Pertronix install - big backfire - 1977 2.7L

[kach22i]

I just installed the Pertronix Ignitor kit.

I followed the CDS instructions, black ground wire to where the points wire went to, and ran the red wire to the open spare in the electrical/fuse box in the engine bay.

The only question I really had before starting was; is there a polar orientation to the round magnet? Is there a right side up?

The kit is all installed, I turn the key and she cranks, and she cranks...................and she cranks. Just as I am thinking perhaps I should just lay off KABOOOOM! Like a gun going off, the loudest dang backfire I have ever heard. Scared the hell out of me, the people living next door came out and said; What wast that? It's only me I said sheepishly.

I checked under the cap, no damage, no problems.

I tried it again, a few much smalled backfires, and she starts to turn over. I don't want to give it too much gas as I think it will only lead to creating a large backfire so I let it stall out a couple of times.

Has anyone else gone though this?

Before I blow up my car, what should I do?

[JP911]

The magnet should only fit one way. It needs to "snap" down snugly in place. If it does not, the rotor may be sitting too high and not making proper contact. I ended up grinding down the bottom of my rotor bay about 1-2 mm. Also, make sure to check the order of your plug wires (if you removed them from the cap). I accidentally re-connected my plug wires in SC orientation (SC dizzy spins counterclockwise) and just couldn't figure out why she wouldn't start...

[kach22i]

I was very careful when I changed the cap out and replaced the rotor. The order of the wires I will have to double check in one of my books just to be safe.

The magnet did snap into place, but I kept thinking about the instructions saying to rotate until you feel something then push down.

Rotor sitting too high..............interesting idea, I'll look into that to.

I may of threw everything out of wack when tighting down the screws the whole inner assembly moved for a monet but then went back into place. It happened so quickly without warning that I just put it out of my mind. Wondering if it skipped a beat somehow.

Magnet note: There are four small dots I placed those face down, the single set of serial number facing up.

[JP911]

Try fiddling with the magnet a bit. Also, pull the manet off, seat the rotor and eyeball (or somehow mark) the heighth, reinstall magnet, reinstall rotor, and compare heighth.

[kach22i]

Originally posted by JP911
Try fiddling with the magnet a bit. Also, pull the manet off, seat the rotor and eyeball (or somehow mark) the heighth, reinstall magnet, reinstall rotor, and compare heighth.

I'll start there, will be back in ten minutes.

[buster73]

Sounds like your ignition timing is off. You can turn the distributor housing "by ear" just to have the engine running smoother again, but should adjust properly using a strobe a.s.a.p. Also make sure you have not blocked the movable adjuster plate (advance) when fastening the pertronix unit.

[kach22i]

Too high.

The center spring tensioned dickie up the the cap was pushed up and jambed, I had to pry it lose.

The rotor was sitting way too high. I am guessing 1/2" too high that's the height of the magnet.

I slipped on the old and new rotor, plus set them toe to toe, they are equal.

How is the rotor supposed to function set that high?

The magnet slides down to the bottom of the shaft and lines up with the magnetic puck-up black box with the two wires sticking out of it. This sets everything 1/2" higher..............what's going on here?

[JP911]

Sounds like the magnet isn't seating properly. A half inch is way too high...too high to even grind down the rotor at the base. The magnet should really "click" down into place. All I can suggest is to keep messing with the magnet to see if you can get it to go down a bit more and then possibly grind up to an 8th of an inch off of the base. You do have the side with "hexagon" (six-sided shape) cut into it facing down, right?

[kach22i]

Originally posted by JP911
Sounds like the magnet isn't seating properly.

You are correct sir....thank you very much.

The car is running now and not too poorly either. Time for a test spin, but it's already dark so i'll make it short.

The part I did not understand was when the instructions said feel. There was no feel when rotaing at the round top part of the shaft. The instructions said don't go all the way down before "feeling" the notch. That's what I did the first time, but failed to realize the big picture.

I might be taking it down that 1-2 mm, and might pick up a spare rotor while I am at it. Cheers JP911 and others, you have been great.

[JP911]

Sweet! Glad I could help out. This was a project I recently performed myself and had a few hiccups, similar to yours. I got it working and the car runs better than ever!

[Zeke]

On the 914 dist's, we had to PUSH the thing down hard. It doesn't want to go, but it has to. That's why you line it up before gettin' down on it.

[kach22i]

I forgot to regap the distance with the provided tool (plastic stick) the second time around because I was in such a hurry. This might account for the no low end power I experenced in the test drive.

Also trying to start the car without the magnet properly seated may of cause permature wear of the rotor, the cap looks good though. The rotor should have a little more metal sticking out than the old one, but I swear it's less.

I think I'll order some spare parts (rotor, cap and Ignitor spare kit), I already have spare points to be on the safe side.

Once I'm satisfied that I've tweeked the install to it's proper setup, then the timing/dwell will be reset. I have never done the timing on a car before, and this little experience tells me my car deserves a better mechanic than me. Time to place another call to my father-in law and make his retirement more fullfilling.

One good thing out of this, is that the next guy to try this kit will see what the last guys mistakes was and avoid it. I would of swore on a stack of bibles it was all the way down the first time, twist and push, twist and push down hard. Just don't take a hammer to it, I don't want to be responsible for that one.

[kach22i]

I just ordered a new cap and rotor. I don't know if I'll keep them as spares or try taking 1-2 mm off the bottom of the rotor.

I just want a fresh start, not 100% sure if there is any harm done when I tried starting it without the magnet all the way down.

For the cost of a fill up, I'll take the fresh start approach.

PS: If there are any other tips or things to look for, things not to do, etc...........keep them coming.

Final note: when you are all through checking the connections on the cap, check the first spark plug wire on the left (drivers side). I found that I pulled off that plug wire by accident. The car really runs better on 6 cylinders, not five.

[kach22i]

UPDATE:

Originally posted by JP911
and then possibly grind up to an 8th of an inch off of the base.

It's works..................1/8" is a bit much but my belt sander got the better of me and leveled off at 1/8".

I regained my low-end power and that was with grinding the old rotor as an experiment!

I think 1/16" of an inch off the new rotor is what I'll try next. This is just like trying to get the best sound out of an old turntable.......love it.

[RoninLB]

fwiw,
I just did the Pertronix install. I extended the wires to a wire connector block on the rear elec panel. I will have the back-up Pertronix and points wires extended for a quick R&R.

[pwd72s]

Ron, I'll never get tired of looking at your wiring work.

[}{arlequin]

does anyone know which Pertronix kit I need? It's a stock 2.4cis so I'm assuming it's a stock dizzy too.

[RoninLB]

I used xxxx

rev limiting rotor can be a pia. Don't follow instruction sheet.

ps: pn 1867

[}{arlequin]

Ron, their site lists 1847 as an application for a 4 cyl motor. How does that work in a 911?

[RoninLB]

Originally posted by }{arlequin
Ron, their site lists 1847 as an application for a 4 cyl motor. How does that work in a 911?

I was reading off the instruction sheet. Wrong

1867

ps:Ignitor Electronic Ignition For Bosch Distributors: 0-231-184-001, 002, 003 and 004, 911E/911T/911S (1973-75), Each $69.85
PEL-PT1867