Pertronix HELL!!!!

sean m · sean m's Garage

OK, here we go........
Background: Car is a 77S, Pertronix unit previously installed, wire broke. Replaced unit(all to specs).

Got dizzy set up correctly (pointing at notch), pulley set to TDC, bought a Craftsman advance timing light to get timing correct, car fires up, idles at about 200.

I know that to set the timing I need to be at 950. I can't get the idle up. I've turned the idle screw around and around....car won't idle correctly. obviously, I can sit in the car and push the gas to get there, but I know that's not what we're after.

I've moved the dizzy as much as possible, it does get the idle a little higher, but no where near high enough.

I've read the threads.......some people swear by the pertronix, some swear at IT and go with points.

Took the car out today, it's like the RPM's never get where they should be. I normally shift at about 4000, it never gets there. It's like I'm using half the engine!

I'm sure someone can point me in the right direction.

Next step......take it to someone that knows what they're doing.....

As always, any help is appreciated.

Joe Bob · Joe Bob's Garage

Dwell?

Zeke · 01-31-2009, 04:10 PM

Did you have the distributor out? If so, I'd bet a dollar to a donut that you're one tooth off.

sean m · sean m's Garage

Milt.....I've adjusted up a tooth and down a tooth......won't start either way. Will start only in this position

RSTarga · 01-31-2009, 05:24 PM

That distributor needs a rebuild

sean m · sean m's Garage

RSTarga......that's not my distributor, just a picture I used to show where the rotor was pointing.

kwikt 911 · kwikt 911's Garage

Tried a Pertronics in my 72 and didn't like it. Runs better with points. JMO!

Kevin

Walter_Middie · Walter_Middie's Garage

Sean,

Pertronix is a great improvement over points. Theoretically, if the points were working correctly and never moved, they should work OK, but for me, Pertronix got rid of the constant fiddling with the points.

In the picture of the distributor you included, notice how the rotor points to the mark, AND the adjustment is in the middle. Are you saying that after you move the rotor one tooth, you cannot line up the rotor and the mark with the adjustment in the middle? Even after you advance the distributor slightly?

Are you checking the timing with the vacuum hose disconnected and plugged?

Once you get the air gap on the Pertronix correct, and the distributor in with the timing set, you will be fine. This is all really basic, so keep at it. It's nothing major. And don't drive it until you get this correct - you won't hurt anything, but you will be disappointed.

911Rich · 02-01-2009, 06:11 AM

POSSIBILITY 1:
Your distributor is off, you need to find TDC and set it right, if you aren't familiar with those rev limiting rotors they can be tricky because of their odd shape. A slight misalignment at the crank will make a drastic degree difference at the rotor shaft.

POSSIBILITY 2:
If you're sure TDC is correct make sure the rotor shaft hasn't separated at the counterweights inside the dist, this is very common in tired distributors, pull up and down on the shaft to check for excessive play, also check its rotation by hand to see if it skips internally. I've also seen issues where the pertronix has been forced onto the shaft(some fit really super tight) and the wheel/magnet triggers for each cylinder end up off, recently I also had an issue with a DIYer who pounded a pertronix onto the shaft so hard it literally damaged the shaft/bushing/weights resulting in a complete dist rebuild.

I will say that Pertronix's fit seems to have gone down the tubes in recent years, almost as if the unit is made to small for the shaft.

Good luck
R

sean m · sean m's Garage

Walter..
"Are you checking the timing with the vacuum hose disconnected and plugged?"
No, I couldn't get the timing correct because it never would idle at 950.....figured I should get this corrected first before going to advance timing.

Rich.....
POSSIBILITY 2:
If you're sure TDC is correct make sure the rotor shaft hasn't separated at the counterweights inside the dist, this is very common in tired distributors, pull up and down on the shaft to check for excessive play, also check its rotation by hand to see if it skips internally. I've also seen issues where the pertronix has been forced onto the shaft(some fit really super tight) and the wheel/magnet triggers for each cylinder end up off, recently I also had an issue with a DIYer who pounded a pertronix onto the shaft so hard it literally damaged the shaft/bushing/weights resulting in a complete dist rebuild.

It's at TDC, not much play.

I did however, notice a couple things on the Pertronix.......
When I put in my "old" magnet from my original Pertronix, it fires up (runs rough, but starts). When I use the NEW magnet...nothing.

