Slant 6 HEI

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TechMavn

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hi there friends I have used HEI systems on my projects. i am looking for any thoughts on a 1 piece HEI (coil in the cap) for my 70 Duster 225 project. have seen a lot of discussion out there on different types, but do not want to run a separate coil. anyone try this recently with current suppliers that generated a good result ? thank you for any thoughts !
 
I think that a GM style coil in cap might be too big to fit on a slant block. I could be wrong, but the ones I recall were huge compared to a 'standard' style distributor.
 
No way is there anywhere near enough room for coil-in-cap on a Slant-6. Optimal parts selection is discussed in the HEI upgrade article, and as far as caps and rotors go, read and follow the suggestions in this long (but worthwhile) thread.
 
I agree about the room. That's probably why I've never seen one for a slant six engine.
 
TechMavn said:
hi there friends I have used HEI systems on my projects. i am looking for any thoughts on a 1 piece HEI (coil in the cap) for my 70 Duster 225 project. have seen a lot of discussion out there on different types, but do not want to run a separate coil. anyone try this recently with current suppliers that generated a good result ? thank you for any thoughts !
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Personally I HATE the big cap / coil-in-the-cap HEI distributors. Since they are completely unitized, they are much more difficult to diagnose. About all you can do, other than a few simple resistance tests, is shotgun parts at them. Either that or "rig" a harness so you can separate the parts for testing.
 
slantsixdan said:
No way is there anywhere near enough room for coil-in-cap on a Slant-6. Optimal parts selection is discussed in the HEI upgrade article, and as far as caps and rotors go, read and follow the suggestions in this long (but worthwhile) thread.
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yikes, a lot of reading here. have seen a HEI made by a Mopar distributor that looks decent, have some follow up to do but is not a name brand:
eBay (ebaydesc.com)

thank you for the thoughts!!
 
67Dart273 said:
Personally I HATE the big cap / coil-in-the-cap HEI distributors. Since they are completely unitized, they are much more difficult to diagnose. About all you can do, other than a few simple resistance tests, is shotgun parts at them. Either that or "rig" a harness so you can separate the parts for testing.
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correction, is electronic but doesnt appear to be HEI... thank you
 
That distributor is from Rick Ehrenberg of Mopar Action magazine. He sells several custom parts for Mopar engines, though rather pricey. For my 1964 Slant, I used an 8-pin HEI module (1985-95 GM V-8 trucks) with its coil and cable connecting the two. Also grab the GM pickup connector. The sealed Weatherpack connectors are nice. I ran a temp cable to the Mopar e-distributor (1971+) since I haven't verified pickup polarity. I will use a timing lamp to verify it sparks when the reluctor teeth are aligned. Note you want twisted cable. I will make that purtier. Haven't run the engine yet, but same setup in my 1965 Chrysler which runs fine. There I have a Holley Commander 950 to adjust spark timing via a cable to the 5-pin connector on the HEI module (not required).

The other things on the inner fender are the Vreg since smarter to have it near the alternator. Also, a home-rigged heater cut-off for when my knee-knocker AC is running. The water valve is for a Ford ($9 ebay) and junkyard vacuum switch from a 1980's Dodge. I use silicone hose wherever I can (lasts forever).

HEI-small.jpg
 
BillGrissom said:
He sells several custom parts for Mopar engines, though rather pricey.
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His ENTIRE electronic ignition kit for the slant six is like 150 bucks. That's hardly what I call pricey.
 
BillGrissom said:
That distributor is from Rick Ehrenberg of Mopar Action magazine. He sells several custom parts for Mopar engines, though rather pricey. For my 1964 Slant, I used an 8-pin HEI module (1985-95 GM V-8 trucks) with its coil and cable connecting the two. Also grab the GM pickup connector. The sealed Weatherpack connectors are nice. I ran a temp cable to the Mopar e-distributor (1971+) since I haven't verified pickup polarity. I will use a timing lamp to verify it sparks when the reluctor teeth are aligned. Note you want twisted cable. I will make that purtier. Haven't run the engine yet, but same setup in my 1965 Chrysler which runs fine. There I have a Holley Commander 950 to adjust spark timing via a cable to the 5-pin connector on the HEI module (not required).

The other things on the inner fender are the Vreg since smarter to have it near the alternator. Also, a home-rigged heater cut-off for when my knee-knocker AC is running. The water valve is for a Ford ($9 ebay) and junkyard vacuum switch from a 1980's Dodge. I use silicone hose wherever I can (lasts forever).

View attachment 1715639075
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quite a rundown thank you for the details. im more a hobbyist , dont have the experience to do myself...
 
$150 for a Mopar ECU kit isn't bad, considering others were asking >$250 on ebay a few years ago. But, I still wouldn't go that route since it is much more rewiring effort only to realize an outdated electronic ignition system. I was thinking more of Ehrenberg's parts like his custom reluctor wheel for the Mopar distributor. At least for V-8 owners, a complete ready-to-run distributor for $45 seems better. Too bad Ningbo doesn't make such a distributor for the slant.
 
