out what coil and module I will be using.
module http://www.summitracing.com/parts/MAA-607/
coil http://www.summitracing.com/parts/MAA-30440/

[UKcuda]

I went through the summit site and i think I figured out what coil and module I will be using.
module http://www.summitracing.com/parts/MAA-607/
coil http://www.summitracing.com/parts/MAA-30440/

I think that's the same module I used on my 'cuda (and it was from Summit).

That coil should be good.  You really don't need to spend that much but I suppose you do get a bracket and connector with that one.

[abodyjoe]

Has your challenger got a factory tach ?

My tach reads a bit funny with the HEI.  I've seen references to a "filter" you can put in line with the tach wire but I'm not sure what it is - I suspect it could be just a big zener diode or some other quite simple thing.

  you think you would have the tach problem with an aftermarket tack?  just wondering because i'm going to try the HEI. i have an autometer tach and was wondering if thats something i would have to do also.   think i'll spend the cash on that bracket for the distributor though.   i like the idea of it being out of the way on the distributor and no ecu on the fenderwell...

 any of you that have changed to the HEI feel any performance gain? easier starts or anything? or is all you get is the reliability and easy to find module? if all i get is the reliability and easy to find parts thats cool with me. but performance gain would be an added bonus.

[UKcuda]

You might have a problem with your aftermarket tach. you'll just have to try it and see.

I solved my tach. problem with a diode and resistor in series with the signal wire.  If it's not in this thread just search for "diode" and it will probably come up.

I have this system on two cars and they both definitely start better with it.  I'm not sure about any performance increase, it probably depends how good/bad your old system is. 

I've had no reliability issues at all, which is nice, though I do still carry a spare module just in case.

[Strawdawg]

I think mine starts better and idles better...the latter probably due to the wider plug gap or the variable dwell in the module.

[nqkjw]

My slant 6 Valiant ute definitely starts heaps easier.
As for performance it's hard to say as it's just a stocker with 4bbl and headers and tops out at only 4500rpm.
It's got a cheap Autogage tach in it and no problems.

My 440 challenger is all new so I don't really have a "before" to compare it against and haven't done many miles in it.
But it starts easy,revs clean and appears to do everything right.
Only last weekend I fitted an Autometer Phantom 3 3/8" tach to it which works fine but with one small glitch.
When held at around 1500rpm the tach does an occasional spike to abt 1800rpm but no change to engine note.
I had a mate who's clued up on electronic stuff have a look at it and he feels it's what he calls feedback.
That is , The tach wire is picking up an inductive signal from an adjacent power wire somewhere.
Anyway,if he's right it means it's not an HEI issue.

[ShelbyDogg]

Only last weekend I fitted an Autometer Phantom 3 3/8" tach to it which works fine but with one small glitch.
When held at around 1500rpm the tach does an occasional spike to abt 1800rpm but no change to engine note.

Reverse the wires that come from the pickup to the HEI modules then re-time the car with a timing light. Those spikes are actually causing a spark and could damage the engine.   Tell your "electronic guy" that it has to do with the rising edge or falling edge of the generated sine wave that the VR sensor is putting out. If your HEI module is triggering on the wrong edge, you get extra triggers and your coil puts out extra sparks.

[nqkjw]

Reverse the wires that come from the pickup to the HEI modules then re-time the car with a timing light. Those spikes are actually causing a spark and could damage the engine.   Tell your "electronic guy" that it has to do with the rising edge or falling edge of the generated sine wave that the VR sensor is putting out. If your HEI module is triggering on the wrong edge, you get extra triggers and your coil puts out extra sparks.

Thanks for the info.
It's way over my head but my mate will understand what you're saying.

[UKcuda]

Thanks for the info.
It's way over my head but my mate will understand what you're saying.

Triggering the wrong way round can also affect the idle quality so watch for a smoother idle when you swap it round which will confirm it was the wrong way, if you find it actually idles worse that would suggest you had it right the first time and perhaps something else was indeed causing the tach. to jump.