Hei vs points.

-
Iv been looking at some dwell meters already too. :rolleyes::lol: like I don't have enough to do already. Idk why but that old school stuff just intrigues me. I want to learn as much as I can about the old school methods of tuning. Carb tuning, points, timing, vacuum tuning etc!
dwell ? I think GM :D . Points in a mopar, .016-.018 and snap the cap back on.
 
dwell ? I think GM :D . Points in a mopar, .016-.018 and snap the cap back on.
I was watching a utg video, he was showing a gm distributor that is tunable on the run with a dwell meter and Allen wrench thru the side of the dist I think it was a dual points distributor
 
Www.designed2drive.com bracket. $25 shipped I think. I homemade the GM to mopar angled adaptor. Stock mopar electronic distributor I rebuilt that was from a 1974 318. Thicker advance spring removed and Mister Gasket pn# MRG915 lighter spring installed.

downloadfile-10.jpg


downloadfile-20.jpg


20150111_140121.jpeg
 
Dartfreak75,
Yep, The GM distributor had a sliding metal door, you can lift it and adjust the points dwell easily, while it ran.
They even made a flexible allen driver to get in around the air cleaner and wires...
Thats good that you are motivated.
If you can find and talk to an older or retired mechanic, like in his late 50s or 60s, you could learn alot. Sometimes these guys appreciate a motivated learner.
 
Real simple really. Stock mopar connector to stock GM connector, then use the thick shrink tube that has heat activated glue. When it shrinks and is still pliable because it's hot, bend it 90° and hold it like that till it cools off.
 
Real simple really. Stock mopar connector to stock GM connector, then use the thick shrink tube that has heat activated glue. When it shrinks and is still pliable because it's hot, bend it 90° and hold it like that till it cools off.
where did you get your gm connector?
 
A dirt track buddy gave it to me out of a junk HEI distributor on his junk pile behind his shop. The mopar connector I clipped off a van in the junkyard. The distributor he junked because the shaft slopped out and destroyed the reluctor tips. He pulled the coil, and tossed it on the scrap pile
 
The other little interesting tidbit is that if you have a Mopar breakerless system and a spare points distro, you don't even need to change anything to drop the points in.

Let's "say" the ECU goes bad. All you need do is drop in the points dist, unplug the ECU and hook the points wire to the coil neg. The resistor is hooked up the same. Not a bad idea to carry a spare resistor.

I like HEI modules. I used one on mine with no resistor, stock coil.
Or you can just carry a spare ecu in the glove box.
 
Dartfreak75,
Yep, The GM distributor had a sliding metal door, you can lift it and adjust the points dwell easily, while it ran.
They even made a flexible allen driver to get in around the air cleaner and wires...
Thats good that you are motivated.
If you can find and talk to an older or retired mechanic, like in his late 50s or 60s, you could learn alot. Sometimes these guys appreciate a motivated learner.
Yea I see it as a dying art. When I talk to guys my age or younger its all Efi, computerized timing curves, turbos, chips and tuners. Noone knows how to setup points or tune a carb anymore! At least not in my circle of car guys.
 
A dirt track buddy gave it to me out of a junk HEI distributor on his junk pile behind his shop. The mopar connector I clipped off a van in the junkyard. The distributor he junked because the shaft slopped out and destroyed the reluctor tips. He pulled the coil, and tossed it on the scrap pile

that’s where it belongs, on the junk pile.
Friends don’t let friends run chivvie parts on mopars.
 
Yea I see it as a dying art. When I talk to guys my age or younger its all Efi, computerized timing curves, turbos, chips and tuners. Noone knows how to setup points or tune a carb anymore! At least not in my circle of car guys.

Yeah, and for people our age, EFI was basically on almost every car by the time we were 2 years old. So a lot of people in that group view carbs and especially points as obsolete. Unless they are into old cars they would have no need to worry about this stuff...and of course you can convert one to EFI if you would like also.

If you understand how they work, you can do both. That's the most important part. I touched both and I know which one I would pick for my own stuff.
 
Not hei or points related, but ignition related! A very cool video on distributor tuning. This is great i really enjoyed this. Thats gonna be one smart kid!
 
Yeah, and for people our age, EFI was basically on almost every car by the time we were 2 years old. So a lot of people in that group view carbs and especially points as obsolete. Unless they are into old cars they would have no need to worry about this stuff...and of course you can convert one to EFI if you would like also.

If you understand how they work, you can do both. That's the most important part. I touched both and I know which one I would pick for my own stuff.
Yea that is a great point. Im having all sorts of electrical issues so im trying to learn all I can about it. Iv just got sucked up into the ignition part of the electrical now I can't stop lol
 
The old tried and true point ignition was intriguing.
My grand father used to set points gap with a cardboard match stick, after he lit up his L&M cigarette, of course.
I kinda miss those days.
Life was simple.
 
Last edited:
I understand the advantages of EFI and Electronic ignition.
Do they even touch on carbs and points in trade schools anymore?
 