TechMavn said:
... dont have the experience to do myself...
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I wouldn't conclude that until you look at the many posts which document the HEI wiring. If you look closely at my photo in post #8, the connections are simply:
Red wire to +12 V IGN power
Ground wire to HEI mounting bolt (or just rely on the mounting bolt, but I didn't)
2 wires from Mopar e-distributor to HEI
Plug the GM cable from the HEI to the GM coil
Done

There is a white tach wire you can send to a cabin tachometer display, but not required.
There is a 5-pin connector for spark advance command, but not required.
 
BillGrissom said:
$150 for a Mopar ECU kit isn't bad, considering others were asking >$250 on ebay a few years ago. But, I still wouldn't go that route since it is much more rewiring effort only to realize an outdated electronic ignition system. I was thinking more of Ehrenberg's parts like his custom reluctor wheel for the Mopar distributor. At least for V-8 owners, a complete ready-to-run distributor for $45 seems better. Too bad Ningbo doesn't make such a distributor for the slant.
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How is it outdated with a hot ignition curve? Also if you add the FBO total timing limiter? Outdated? Dated, maybe, because it's been around a long time, but that doesn't make it inferior.

The only real trouble with the Mopar style electronic ignition system is the fact that quality replacement parts are getting hard to find. People like Eherenberg and FBO are changing that.

Can you please point to valid, unbiased data showing how the Mopar style system is inferior when using good quality parts?
 
RustyRatRod said:
How is it outdated with a hot ignition curve? Also if you add the FBO total timing limiter? Outdated? Dated, maybe, because it's been around a long time, but that doesn't make it inferior. ...
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You discuss spark timing. That is a separate issue than spark intensity and is controlled by the distributor, so is independent of what ECU is used. The Mopar ECU requires a ballast resistor, as do some other early electronic ignitions (even after-market Crane Cams XR700). GM's HEI came out about 5 years later and has superior electronics. HEI controls dwell, so no need for a ballast resistor. Dwell is how long the coil is "charged up" before the next spark. It also uses an e-core coil, which gives a better spark. The Mopar ECU is "good enough", but as I clearly stated, it is much more work to wire it into an early points car than the GM 8-pin HEI, so why go thru more work for a poorer system? If your car came w/ the Mopar ECU (1971+ or so), smart to keep it as long as you can still get quality parts.

You can find youtubes of various spark systems. Perhaps the best factory system is GM's LS coils. Like most, they use a separate coil per cylinder. But, that requires crankshaft and camshaft sensors and a controller to command the sparks. The Megasquirt site has much info.
 
BillGrissom said:
You discuss spark timing. That is a separate issue than spark intensity and is controlled by the distributor, so is independent of what ECU is used. The Mopar ECU requires a ballast resistor, as do some other early electronic ignitions (even after-market Crane Cams XR700). GM's HEI came out about 5 years later and has superior electronics. HEI controls dwell, so no need for a ballast resistor. Dwell is how long the coil is "charged up" before the next spark. It also uses an e-core coil, which gives a better spark. The Mopar ECU is "good enough", but as I clearly stated, it is much more work to wire it into an early points car than the GM 8-pin HEI, so why go thru more work for a poorer system? If your car came w/ the Mopar ECU (1971+ or so), smart to keep it as long as you can still get quality parts.

You can find youtubes of various spark systems. Perhaps the best factory system is GM's LS coils. Like most, they use a separate coil per cylinder. But, that requires crankshaft and camshaft sensors and a controller to command the sparks. The Megasquirt site has much info.
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No offense meant Bill, but all of this is your opinion. I'l agree that perhaps the LS coils are better. One coil per cylinder is probably as good as it gets "for now", but comparing all of the different electronic distributor ignitions and the Mopar unit is as good as any.
 
TechMavn said:
what is difference between 1970 ECU and 1971 and after ?
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are you talking about mopars electronic ignition or chevys hei? I personally have ran all of them, i ended up getting a used MSD unit on ebay the older 6A box works great. If you also find a broken unit MSD repairs them for $49.95
 
Slantsix64 said:
If you also find a broken unit MSD repairs them for $49.95
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Not all of them. I had a MSD 7 that quit working. I called MSD to inquire about repair, and after giving them the serial number, was told "to old (bought 1976), can't even get parts". Someone on slant six.org offered to take a look at it, for me. He replaced one transister, total cost $25. Been working fine for over 5 years now.
 
Actually a stocker Mopar coil gives a LOT hotter spark with a GM module than it does with a Mopar, so using a stock coil is not necessarily a bad thing "on a budget." I don't discount that there are better coils.
 
