1946 BN IHC
Member
??? Is it possible, wise, economic, and practable to re work the distributer that has no points, electronic I think, and install points? Would the outfit gain better fuel milage or not?
- Thread starter 1946 BN IHC
- Start date
Steve@Advance
Well-known Member
No, that would be a big step backward. Especially with the quality of today's ignition parts.
I believe that would have been the HEI series of distributors. They were good for their day, a huge improvement over points.
Some of the downfalls were:
The rotor burning through the center (usually aggravated by running bad wires or worn plugs).
Primary leads breaking off the module.
Centrifugal advance wearing out, springs rusting and breaking, freezing in position. (if equipped)
Vacuum advance failing. (if equipped)
Coil arcing to ground internally (again, bad wires and worn plugs).
But all and all, they were great distributors for their time.
I believe that would have been the HEI series of distributors. They were good for their day, a huge improvement over points.
Some of the downfalls were:
The rotor burning through the center (usually aggravated by running bad wires or worn plugs).
Primary leads breaking off the module.
Centrifugal advance wearing out, springs rusting and breaking, freezing in position. (if equipped)
Vacuum advance failing. (if equipped)
Coil arcing to ground internally (again, bad wires and worn plugs).
But all and all, they were great distributors for their time.
timcasbolt
Well-known Member
There are still HEI's out there on the road doing their job after 45 years. They are very reliable. New ones are still available, and the aftermarket produces high performance versions that appear in race cars. I wouldn't switch back to points, but if you do, a steel resistance wire or ballast resistor would be needed to reduce the voltage going to the points.
timcasbolt
Well-known Member
Forgot to answer the other part of your question: No, you can't retrofit points to an HEI distributor. (At least not without some mad machining skills)
MarkB_MI
Well-known Member
- Location
- Motown USA
The obvious question is "why?"
It was considered a huge leap forward when GM introduced HEI. Lots of folks convert from points to HEI; I've never heard of anyone going the other way. Basically you would have to remove the distributor and disconnect the ECM, then you could put in an old-style distributor and coil, maybe even a Mallory dual-point setup. But you would be disabling the knock sensors and other features that control the ignition advance and replacing them with the archaic mechanical/vacuum advance of the pre-HEI setup. Not to mention replacing the powerful HEI spark with a much weaker one. It's a fairly safe bet you would see poorer mileage with the old-school setup.
It was considered a huge leap forward when GM introduced HEI. Lots of folks convert from points to HEI; I've never heard of anyone going the other way. Basically you would have to remove the distributor and disconnect the ECM, then you could put in an old-style distributor and coil, maybe even a Mallory dual-point setup. But you would be disabling the knock sensors and other features that control the ignition advance and replacing them with the archaic mechanical/vacuum advance of the pre-HEI setup. Not to mention replacing the powerful HEI spark with a much weaker one. It's a fairly safe bet you would see poorer mileage with the old-school setup.
1946 BN IHC
Member
Thank you Mark and Steve.i will check for each of the wires that were mentioned since this unit has sat for a while. I know I need to check the workings of the chock since the chock no light doesn't go completly out even when fully warmed up. So at the same time I wil replace plugs and chech plug wires and otherwires leading to and from distributer and coil.
May you each have a pleasent Christmas
Wm.
May you each have a pleasent Christmas
Wm.
It would probably be easier to install a complete distributor that has points than to rework the HEI distributor. GM started using HEI ignition in the mid-1970's. You would need to find a 40 plus year old distributor that matches your application and is still in usable condition. What is wrong with your HEI?
PaGlenn
Well-known Member
- Location
- New Milford Penna
I purchased a high performance HEI aluminum billet distributor a few years back for 45.00 free shipping on Ebay. Up to now it still works fine.
MarkB_MI
Well-known Member
- Location
- Motown USA
> Would an 83 have advance in distributor, or computer?
I'm not sure. According to <a href="https://en.wikipedia.org/wiki/High_energy_ignition">this article</a>, knock sensors were introduced in '78. But it doesn't say when GM went to true computerized engine control. Should be easy enough for the original poster to figure out; the non-ECM distributor should have a vacuum advance.
