Slant Six Forum :: HEI Location

Ok I have 86 Ram with Slant Six. I am going to do the HEI conversion to get rid of the leanburn system on it. Since most of the wires i need to do this conversion are running to the computer mounted behind the battery. I was going to mount it in the same location as the computer so as to make it look as stock as possible. My question is this, is this location to far from the distributor and will it make a difference in the performance of the HEI conversion, if so would using a performance module such as Accel make up the for it being so far from the distributor?

Thanks for the help.
Dave

P.S. this is a fantastic web sight lots of great information.

It MAY be that I got a bad HEI module-

My GUESS at this point is that the HEI module ... is picking up noise from the ignition secondary wiring ...

... the HEI module is almost as expensive.

Besides, it kinda grates me to have (G)enerally (M)unged parts on my Mopar anyway.

If HEI were sensitive to noise from the secondary, wouldn't it do it right under the coil, as it is in a typical GM?

Think of them as spoils of war.

So from what I am gathering here, I should either use an MSD box in the original location or move the HEI closer to the distributor. Question will the MSD work with the original lean burn distributor(no mechanical or vacuum advance)?
Again I appreciate everyones input and help, thanks very much

Dave

So from what I am gathering here, I should either use an MSD box in the original location or move the HEI closer to the distributor.

Question will the MSD work with the original lean burn distributor(no mechanical or vacuum advance)?

Why is this better than a mopar electronic iginition

Author:	xjarhead [ Thu Apr 05, 2007 10:14 am ]
Post subject:	HEI Location
Ok I have 86 Ram with Slant Six. I am going to do the HEI conversion to get rid of the leanburn system on it. Since most of the wires i need to do this conversion are running to the computer mounted behind the battery. I was going to mount it in the same location as the computer so as to make it look as stock as possible. My question is this, is this location to far from the distributor and will it make a difference in the performance of the HEI conversion, if so would using a performance module such as Accel make up the for it being so far from the distributor? Thanks for the help. Dave P.S. this is a fantastic web sight lots of great information.

Author:	SlantSixDan [ Thu Apr 05, 2007 10:49 am ]
Post subject:
There shouldn't be any measurable performance difference with the module mounted 'way over on the other side of the engine bay from the distributor, as long as it is hooked up correctly. The main thing is to make sure the module gets a quality ground and a quality metal-to-metal heat path from the bottom of the module to the mounting surface (with heat sink grease between the module and surface).

Author:	xjarhead [ Thu Apr 05, 2007 11:17 am ]
Post subject:
Thanks Dan for the reply I will make sure it gets both. Dave

Author:	440_Magnum [ Thu Apr 05, 2007 1:32 pm ]
Post subject:	Re: HEI Location
Quote: Ok I have 86 Ram with Slant Six. I am going to do the HEI conversion to get rid of the leanburn system on it. Since most of the wires i need to do this conversion are running to the computer mounted behind the battery. I was going to mount it in the same location as the computer so as to make it look as stock as possible. My question is this, is this location to far from the distributor and will it make a difference in the performance of the HEI conversion, if so would using a performance module such as Accel make up the for it being so far from the distributor? Thanks for the help. Dave P.S. this is a fantastic web sight lots of great information. For what its worth, I put together an HEI conversion a few weeks ago intending to locate the module in the same place as the Mopar electronic box that I'd put on my '66 Polara years ago. I even used an old Mopar box to mount the HEI so that they'd be plug compatible. It didn't work at all. The car would start (barely), run like poop, then die. The distributor pickup polarity was correct (reversing it would prevent the car from even starting). It MAY be that I got a bad HEI module- I've never bothered to go back and finish trouble-shooting it or replacing the module. I can tell you its definitely not a power or grounding issue, I did get that far. My GUESS at this point is that the HEI module cannot tolerate the long run from the distributor pickup to the module, and is picking up noise from the ignition secondary wiring causing false triggering. After all, an HEI module made to be mounted inside the distributor and right next to the pickup. I would be VERY interested in hearing whether you get it to work or not. I'm not highly motivated to go back and figure it out at this point. There's not that significant of a performance or reliability gain over Mopar EI, and the HEI module is almost as expensive. About the only real advantage is getting rid of the ballast resistor. Besides, it kinda grates me to have (G)enerally (M)unged parts on my Mopar anyway.

Author:	slantvaliant [ Thu Apr 05, 2007 2:04 pm ]
Post subject:	Re: HEI Location
Quote: It MAY be that I got a bad HEI module- Quite possible. Pick up a couple at the junkyard for testing and spares. Quote: My GUESS at this point is that the HEI module ... is picking up noise from the ignition secondary wiring ... If HEI were sensitive to noise from the secondary, wouldn't it do it right under the coil, as it is in a typical GM? Quote: ... the HEI module is almost as expensive. They're pretty cheap at the junkyard, from Chevy-based friends, etc. Mine came free. The HEI modules are smaller, taking up less space in my roadside spares box, especially if you add in the volume of the ballast resistor. Quote: Besides, it kinda grates me to have (G)enerally (M)unged parts on my Mopar anyway. Think of them as spoils of war.

