Ignition Problem

I am having problems with burning out my cap and rotors. Last year I had my engine rebuilt. After about 500 miles the new rotor burnt in half. I was about 350 miles from home so I had the car towed to the nearest shop where I thought the guy might have a clue. I had a Pertronix Ignitor, Crane HI-6 CDI, and a PS-92 coil. He replaced the rotor but it still didn't work,tried a new Ignitor still nothing, finally scraped the Crane parts and just went with a Bosch coil and Pertronix with no CDI unit.
After this the car ran ok but would not rev much past 4000 rpm after about another 500 miles. I finally checked and the rotor once again was almost burnt off. I then ordered up the proper expensive Porsche part with the rev rimiter and a new cap. I put those on, timed it, and have since put on another 3500 miles. The last couple days it has been sputtering worse and worse especially going slower around town. It still revs high but sputters on its way up. I looked at the rotor and found that it and the cap have carbon deposits on the posts. What could be causing this to happen? Could it be a failing distributor?
This is on my 76 911.

[This message has been edited by Gary Peters (edited 06-03-2000).]

This set of problems seem all related to a previous owner making 'improvements' in a system -- the same that my car has -- that needed nothing but regular maintenance on an annual basis!

I saw a Bosch CDI-unit sell for $61, recently on eBay. My strong suggestion would be to put back all of the factory parts your engine came with from the factory, then you will have no ignition-related problem revving to your 6500 rpm redline!!!

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Warren Hall
1973 911S Targa

I failed to mention that when I lift off the throttle the tach bounces around above the actual RPM. I had my cap off and found that the shaft could be moved up and down about 3mm and a bit side to side. It also looks like the rotor may have been hitting the cap.

Would it be worthwhile scrapping the whole distributor system and go with the crankfire system like what MotorMeister sells? I plan on keeping the car for a long time and if this one or a similar system were alot better ie more reliable I'd consider investing in it.

Has anyone tried similar systems? Any comments would be much appreciated.

BTW it still actually redlines it just sputters sometimes



[This message has been edited by Gary Peters (edited 06-05-2000).]

I think all your distributor needs is to be disassembled, cleaned, and have both of the bronze bushings in the body replaced! Please check the following thread for more info:
http://www.pelicanparts.com/ultimate/Forum3/HTML/001739.html

Once your distributor is 'rehabed' I think your problem will be gone, including any rev limitations caused by wobble and play in the shaft.

And, no, I don't think there are ANY benefits to expending bucks on a crankfire system!!! If maintained to specs, that distributor is good to 8000 rpm with the stock CDI ... that is what 330 hp RSR 3.0's used, quite reliably, often called 'legendary reliability,' for the hundreds of race wins over the past 27-28 years!!!

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Warren Hall
1973 911S Targa

[This message has been edited by Early_S_Man (edited 06-05-2000).]

Where can I get these parts from? Would a dealership carry a kit? I didn't see anything at this website.

The bushings are available at industrial bearing supply houses ... just take what remains of your old ones, the distributor housing, and the shaft with you when you go, and they will most likely be able to provide, based on precision measurements, a replacement set at very reasonable price!

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Warren Hall
1973 911S Targa

Thanks for the advice.

Today I took out the distributor and started to disassemble it. I got down to the springs and found the springs were two different sizes one had ten coils and was finer and the other had five coils but thicker. The thinner one was barely on. The retainer was partly broke and the spring came off easy. When I removed the smaller one the big spring would not return the weights. It wasn't sticking either just stretched. Tried to remove the big spring carefully and broke the retainers for that one as well. Are the springs actually supposed to be different sizes? That doesn't seem right to me. Where could I buy new springs and retainers?

Also, how did you get the shaft out? On the rotor end there appears to be a clip inside the shaft. How did you get it out to get at the bearings? Am I missing an easier way of doing it?


Are there any diagrams out there showing the parts in the distributor? Its a Bosch part #0 231 184 001.

Bump

Gary, I'm not aware of any available diagrams, but there is one that is 'close' in the Clymer '912 Handbook' ...

As far as the clip goes, a dental pick or something similar is rquired to get it loose and out ... watch out for launching it into 'orbit'!!!

The different springs sound right, since the 'curve' has two different sloped sections, and I don't know how they would manage that, otherwise!

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Warren Hall
1973 911S Targa

I finally got the shaft out. The thrust washers were missing (found pieces in the bottom)and the flyweight mounting plate has worn into the housing by probably about .020-.030". Would I be able to just polish it smooth and put in new thicker thrust washers? Is brass used for the thrust washer?

Thanks.

The thrust washers are hardened steel, and should be available at any reasonably sized industrial bearing supply house ... the ID is the critical dimension, thickness and OD, less so. There are always at least two thrust washers used.

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Warren Hall
1973 911S Targa