Would anyone have, or know what model of hei distributor would fit in my 84 iron duke 4 cylinder engine? I am trying to migrate away from the factory ecm. I've successfully replaced the stock throttle body with a Holley Sniper unit, and it's working great. Now I'd like to remove the old computer controlled distributor, and install something like a 74 to 82 hei distributor that has the mechanical, and vacuum timing advance mechanics. I think my timing is jumping around, and I'd like to just set it, and eliminate that from my tuning. I'm thinking something like an 82 Sunbird, or the like might be what I'm looking for. Just seeing if anyone else has explored this.
Would anyone have, or know what model of hei distributor would fit in my 84 iron duke 4 cylinder engine? I am trying to migrate away from the factory ecm. I've successfully replaced the stock throttle body with a Holley Sniper unit, and it's working great. Now I'd like to remove the old computer controlled distributor, and install something like a 74 to 82 hei distributor that has the mechanical, and vacuum timing advance mechanics. I think my timing is jumping around, and I'd like to just set it, and eliminate that from my tuning. I'm thinking something like an 82 Sunbird, or the like might be what I'm looking for. Just seeing if anyone else has explored this.
Thanks for the read, Aaron
So, I went on RockAuto and found a Pontiac Phoenix, which is basically the Chevy Citation... it came with the Pontiac 151 / 2.5 GM engine, and they have a vacuum advance distributor:
First thing you'll notice is that the gear and shaft look different... so you have the vacuum advance one above, and then this one below which is the Pontiac Fiero one...
Let me post this first so I can look at them side by side, and then I'll edit with my comments...
Originally posted by 82-T/A [At Work]: Let me post this first so I can look at them side by side, and then I'll edit with my comments...
EDIT: Ok, one of the things I find frustrating is that GM was constantly changing the casting for the engine. Almost every 2-3 years, the engine changed entirely enough that things couldn't be swapped over. Like 86-87 are totally different engine blocks. Anyway, if I look at the two distributors, the gear is in a different location from the older style (higher up) than the newer style (further down). But we really don't know. If it gets to the point where you think you're going to have to change out the oil pump (what it connects to), then you might as well swap in a totally different motor.
I'd guess maybe you have the option of swapping over the gear (and drilling a hole in the shaft) for the older distributor so you can put the newer style cam gear on it, but then... is the distance between the mating surface and the end of the shaft the same (likely not). So I think you're going to run into issues.
I haven't looked up information on the Holley Sniper, but I'm wondering it it doesn't provide some kind of seamless connectivity here? Let me do some quick research.
[This message has been edited by 82-T/A [At Work] (edited 09-20-2024).]
It has detailed instructions with NO timing control, timing control, or using a fancy aftermarket distributor (which isn't available for the Iron Duke). Either way, the only two things that come off the distributor, which you'll use, is the magneto... that's the little coil under the rotor that has the green and white (reflected as green and black in teh diagram).
I think that's literally all you need... and connection to the TACH signal... which comes off the coil or whatever (I can't remember).
Thoughts? Anyone else?
I plan to install one on my daughter's Iron Duke... but we need to get it running first.
Regardless of the option you choose... that might be a better option since the distributor directly fits your engine (needs no modification), but STILL uses "Electronic Spark Control" which is called ESC. This was done during a time when fuel injection was not being offered on most cars, but they did offer timing advance through computer control. You could buy THAT distributor and use it with the aforementioned MSD box above, or buy a 1982 ESC box and use that just for timing: https://www.rockauto.com/en...0054&pt=2896&jsn=477
That "ECM" does nothing for fuel, other than a single sensor that sits on the carburetor (which you can ignore). But, for the most part, you can use it to control timing advance in the exact same way you do not.
Awesome information! And I thought I had covered some ground with my researching! That is what I thought I was seeing too, two different driven gear variants. I agree, MSD ignition boxes are an awesome addition to an ignition system. I would have no problem swapping gears on the distributor shaft if the diameters were the same, ...one would assume they were, BUT, may not be. Thank you for the info, I will study up on these options, and reply back with the results. One last thing, I believe the first year Chevy introduced the HEI distributor was 74, so the approximate years of the Phoenix you are suggesting are around 80 - 84? So would you think around 82?
I have 2 of these HEI monstrosities when I was running a carb on my Indy's SD4 engine. One has performance modified weights/springs/vacuum/bronze gear etc. - the other is stock.
Awesome information! And I thought I had covered some ground with my researching! That is what I thought I was seeing too, two different driven gear variants. I agree, MSD ignition boxes are an awesome addition to an ignition system. I would have no problem swapping gears on the distributor shaft if the diameters were the same, ...one would assume they were, BUT, may not be. Thank you for the info, I will study up on these options, and reply back with the results. One last thing, I believe the first year Chevy introduced the HEI distributor was 74, so the approximate years of the Phoenix you are suggesting are around 80 - 84? So would you think around 82?
Thank you for your time, and efforts! Aaron B
Let me know what you decide... I'm very curious what you end up doing, if for no other reason than I'd love the knowledge in the future (I may create a page for it on my website).
It looked to me like the later year Pontiac Phoenix was the best one to go with, but I'd ask FieroSound if maybe he's willing to sell one of those, or where he got them from. That solves your problem immediately. If you do decide to go with the later Pontiac Phoenix distributor, it will require you to use the MSD 6EFI box (which is the direction I would personally go).
For what it's worth... or FWIW as they kids say, the MSD box provides some benefit in the area of smoother idle, slightly improved fuel economy due to improved engine efficiency, and better emissions. Truth be told, because it's a lower-rpm 4 cyl, the benefit won't be as much as you might see on say, a hopped up V6/60... but it's still going to improve your around-town driving. And... it seems it already works well with the Holley Sniper (I think Holley owns MSD now).
Both Davis and Proform make stand alone HEI distrbutors with internal mechanical advance.
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