Slant Six Forum https://slantsix.org/forum/

HEI Location https://slantsix.org/forum/viewtopic.php?t=22589	Page 1 of 2

Author:	xjarhead [ Thu Apr 05, 2007 6:23 pm ]
Post subject:
Thanks everone for the replys. It will be a few weeks before i get a chance to do this swap. I will post the results. Thanks again Dave

Author:	440_Magnum [ Mon Apr 09, 2007 10:19 am ]
Post subject:	Re: HEI Location
Quote: If HEI were sensitive to noise from the secondary, wouldn't it do it right under the coil, as it is in a typical GM? A very fair question, but its not really easy to come up with a straightforward answer. The thing to consider is that the trigger mechanism is a DIFFERENTIAL signal. If it were single-ended (like the radio antenna on the car which picks up an electric field) then yes, putting it right near the coil would be horrible. But its doesn't work that way, the pickup pushes a current through a loop of wires and the module senses that current and detects when the current reverses direction in order to fire at the right time. Given that condition, a long PAIR of wires is more sensitive to pickup because the magnetic field generated from a coil or plug wire can cut through the gap between the wires and put noise on the signal. A tightly twisted pair of wires would help mitigate the problem, but the standard Mopar connector is anything but a tightly twisted pair- the wires are about 1/4 inch apart at the connector, even if you twist them everywhere else. Quote: Think of them as spoils of war. I like the way you think.....

Author:	xjarhead [ Tue Apr 10, 2007 9:35 am ]
Post subject:
So from what I am gathering here, I should either use an MSD box in the original location or move the HEI closer to the distributor. Question will the MSD work with the original lean burn distributor(no mechanical or vacuum advance)? Again I appreciate everyones input and help, thanks very much Dave

Author:	440_Magnum [ Tue Apr 10, 2007 10:32 am ]
Post subject:
Quote: So from what I am gathering here, I should either use an MSD box in the original location or move the HEI closer to the distributor. Question will the MSD work with the original lean burn distributor(no mechanical or vacuum advance)? Again I appreciate everyones input and help, thanks very much Dave Don't rule out your plan yet, go ahead and try it- mine could EASILY just be a bad HEI module and I will try another one one fo these days.

Author:	Matt Cramer [ Tue Apr 10, 2007 12:36 pm ]
Post subject:
Quote: So from what I am gathering here, I should either use an MSD box in the original location or move the HEI closer to the distributor. My HEI module is mounted on the inner fender, about where a Mopar ignition box would go. It hasn't given me any problems working there. I am using a seven pin HEI module with a Lean Burn distributor, but this is an injected motor with Megasquirt controlling the timing. Quote: Question will the MSD work with the original lean burn distributor(no mechanical or vacuum advance)? Not very well, if this is on a street car with no added electronics. The Lean Burn pickup will fire a MSD box, but at a fixed timing. To get this working right, you'll need some sort of timing control computer. This one would work pretty well if you used it with an MSD box and Lean Burn distributor. The biggest drawback is that it's a 2D system, with RPM based control but no vacuum advance, which would be helpful for drivability and mileage. A Megasquirt can also be set up as a timing computer. You can have it read the Lean Burn distributor pickup directly and fire the MSD box if you go with a V3.0 board, and it does correct for vacuum. They are a bit more complex to set up, however.

Author:	xjarhead [ Tue Apr 10, 2007 5:25 pm ]
Post subject:
Thanks Matt I will try it and see what happens. It will be a while before i get to do it but i will post the results. Dave

Author:	xjarhead [ Mon Apr 23, 2007 1:34 pm ]
Post subject:
With this conversion I am looking at useing the Petronix Flamethrower module, #D2000 $39.88 at Summit Racing and the Flamethrower 60,000 volt coil #60104 64.69. With this combination how wide of a gap can I set and would I have to go to a different plug range? Maybe cooler? Thanks Dave

Author:	SlantSixDan [ Mon Apr 23, 2007 6:13 pm ]
Post subject:
Use an MSD Blaster 2 coil ($45 at Summit), not a so-called "60,000 volt" item; see this thread. There's no need or reason to use other than a stock HEI module (NAPA Echlin TP45, Standard-Bluestreak LX-301), either. NAPA Echlin long-tip rotor # MO-3000, Standard CH-410X cap, plug gaps at 0.045", heat range to suit parameters of your particular engine.

Author:	Ron Parker [ Mon Apr 23, 2007 6:24 pm ]
Post subject:
Why is this better than a mopar electronic iginition. Some one tell me. Thanks Ron Parker Bagels On Juice Im On Boost

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Author:	SlantSixDan [ Mon Apr 23, 2007 7:41 pm ]
Post subject:
Quote: Why is this better than a mopar electronic iginition This post contains a detailed technical comparison of the two systems. In short, the HEI gives a hotter, longer-duration spark and eliminates the ballast resistor.