Pertronix Ignitor Install In 1973 911

[dlague]

I just put a Pertronix Ignitor in my 1973 911. I really like the results, and I have to say I learned an aweful lot about the ignition and what makes it all work. Also learned lots about what to do and what not to do when considering this installation.

This site was very helpful in some ways and yet I was surprised that there was not more information on doing this great upgrade. Many people left with points in their early Porsche cars would be well advised to do this conversion.

I could do a step by step with some photos, but I don't know what the level of interest may be in this conversion. With this in mind I will just start with the big things I learned and pass those along to start.

I have a 1973 911 with a 2.7 engine in it. I have been pretty good about keeping the dwell and timing right. However it is annoying to know that you will have to get at those points at least once a year. When the dwell goes off the timing goes off and I even got stranded once when the dwell essentially went away and of course the car stopped running!

I had 3 major hurdles when doing this conversion. Thry were:

1. Getting the RIGHT Pertronix kit
2. Getting information on Bosch CDI compatibility and wiring.
3. Distributor cap interference with the Pertronix module.


#1. My distributor is a 1973.5 unit or one with 168 001 for the last of the part number. Frist time I got the 1973 unit and the points pivot and adjusting screw are mirror image. Pelican parts was great at taking my old unit back and getting me the right one. If you don't know the part number on your distributor, check it.

the part number is on the BACK of the distributor, so you may need to take it out. Follow the directions on this forum for removing the distributor. What you need to do is get Cyl #1 up on TDC and this means the rotor will line up with the mark on the distributor body and the TDC mark on the lower pulley.

#2. this part was interesting. If you did around the Pertronix site you will find a wiring diagram for the Bosch CDI. What you need to know is that the black wire coming out of the Pertronix goes to the black wire that is normally plugged into the spade connector on the distributor. This is the black wire going back to the CDI box with the "points" [now Pertronix Ignitor] signal. I used the exiting black wire, and I shortened the Pertronix black wire to 6" and crimped on a male spade lug so this wire can connect to the wire going back to the CDI.

The instructions that come in the Ignitor I or II box tells you how to hook up to a conventional coil, NOT a CDI setup. DON'T HOOK THE BLACK WIRE TO THE COIL if you have CDI in your Porsche.

The other wire on the Pertronix, the red one needs to have switched 12 volts hooked to it. I ran a wire back to the CDI box +12VDC red wire. This turns on the Pertonix module at the same time the the CDI is turned on.

The sales information on the Pertronix Ignitor is not really cut and dried that it will work with CDI. It works very well with CDI, but you have to really dig to get hints that it does.
#3 was interesting. I installed a black bodied Pertronix Ignitor I module in the car following the instructions with the above wiring setup. It started well and I set the timing. It ran well.

I took the car our for some testing and breaking in and when warmed up it would hang up at 2000 RPM and would return eventually to 1000 RPM. What I found was that the Pertronix epoxied module was hitting the distributor cap, and it was interfering with the movement of the vacuum advance. I sanded a bit of epoxy off and reinstalled it and it was a lot better. The base plate that the Pertronix mounts to rotates with the application of engine vacuum to the distributor. My theory is that the Pertronix unit was binding on the distributor cap when the engine got hot. You can't see this with the cap on, but once when the idle was "hung up", I wiggled the cap slightly and the idle dropped immediately.

You can put a piece of tubing on the advance diaphragm fitting and suck on it and the plate should move.

I decided to install a Pertonix Ignitor II next. This model has the ability to turn off automatically when the key is left on with the engine not running. Pertronix also says it will vary the Dwell to conditions and RPM. This module is red, and actually is a little smaller and thinner than the black Ignitor I. I also used some 60 grit emory paper on a flat surface to knock the edge off the module to be sure it did not hit the cap.

After setting the unit up according to the instructions and installing it, I was very impressed. I had to readjust the timing but that was expected. The idle was more stable and it seemed to rev more smoothly and solidly.

This is a great upgrade.

I can fill in more details if there is some interest.

Dick

[trekkor]

I just put a Pertronix unit in my '74.
Fired right off.

Points and condensor are not what I will run.


KT

[Augustus]

I would like to see the step by step process with pictures.
It would be very helpful.
Thanks!

[dlague]

I will work on a step by step. I need to get more photos so that I can point out some of the key points.

With the right kit from Pertronix, the installation is much like installing points. They even supply a feeler gauge to set the air gap between the new magnetic rotor and the hall effect pickup.

The wiring is the key. It is not difficult, but the enclosed directions talk about a coil and points ignition and not one with CDI. If you Porsche has CDI you need to send the signal from the Pertonix to the CDI box. This is logical and easy, you just don't want to hook it to the coil as the instructions say.

I will work on it this week...have a busy week coming up but will find time.

Performance without points is really terrfic. Idle is very stable and smoothe. Mid-range power feels great and it seems to be much better on the upper end. When you think about how those points must bounce around at 5000 to 7000 rpm, I am sure the Pertonix is much better.

Remember I drove this 911 close to 100,000 with the points, so I am quite familiar with how they felt and worked. AND I don't have to adjust them any more!!

[tmctguer]

here's my post w/ photos on the same project:

Pertronix Installation in '73 911E -- complete with photos

some of my photo's were a bit out of focus but I think they got the key points across.

how did you make your electrical connections? i am curious how others solved that problem.

[dlague]

Hey Rick,

Your post was very helpful to me. Thank you for posting it.

It was the first time I saw that Pertonix wiring diagram that confirmed my thoughts about how to hook it up with CDI.

