need help with points

livin_lower

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Sep 14, 2009
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I am in the process of installing a accell points style deistibutor with MSD Blaster coil on my 79, the car had a HEI type distributor, I know that it sounds like I am taking a step backwards but the HEI style distributor doesnt clear my tunnel ram. does anyone have a wiring diagram for this style distributor I am a little lost on where to start.:sos:
 
No, I think you are right. I hear the term "small cap HEI" used in reference to the distributor used in TPI applications. Forgot that the early HEI is a completely different animal.

What does the term EST mean?
 
They made them for 6 cyl and 4 cyl with the coil mounted on the ebgine side. Don't remember the models or years, but they were non computer.

69427
Perhaps you can answer this.
Can you not use points to trigger the hei module.

I know the module can be mounted almost anywhere with a heat sink. I know dist have been converted to hei for almost any application including forklifts, Jeep engines etc.
 
No, I think you are right. I hear the term "small cap HEI" used in reference to the distributor used in TPI applications. Forgot that the early HEI is a completely different animal.

What does the term EST mean?

Electronic Spark Timing. That's the "official" designation for the distributor that uses the seven terminal module and ECM.
 
I found a small mallory distributor that has been converted to HEI but I have to run and external coil, so I bought a MSD blaster 2, how do I wire the coil up since I use to have HEI with and internal coil.
 
They made them for 6 cyl and 4 cyl with the coil mounted on the ebgine side. Don't remember the models or years, but they were non computer. That could be useful for some mix and match conversion projects. If you happen upon some of these, let us know what vehicles they were used on.

69427
Perhaps you can answer this.
Can you not use points to trigger the hei module. Wow, without looking at an old schematic, I couldn't say for sure. The HEI module is designed to operate from a quasi-sinewave pickup signal (the module needs a slight negative voltage to shut off the current accurately). If you did some kind of capacitively coupled signal from the points, you could probably fake it. The module also uses the pickup signal waveform to set thresholds for the variable dwell time/angle circuit. The dwelltime obviously wouldn't be very accurate with a "squarewave" type input trigger.
It's probably possible, but I wouldn't recommend it.


I know the module can be mounted almost anywhere with a heat sink. I know dist have been converted to hei for almost any application including forklifts, Jeep engines etc.

I converted my original '69 distributor to use an HEI module back around 1984. Great plug life, and smooth operation at high loads and RPMs. The module is mounted to a small heat sink under the shielding.
 
I converted my original '69 distributor to use an HEI module back around 1984. Great plug life, and smooth operation at high loads and RPMs. The module is mounted to a small heat sink under the shielding.

I think we would all like to see some kind of pictures/write up of that if you have the time.
 
I converted my original '69 distributor to use an HEI module back around 1984. Great plug life, and smooth operation at high loads and RPMs. The module is mounted to a small heat sink under the shielding.

I think we would all like to see some kind of pictures/write up of that if you have the time.

Yeh, Mike curious about that myself, what coil did you use, use a series resistor?? and why did you do that?? not easier to use a HEI??
 
I converted my original '69 distributor to use an HEI module back around 1984. Great plug life, and smooth operation at high loads and RPMs. The module is mounted to a small heat sink under the shielding.

I think we would all like to see some kind of pictures/write up of that if you have the time.

Yeh, Mike curious about that myself, what coil did you use, use a series resistor?? and why did you do that?? not easier to use a HEI??

Probably to save the mech tach function/appearence.
 
I converted my original '69 distributor to use an HEI module back around 1984. Great plug life, and smooth operation at high loads and RPMs. The module is mounted to a small heat sink under the shielding.

I think we would all like to see some kind of pictures/write up of that if you have the time.

Yeh, Mike curious about that myself, what coil did you use, use a series resistor?? and why did you do that?? not easier to use a HEI??

Probably to save the mech tach function/appearence.

DING. DING. DING. DING. We have a winner!

(Okay, it was also cheaper. But ease of conversion was a big factor. I'll try to dig up some pictures, and do a short writeup description.)
 
I converted my original '69 distributor to use an HEI module back around 1984. Great plug life, and smooth operation at high loads and RPMs. The module is mounted to a small heat sink under the shielding.

I think we would all like to see some kind of pictures/write up of that if you have the time.

Yeh, Mike curious about that myself, what coil did you use, use a series resistor?? and why did you do that?? not easier to use a HEI??

Probably to save the mech tach function/appearence.

DING. DING. DING. DING. We have a winner!

(Okay, it was also cheaper. But ease of conversion was a big factor. I'll try to dig up some pictures, and do a short writeup description.)

OH, duhhh...ok, of course....I went electronic '75-77? tach so long ago I forget about them mechanical things...

they never made a accurate speedo, I found out recently, hate to guess about a tach, which even the electronic is off some 5% at higher RPM's....
 