I understand the advantages of EFI and Electronic ignition.
Do they even touch on carbs and points in trade schools anymore?
No I doubt it. Im not sure if they even have a trade school in my area anymore. We had a trade school when I was in high school it was for 11th and 12th grade only tho and I never made it that far. Lol yea I was a dumbass! It wasn't cause I wasn't smart enough it was because I was to stubborn and rebellious to apply myself. I'd rather go to work and learn for myself. I started working full-time at 16 and was on my own at 17. My parents didn't approve of my new found independence. Lol
 
With POINTS you can be sure of five things:
- the rubbing block will wear.....
- the ign timing will then retard....
- costing power & fuel economy....
- if the engine is a high[er] rpm engine, points may bounce causing erratic timing & power loss...
- points contact surface erosion causes cyl-to-cyl timing variations.

None of the above defects happens with elec ign.

A word of caution using the GM 4 pin module with a high rpm engine. GM used adaptive dwell. At low rpms dwell is reduced electronically because there is more time to charge the coil; this reduces coil heating, which reduces power loss in the coil. My understanding is GM uses a feedback cct using the p/up coil as part of the f/b cct to control dwell time. The Mopar p/up is a lot lower resistance, usually 150-300 ohms, where the GM pick up is much higher, about 700-1200 ohms. This [ ign coil saturation ] may be an issue at higher rpms, more at: www.worldphaco.net
Another benefit of elec jgn is spark plug gap; probably limited to 0.030" with points. GM HEI used gaps of 0.060 & 0.080"; Ford elec ign used 0.060" gaps.
 
With POINTS you can be sure of five things:
- the rubbing block will wear.....
- the ign timing will then retard....
- costing power & fuel economy....
- if the engine is a high[er] rpm engine, points may bounce causing erratic timing & power loss...
- points contact surface erosion causes cyl-to-cyl timing variations.

None of the above defects happens with elec ign.

A word of caution using the GM 4 pin module with a high rpm engine. GM used adaptive dwell. At low rpms dwell is reduced electronically because there is more time to charge the coil; this reduces coil heating, which reduces power loss in the coil. My understanding is GM uses a feedback cct using the p/up coil as part of the f/b cct to control dwell time. The Mopar p/up is a lot lower resistance, usually 150-300 ohms, where the GM pick up is much higher, about 700-1200 ohms. This [ ign coil saturation ] may be an issue at higher rpms, more at: www.worldphaco.net
Another benefit of elec jgn is spark plug gap; probably limited to 0.030" with points. GM HEI used gaps of 0.060 & 0.080"; Ford elec ign used 0.060" gaps.

I will also add to that statement. Points are hobbled with a 6V ballast resistor to prevent arcing and burning of the surfaces of the points. The whole purpose of a dual point system was I believe a secondary spark to help burn the rest of the fuel. Was it better than single point setups? Ya sure. It worked. Muscle cars in the 60s came standard with dual points. It was the "hot setup" for it's time. But time moves on. We all know electronic ignitions are more accurate than points and for the most part are a set it and forget it kinda thing.

However GMs HEI unlike Chryslers electronic system ditched the 6V resistor (GM used a resistor wire with points) and ran a straight 12V. This opened up possibilities for a way hotter spark, wider plug gap and more complete combustion. Chrysler kept a ballast resistor and 6V. Yes It was superior to points, but if comparing stock systems it was just not as good as the HEI system in regards to spark strength.

I know theres some people that Phoo phoo using non mopar parts on a Chrysler product and that's your opinion. Your entitled to it, but to be honest when comparing the 2 "stock systems", the HEI just comes out on top. That being said, I would never run one of those fat cap DUI HEI distributors in a mopar. They fit like **** and dont look right. I prefer something more hidden that still gets the job done. The 4 pin modules were designed to be in a hot environment. After all they were inside the fat cap distributors since about 1973.
 
Last edited:
And they don’t retard with RPM.
And this IS something. I have a factory Chrysler distributor with the slots welded (locked) in a 318 just because it happens to be what I have. I have the timing set at 30* BTDC, but when the RPM's get up there (4500 ? ), it backs itself down to about 26*.
 
Well THAT IS NOT true either. Mopar single point dist. are some of the worst OEM design I've seen. GM generally was some of the best. I used to buy the little bushing kits you could buy "back then" for Mopar single point dist.s 3 or 4 at a time. Shaft play, spark scatter, change in dwell with vacuum advance, those are NOT an HP design.

Generally the tang drive is not a really good plan. There's been all sorts of bushing/ spring loaded/ thrust add-on nonsense over the years to try and reduce spark scatter on Mopar dist's both SB and B/RB
 
Well THAT IS NOT true either. Mopar single point dist. are some of the worst OEM design I've seen. GM generally was some of the best. I used to buy the little bushing kits you could buy "back then" for Mopar single point dist.s 3 or 4 at a time. Shaft play, spark scatter, change in dwell with vacuum advance, those are NOT an HP design.

Generally the tang drive is not a really good plan. There's been all sorts of bushing/ spring loaded/ thrust add-on nonsense over the years to try and reduce spark scatter on Mopar dist's both SB and B/RB


That’s from the timing chain. I have never found the GM style of advance to be worth much. And the gear on the distributor wears out the bushings in the distributor very quickly.

There’s lots of things to not like about any OE part. GM was far from decent on most things, they just have the aftermarket cornered. That’s where the R&D comes from, not out of GM.
 
-
Back
Top