TechMavn said:
hi there friends I have used HEI systems on my projects. i am looking for any thoughts on a 1 piece HEI (coil in the cap) for my 70 Duster 225 project. have seen a lot of discussion out there on different types, but do not want to run a separate coil. anyone try this recently with current suppliers that generated a good result ? thank you for any thoughts !
Click to expand...

I am brand new here, David Ray, owner, tech, developer and tech, DAVE's small-body HEI's. This IS NOT AN AD, it is simply info.

I worked for Zora Arkus-Duntov in Skunk Works for a few years, engine design developer. and was lent to the group that designed and developed the large, coil in cap HEI's to help develop them.

About 42 years ago, I designed and now build my own version of the GM module HEI. One factor on the coil in cap HEI is the coils are severely problem prone, they start to fail, and take module after module out as they slowly fail. That is what you get with an epoxy filled coil, problems. If you know someone that has a large coil in cap HEI, and has module failure issues, change the coil, i is on the way out, slowly. Round remote oil filled coil is the only way to go, mounted upright, not on its side.

I do MOPAR conversions a bit differently, I build one of these, MSD Trigger Only, small-body real HEI, EFI-HEI with 8 pin GM HEI modules, EFI-HEI for Sniper/FiTech EFI. The Ford/MSD pickup is a lot more stable than a MOPAR pickup, but the stock pickups do work, to a point.

I have done a lot of Direct Connection conversions, swapping in a Ford/MSD magnetic pickup, and changing the mounting plate to move concentric with the reluctor, so signal strength is not compromised, as it is with the less effective MOPAR pickups that change gap as they move past the reluctor pole centers from eccentric movement.

ALL conversions are done to stock point and MOPAR electronic cores, NONE of them use an in cap coil, and all parts are stocked at local parts stores, like O'Reilly's. The real HEI's use the 4 pin GM HEI modules, the EFI-HEI uses the GM 8 pin modules, straight off the parts shelves. During a conversion, I completely rebuild the distributor and curve it, as part of the conversion.

Decades ago, I did one for my own Hyper-Pak, 4 speed Slant 6 in my Duster.The worst problem with the stock distributor is the plastic gear, they fail. I understand there are new design, new materials gears available, they should help immensely.

As I said THIS IS NOT AN AD, just saying hello, and that I am well aware of the one real HEI conversion available. And, the drop-in points replacements, are not HEI, they have NO dwell extenders and do not make any more spark energy than a stock set of points, no matter the input voltage to the module and coil, nor the coil used.
 
David Ray, welcome to the swamp. I think you will be a handy guy to have around.

I don't know why, but history intrigues me. When something interests me I usually research the hell out of it. That's why I have a fairly extensive collection of books on Chrysler history. WPC, the 3 Musketeers engineering team, Ramchargers, etc. One thing that stands out is that the old Chrysler Corp was founded on solid engineering. They researched, engineered, tested and implemented a lot of advancements including electronic ignition. In the fall of 1971 we ordered a new 1972 Satellite Sebring Plus. Electronic ignition was standard on the hi-po engines but was an option on a 318 so I checked it off on the order form. I have NEVER owned a GM product but occasionally used to work on friend's cars. It was eye opening because to me GM seemed to take the cheaper way out but Chrysler would spend the money to make a more durable product. However, I was jealous of the sliding door on the GM points distributors that allowed external dwell adjustments.

Now to the Slant six...one of the few weak points is the oil pump drive geared to the cam shaft. This is well documented at www.slantsix.org
Yes the nylon distributor drive gear fails, also driven by the same camshaft gear as the oil pump. But knowing, observing and analyzing the thinking of the anal retentive Chrysler engineers, I believe the "weak" nylon gear was intentional and acts as a sacrificial shear pin. If there is a problem, the nylon teeth shear, stopping the engine like right now. Yes, a bronze gear would be more durable but suppose the oil pump gear outlasted the distributor gear? The oil pump would stop and the engine would continue to run without any oil pressure.

People tend to forget the Slant Six was designed in the late 50s so it's easy to compare It to what we're used to seeing 60 years later.

******

My personal experience is when I rebuilt my 1964 225. The nylon drive gear was discolored and cracked through the pin hole so I replaced it with a new gear sourced from NAPA. I think it was sbout $4. I keep a spare in my trunk box because I drive the car to out of state shows. The car had 97,000 miles on it and had been in storage for about 32 years when I started so not too bad.
 
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@David Ray welcome! I did a web search and checked out your website after your interesting post... What I want to know is (off topic)... WHAT THE HECK BIT YOU TO MAKE YOUR HAND LIKE THAT!!! (in the gallery photos)
 
theFightingFew said:
@David Ray welcome! I did a web search and checked out your website after your interesting post... What I want to know is (off topic)... WHAT THE HECK BIT YOU TO MAKE YOUR HAND LIKE THAT!!! (in the gallery photos)
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I'm guessin a brown recluse.
 
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