In the instructions for the Pertronix it states that the magnet bottom should sit even with the bottom of the unit.....my magnet sits way lower than the bottom of the unit.

This was the correct unit from Pelican.....I guess I'll call Pertronix tomorrow to see if I'm missing something.

911Rich · 02-01-2009, 08:37 AM

Have you had the dizzy out and rechecked the shaft?

Joe Bob · Joe Bob's Garage

Pertronix sucks. I would go with a later dizzy with a built in electronic ignition, stay with points or go with MSD.

Walter_Middie · Walter_Middie's Garage

Quote:

No, I couldn't get the timing correct because it never would idle at 950.....figured I should get this corrected first before going to advance timing.

Sean,

Don't wait to get a timing light on it. The reason it doesn't idle at the correct RPM is because the timing is not correct.

If you can get it to run with the old magnets, why not use those? Why are you changing Pertronix? Something wrong with the old one? If your magnets sit too low, maybe that is your problem.

the · 02-01-2009, 09:09 AM

Quote:

Originally Posted by mikez

Dwell?

How can there be a dwell issue when running Pertronix?

In theory, Pertronix is great. In real life, a lot of people have had problems with it, going back at least 10 years now. I remember we installed on on a friend's 914, we couldn't get it running, turned it back in and they found it was defective. Pertronix sent another one, and that one turned out to be defective, too!

I'd replace the Pertronix with a Crane XR700 or similar (http://store.summitracing.com/egnsearch.asp?N=400078+304618+115&autoview=sku). These are very reliable, your car will run great with it.

911Rich · 02-01-2009, 09:46 AM

Quote:

Originally Posted by the

I'd replace the Pertronix with a Crane XR700 or similar (http://store.summitracing.com/egnsearch.asp?N=400078+304618+115&autoview=sku). These are very reliable, your car will run great with it.

I agree, I like the Crane XR700 optical ignition set up, I've been using them for 20 years on both Porsche & Rolls-Royce with nearly 100% reliability.
The Pertronix is only popular because its "supposed" to be a simpler installation...

wowzer911 · 02-01-2009, 09:49 AM

Are you sure that you recieved the correct Pertronix unit for your 77?
Ignitor part #1867 (black), or if you purchased the Ignitor II (adaptive dwell feature) part #91867 (red)
Have you left the ignition switch on for an extended time without the engine running?
Have you checked for a low voltage problem?
When I installed mine I had to call cust. service, they were very helpful 909-599-5955

Zeke · 02-01-2009, 09:50 AM

One thing you CANNOT do with pertronix is leave the key on with the engine not running. They will last less than 60 seconds. Even a shop I used to go to burned one up on my 914.
I had forgotten this until just now.

911pcars · 02-01-2009, 10:08 AM

My suggestion. Try to isolate the cause of the symptom, whether it's the Pertronix, incorrect timing or whatever.

Revert back to the breaker point setup and try it again. If you still have issues, it's not the aftermarket ignition. Start from this point and make sure the distributor and rotor are in the correct position (timing is difficult to obtain otherwise), points are adjusted correctly, firing order is correct, plug wires are connected, etc. all the basic stuff.

Don't be tempted to diagnose your way out of this by buying new stuff unless your checkbook needs exercise and/or you want extra parts.

Sherwood

tmctguer · tmctguer's Garage

Don't be tempted to diagnose your way out of this by buying new stuff unless your checkbook needs exercise and/or you want extra parts.

Sherwood[/QUOTE]

That is one of the best lines I've ever heard. i will keep it close to my heart forever.

I am EXTREMELY happy with my Pertronix installation, so i am quite sure this is something very simple. as a previous poster said, the air gap is important, as is the height of the pertronix unit.

are you getting spark at all of your plugs?

Joe Bob · Joe Bob's Garage

Quote:

Originally Posted by the

How can there be a dwell issue when running Pertronix?

In theory, Pertronix is great. In real life, a lot of people have had problems with it, going back at least 10 years now. I remember we installed on on a friend's 914, we couldn't get it running, turned it back in and they found it was defective. Pertronix sent another one, and that one turned out to be defective, too!

I'd replace the Pertronix with a Crane XR700 or similar (http://store.summitracing.com/egnsearch.asp?N=400078+304618+115&autoview=sku). These are very reliable, your car will run great with it.

I meant when he put the points back in....