I converted my original '69 distributor to use an HEI module back around 1984. Great plug life, and smooth operation at high loads and RPMs. The module is mounted to a small heat sink under the shielding.

I think we would all like to see some kind of pictures/write up of that if you have the time.

Well, I've struck out trying to find some pictures on the web of the parts I'm using in my distributor, and I'm just too lazy to pull the shielding and cap/rotor off the distributor, so I'll try to describe what I have, and then take some pictures down the road when I put the new engine in.
Some history. In 1974 I bought an electronic ignition conversion kit (Stinger Ignition, IIRC), made by Hayes. The kit included an extruded, 8 pin reluctor wheel that pressed over the distributor points cam, a pickup coil (resembling some of the old Chrysler type pickup coils), and a potted up PCB control box.
The system worked fine for a half dozen years (and most of that was vehicle storage time while I was in college), and then I started to notice drivability/misfire issues under load and higher (> 3500) RPM. I pulled the whole system out of the car, and brought it into work one day to measure what was going on. The waveform out of the distributor looked steady and predictable over RPM. The output of the box, however, was erratic at times. A component on the PCB (printed circuit board) was apparently breaking down. As the control box was all potted up, there was no way of probing inside to see where the faulty component was. That was the start of my distrust of underhood ignition systems that used PCBs.
So, what to do? I wasn't thrilled about shelling out the money to buy another control box, but I didn't want the car sitting in the garage unable to run, either. I did notice while testing the distributor that the pickup coil signal looked essentially identical to what an HEI distributor pickup coil puts out. So, what about using an HEI module instead? They're cheap, available, and stone reliable. I hooked up a four terminal HEI module to the distributor and coil on the lab bench, and shazam, it ran like a champ!
I went home and reinstalled the distributor, and with a small custom wiring harness, I installed the module and mini heatsink inside the chrome ignition shielding. As the HEI module automatically controls the primary current level and dwell time, I disconnected the stock ballast resistance wire and ran a new wire to the fuse box. (In hindsight, I could have left the ballast wire still hooked up, as it wouldn't affect the operation of the ignition.)
The car fired right up. I drove it around, and no more misfire at higher loads and RPMs.
Now, the dry engineering stuff: The stock coil specs were roughly 1.9 ohms, and perhaps 8 mH inductance on the primary windings. A stock HEI coil has about half an ohm (.5) resistance, and about 6-8 mH of inductance. This means that the HEI coil will charge very fast (not requiring much dwell time/angle), while the stock coil, due to its higher resistance and inductance, would require longer dwell times. Looking at the dwell signal with a 'scope showed that the laws of physics were still in effect on my engine. The oilcan coil required more dwell time/angle to charge up to what the HEI module was trying to attain. The HEI module is calibrated to modify the dwell under all conditions to try to draw 5.6-5.8 amps in the primary windings. This is easy to do with a low resistance, lower inductance coil, but more difficult with a higher resistance and inductance coil. The module "compensates" in this case by increasing the dwell time/angle to allow more time for the primary current to charge the coil. So, the net result is, I have additional primary current (and energy, versus the original points setup) over the complete RPM range due to the variable dwell circuit increasing the dwell at higher RPMs (40 degrees at higher speeds).
"Optimizing" the circuit would entail changing the coil to a lower resistance, lower inductance unit to allow the current to ramp up faster. I've got a variety of "pre-driven" coils gathering dust on the shelf waiting for a opportunity when I can devote time to doing some actual electrical measurements on the engine, and determine which coil I want to swap in to replace the original coil.
Given that both engines I've had in this car have run smoothly with this setup all these years, I haven't had any feelings of urgency on this, and I've just spent my free time trying to update the chassis, instead.
Well, I'm getting a blister on my typing finger, so I'll stop for now, Please feel free to ask any followup questions.
 
I am in the process of installing a accell points style deistibutor with MSD Blaster coil on my 79, the car had a HEI type distributor, I know that it sounds like I am taking a step backwards but the HEI style distributor doesnt clear my tunnel ram. does anyone have a wiring diagram for this style distributor I am a little lost on where to start.:sos:

In answer to your original question, a points distributor provides the gounding path for the primary side of the coil through the points. Therefore, the "+" power from your ignition key goes to the "+" side of the coil. The "-" side of the coil is hooked up to the primary lead wire on the distributor, which goes directly to the points. A standard points distributor only has that one primary wire. Keep in mind that you cannot hook up the big red ignition wire on your HEI car to the "+" side of the coil - you have to use a ballast resistor in that wire if your points-style system is to survive. You should also run a wire from your starter's "R" terminal to the "+" side of the coil so you get a full 12 volts at cranking.

A points distributor with a good set of points and a good coil will perform very well. Make sure it has a quick advance curve in it - most aftermarket distributors are set up with a very lazy curve.

Lars
 
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