Once I had that figured out, the install was easier. I did not run wires all the way back to the CDI. The black wire at the distributor goes there already and carried the signal from the points. I shortened the black wire out of the Pertronix to 6 inches, and crimped on a flat male spade connector there and plugged in the wire that normally connects to the distributor with points. this is the black wire that goes back to the CDI.

The red wire on the Pertronix Ignitor needs switched +12 VDC. I kept that wire the original length, and crimped a round connector to it. I took a piece of silicone [this is the same type of wire that Pertronix uses - more heat resistance] red wire and ran it to the connector that supplies switched + 12 VDC to the CDI box. I stripped the insulation back and soldered this new wire just ahead of the spade connector to the CDI red wiring harness. I like soldered connections. I have only one take apart connector in each wire.

I zip tied the red wire to the harness going back to the CDI area.

In summary I only added 1 red wire from the Pertronix back to the CDI area. And I hooked this up downstream from where you did yours.

I wanted to use as few connectors as I could and did not want any double spade connectors that could fail in the system.

Ironically I had the 14 pin connector next to the CDI give me problem after the install. 34 year old connection picked up some dirt and corrosion!! Luckily I only wasted an hour finding it!!

Dick Lague

[Peter at Pelican Parts]

Added a link to this on PelicanWiki. Thanks, guys!

[orange911]

I will add a couple of comments to my recent experience on this installation on my 72 T. The Dizzy is a 169 model.

First off, I could not get the magnet seated on the cam all the way at first and the rotor would not go all the way down. I sanded down the magnet a 1/16 inch (opposite side of the magnet) and then it would go on easily, cant explain. Now I think that there is enough room that you should not have to sand. Maybe it just had a burr on the inside.

Routing of the wiring must go around the dizzy (as opposed to behind the module) so that the wires do not prevent the vacuum advance from working fully. I was trying to make use of the open screw hole just behind the module.

That leaves the only way to exit the dizzy is through the same location the existing points wire enters. To remove the grommet that secures the wire, you must remove the dizzy to unscrew the holding bracket. Not a problem, but I would have preferred to not mess with it.

Making the connections:
For the black wire I used the same spade terminal that was removed from the dizzy that connects to the CDI box and the tach. This is a a 3 way "piggy back" spade terminal that was removed from the dizzy to allow the module wires to exit.

For the red wire, I really did not want to alter the plug or cut into the red wire going to the CDI. I traced the red wire from the CDI plug and found another red wire that connected to a spade terminal. This would make a great connection if I could verify the two red wires were indeed connected. With a ohm meter I verified that there was continuity between the 2 wires. So I added a piggy back spade connector and plugged all three wires (2 wires already there and the new red wire from pertronix) to it and wrapped with electrical tape.

Cons of this installation:
1) pertronix does not give accurate directions as noted above.
2) pertronix needs to add about 18 inches of wire on the red one so that it will make contact with the proper source, not the coil. This required another unnecessary connector
3) I almost made the horrible mistake of attaching the red wire to the unswitched terminal on the rear fuse panel. Thank you volt meter. There is a switched terminal on the lower fuse, but as noted earlier, I was able to find the more correct source near the CDI plug.

Pros:
1) Car runs super smooth.
2) If I needed to do another car, I could do it in 15 minutes without the head scratching I did on this one.
3) If I ever need to go back to points, everything is reversible without evidence of change
4) No more dwell adjustments
5) Now I have a perfectly good set of points I can keep in the trunk as a back-up.

[Mukilteo911]

I love the pertronix! Oh my god, i wish i would have done this upgrade sooner, totally rocks on a carb car.

[JerryL]

Thanks for pulling this back up. As soon as i get my CDI box(s) back from Systems Consulting and get one hooked back up and working I am going to put in a pertronics II I picked up from Mike Burns about 2 yrs ago.
CDI died could not get it going got fed up and switched to kettering ignition using a blue coil, works good but know I am / was leaving something on the table.
Was going to do a MSD swap but recently re-thought that as good as the stock CDI is so sent 2 boxes off for repair (nice to have a spare) and should have plenty of spark and no tach adapter or additional wiring.

On completion of that will put in the pertronix unit.
Funny once you work around a problem and have the car running how long you put things on the shelf.

Regards

Edit: car is a 71

[dicklague]

Thanks for reviving this thread. As the original poster maybe I should post an update.

3 years later almost to the day the Pertronix is still working really well. I don't even think about dwell of point adjustments any more.

ANYONE WITH POINTS NEEDS TO INSTALL this product.

[haasad]

Can I use a single pertonix unit to trigger two cdi boxes in my homebrew twin plug ignition set up ?

My skills are of a decidedly mechanical bias so apologies if this is a stupid question ?

andy

[tobluforu]

Originally Posted by dicklague

Thanks for reviving this thread. As the original poster maybe I should post an update.

3 years later almost to the day the Pertronix is still working really well. I don't even think about dwell of point adjustments any more.

ANYONE WITH POINTS NEEDS TO INSTALL this product.

39 years and my org. cdi with points is still working.

[kodioneill]

Originally Posted by tobluforu

39 years and my org. cdi with points is still working.

I agree, I think after installing two of these units (they both failed) that they are junk. Points and CDI work great.

[JerryL]

I have the Pertronics, in 4 other cars, one did fail in the 66 912 several years ago BUT I do keep points and the small bits to go back to points in a sandwich bag in the glove boxs, easy if they fail BUT have over 20 years on some of the units.
I will also keep the little jumper I made for the cdi harness, points and a traditional coil in the 911 in case the cdi box dies again with out a spare box with me.
The most abused Pertronics unit is in my wifes MGB, distributor is right under the heater control valve, would drip on ocasion and kill the points, that unit has been in the car since the late 80's without a hicup.
As with all things run what you are comfortable with and be prepared.

Regards