'77 pertronix installation questions

[gli_ryan]

I've got this pertronix ignitor 2 for my 77 911s so I can replace the points. I've also got the matching flame thrower coil. I tried wiring this in using the instructions provided, didn't work. Dug around some on the internet, figured out the car is a cdi system, changed my wiring and still don't have a running car. Currently I'm waiting for a second set of hands to see if I have any spark. Is the cdi box going to burn up if I wired the new coil and ignitor up incorrectly for this system? Its doesn't seem to be making any noise with the key on, but I don't remember it ever making noise.

I have a white/red/white color combo for the cdi wiring. Close white has no power, middle red has 12v, far white has 5 or 6 volts. I'm not getting power at the coil, should I be? Looking around it sounds like I won't have power going to it, not until the cdi box triggers it.

I'm tired of messing around without getting any where. Any help? Can I wire out the cdi box and run just the new coil and ignitor 2?

[Topgun63]

I have the same issue with my 77....was afraid to burn up CDI, so I put points back in...answer anyone??

[Al S]

Try this..

[kodioneill]

Lot of guy's here like them and don't have any problems. I had nothing but problems with a couple units that caused surging and miss issues. A couple of my buddies with muscle cars tried them and took the units right off.

[kach22i]

Some useful information in this old thread:
Pertronix install - big backfire - 1977 2.7L

Note: Some people file a small amount of height off the bottom of the rev limiting rotor as it may sit too high with the new parts under the cap.

I don't know if you fried anything with the wrong wiring setup. A little prayer may be in order.

[Hil911]

I put a set with a Flamethrower 2 into my '76. I unplugged the CDI completely - there's no need to have it in there, so it was quite safe.

I supplied power to the system from the rear fuse box. Note that it must be a switched power - you mustn't leave the Pertronix powered up when the engine isn't running.

It ran OK but my tach went wild. Apparently that is normal and you need to buy a little box to put that right. I bought a Tach-Adapt from Bob Ashlock. A nice little device.

However, I found that the spark was not very strong. I could see occasional misses and I couldn't get rid of them by playing around with the Pertronix clearance etc. I could see the misses with my timing gun. It's possible that my power supply wasn't the best but it tested OK.

So - because it turned out that a lot of my original problem was due to poor connections because the new lead set doesn't really fit - I went back to CDI and the Pertronix is sitting with all its parts in a sandwich bag in the garage.

A couple of additions. Be a little careful with the wires in the fuse box - two are live but one is switched and one isn't. I had no rotor problems. Just make sure that the Pertronix magnet ring is pushed down properly.

[dicklague]

Pertonix wiring is quite simple. You are only adding a switched 12 vdc lead to the red wire to power the module.

The other wire is the same as the points in the old system. This wire goes to the points input on the CDI.....That is all there is to it.

I have ad pertronix in my 1973 911 for 8 years and have not touched them and had no trouble. I am running an aftermarket CDI now, and use Pertronix with the Bosch CDI with no trouble.

[gli_ryan]

I got it to fire up, then I couldn't get it again. Seemed the magnet ring wasn't sitting properly, tried pushing it down so the rotor would stop hitting the cap and broke it. Put the points back on and fired it up, returned the pertonix. Thing sucked. I'll run the points and cdi. I've got a hanging idle now though. So need to get that to go away. Ideas before I start the search and track that issue down? Timing is set, vacuum advance isn't leaking. not sure.

[Hil911]

Gosh - I didn't have any problems like that. It all went together fine.

Points are OK - if you keep an eye on them, they are reliable. I've NEVER had a car stop due to points. What did a 917 run?

How was the idling before you did the ignition? If it was fine before, then it pretty much has to be a timing issue.

Generally faster idling = more advanced. Are you at 5 BTDC with vacuum?

[gli_ryan]

I'll go over the timing again. The idle will drop to the typical 900ish, but it likes to hang up considerably higher for 5 or more seconds. What should I be shooting for as far as timing is concerned?

[kodioneill]

Check the adjustment on the valve that's attached to the back of the throttle housing. Not sure what it's called but there's a vacuum line attached to the top of it.Loosen the gland nut and turn the threaded rod/tube in about two turns. It's called vacuum limiter #15 in the parts catalog.

[bob deluke]

Take out the pertronix and put in factory points. Leave well enough alone. The only function of the points is to trigger a signal to the CD box. Have had the points in my 77 for 5 years, no problem. In the spring, I check the gap, rotor and cap, fire her up and good to go. I even have the original perma tune installed, and have had no problems with the ignition circuit ever..

[kodioneill]

Originally Posted by bob deluke

Take out the pertronix and put in factory points. Leave well enough alone. The only function of the points is to trigger a signal to the CD box. Have had the points in my 77 for 5 years, no problem. In the spring, I check the gap, rotor and cap, fire her up and good to go. I even have the original perma tune installed, and have had no problems with the ignition circuit ever..

Couldn't agree more I think they're junk.

[Hil911]

Maybe whip off your air filter and make sure that the CIS vane is moving completely freely. If it sticks near idle you could get this kind of outcome.

On my 1976 (as I understand it) the timing should be 5 degrees after TDC with the vacuum attached at 900 RPM. That is the line to the left of Z1 when viewed from the rear. When you press the throttle and the butterfly opens, the ignition advances rapidly. I've attached a diagram which was presented as 1976 timing in an earlier thread. Note that it starts at 5 degrees BEFORE TDC at 900 RPM. So it looks as though the vacuum isn't attached. Either way my guess is that you need to get from 5 degrees ATDC at 900 RPM with vacuum, to 20 degrees before TDC at 2000 RPM with the throttle partly open.

[Hil911]

And the diagram ...



Sorry - that's probably way more info than you were looking for.

[kach22i]

Originally Posted by gli_ryan

I got it to fire up, then I couldn't get it again. Seemed the magnet ring wasn't sitting properly, tried pushing it down so the rotor would stop hitting the cap and broke it. Put the points back on and fired it up, returned the pertonix. Thing sucked. I'll run the points and cdi. I've got a hanging idle now though. So need to get that to go away. Ideas before I start the search and track that issue down? Timing is set, vacuum advance isn't leaking. not sure.

You broke the magnet ring by pressing on it?

Were you pressing on it with a 3 lb hammer?

What is "hanging idle ", I am not familiar with the term.

Perhaps excessive pressing shoved the distributor shaft down too far and it is binding up now. I mean if you pressed down hard enough to shatter a magnet ring anything is possible.