I'm not sure. According to <a href="https://en.wikipedia.org/wiki/High_energy_ignition">this article</a>, knock sensors were introduced in '78. But it doesn't say when GM went to true computerized engine control. Should be easy enough for the original poster to figure out; the non-ECM distributor should have a vacuum advance.
dr sportster
Well-known Member
Just buy a Mallory Uni-lite distributor. Electric eye style. On the money.
"Should be easy enough for the original poster to figure out; the non-ECM distributor should have a vacuum advance."
NOT quite so clear-cut! In that era (ealy 80's), GM had "ESC" (electronic spark control) that could RETARD timing if it "heard" knocking, but the distributors still had vacuum AND mechanical ADVANCE.
With the truck V-8's, Chevy phased in fuel injection (and fully computerized timing control) about 1987.
There were several module versions, simple HEI, ESC, full ECM timing control, etc. with a variety of "pin counts" to make it all work.
MarkB_MI
Well-known Member
- Location
- Motown USA
> NOT quite so clear-cut! In that era (ealy 80's), GM had "ESC" (electronic spark control) that could RETARD timing if it "heard" knocking, but the distributors still had vacuum AND mechanical ADVANCE.
Yes, but shouldn't the presence of a vacuum dashpot betray that a particular distributor has vacuum (and presumably mechanical) advance?
Yes, but shouldn't the presence of a vacuum dashpot betray that a particular distributor has vacuum (and presumably mechanical) advance?
Keith Molden
Well-known Member
I really don't think you would see much if any change in fuel mileage. If it quit running, you might want to replace the rotor cap. They had a habit of burning a very small hole in them and shorting out. Take it off and see if there is a little black spot on the underside. If it does, replace it and you're good for a lot of miles. When we had the garage and wrecker service back in the 80s, we had an extra chevy rotor in every wrecker. We replaced a lot of them and got the owner back on the road quick. Just my thoughts, Keith
Destroked 450
Well-known Member
- Location
- Harned, Ky
I'd replace it with a HEI distributor out of a late 70's 350 engine.
GM was playing around with computer control from around 81 or 82 until they came out with throttle body fuel injection.
The carbs and distributors where junk during that time.
My '84 GMC with a 305/(5 liter for you metric guys)it had what GM called TCS Transmission Controlled Spark. they gave trouble. Mine did when it was about 20 years old. There was a buletin on it and the fix was to jumper two of the wires in the 4 pin plug to basically bypass the computer as far as spark was concerned. I did it and it worked much better after that.
I am aware of nothing on the engine that detected knock. You set the timing with a timing light.
I put an HEI distribuitor from a wrecked 78 Monte Carlo in my '69 GMC 1 ton and it works very well. That was 1993-ish. It has been relatively trouble free except that this year it finally decided it needed another set of spark plug wires.
I would replace the HEI today rather than go back to points if I had to.
I am aware of nothing on the engine that detected knock. You set the timing with a timing light.
I put an HEI distribuitor from a wrecked 78 Monte Carlo in my '69 GMC 1 ton and it works very well. That was 1993-ish. It has been relatively trouble free except that this year it finally decided it needed another set of spark plug wires.
I would replace the HEI today rather than go back to points if I had to.
Hobo,NC
Well-known Member
- Location
- Sanford, NC
How can anyone in their right mind convert a GM HEI back to points...
onefarmer
Well-known Member
- Location
- 6735 S Lowell Rd, St Johns, Mi 48879
Why?? I put a HEI in my 66 C60. Never ran better.
Reworking a dist to install points is not too good an idea. Points are good for the yearly tune up and tweaking to maintain the 30 degree dwell angle. If you stay on top of the dwell angle, the points should last a bit longer. Electronic requires no adjustment.
If you put the points back in it, you will need either a resistor wire or a ballast resistor in the system somewhere to get the voltage down. HEI runs 14V wire right up to the dist.
As your putting points back in, the dwell angle will effect timing. Timing will effect mileage and performance.
If you stay on top of the dwell angle, you should not see a difference in mileage, If you don't look at it on a regular basis, your mileage will suffer.
If you put the points back in it, you will need either a resistor wire or a ballast resistor in the system somewhere to get the voltage down. HEI runs 14V wire right up to the dist.
As your putting points back in, the dwell angle will effect timing. Timing will effect mileage and performance.
If you stay on top of the dwell angle, you should not see a difference in mileage, If you don't look at it on a regular basis, your mileage will suffer.
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