I just took my car to Pfaff Tuning yesterday to have my distributor and rotor replaced along with the belts. The parts came up higher than what was originally quoted to me and he explained that the orignal quote only had one distributor cap and one rotor. When installing the parts they realized that my 993 C2 requires two distributor caps and twor ignition rotors. Seems strange that a car has two distributor caps and rotors. Can anybody shed any light on this. Why are there two caps?

 

the stock set up is a twin plug.. what do you mean they don't know it was a twin plug. i would not take my car there.

lemon

 

How many spark plugs are down there?

 

I am surprised the shop didn't know already there would be two distributors - they cannot have worked on many 911's from the 89-97 era... it is one of the basic design features of that generation motor.

 

There are single distributors that have twelve plug leads but Porsche chose to go with a dual distributor system for the two sets of plugs on the 964/993. Why they did that (not enough room for the larger, single distributor?) I'm not sure.

I'm surprised your mechanic was not aware of the twin distributor system.

 

I was surprised too. He was the Technical Consultant (service advisor) and not the mechanic. I came to same conclusion that this shop is not necessarily good for older model Porsches. Will not be going there again.

 

Time for a bit of familiarization. I take it you never lifted the engine compartment lid.

 

I only saw the one cap.

 

well considering they are right next to each other, its pretty hard to miss the two of them.

 

Thats pretty scary considering Pfaff is one of the most prominent Porsche dealerships in Canada!

 

the idea for two distributors is not new and can be found on the famous Fuhrman engine that powered the early nineteen sixties Porsche Carreras. In the 1964 Carrera it provided "kill-switches" on the dash to check proper ignition. If you "killed" one of the distributors that way, the RPM dropped noticeable, thus showing that with twin plugs you are apt to get better combustion,thus more power. I was led to believe that the timing of the "firing' of the plugs was slightly 'offset'... maybe somebody with more knowledge can further enlighten us...my to pennies...

Bert

 

Lighten up guys! Let's not scare folks off with valid questions.

I see this as an excellent, low risk, learning experience for the original poster. They can't screw too much up with his dizzy cap / rotor and belts service. He said that he won't go there again. No harm done.

BTW, I recently replaced the dist cap and rotor on my car (turbos have one), didn't notice any improvement in performance, not that I was expecting any. Mine had about 40k miles on it.

 

Make sure you check the dist. cap bolts once a year. I remember reading some where on this forum that they loosen over time, sure enough i replaced mine last year and when i check this winter they had actually loosened quite a bit.

 

Kinda-sorta related, I built a hot rod 3.2l twin plug motor for my longhood. I had 2 MSD boxes, coils and a twin plug distributor (Dist cap has 12 wires...ala old jag etc). Anyway I had switches that would turn off the upper and lower bank of plugs independant of each other. Short story long, there was definately a difference running on 6 vs. 12 plugs. Probably 15hp dif by the butt dyno. Even sounded different.

 

I just changed my caps and rotors today. Used Bosch replacements. Immediate impression is the idle is much smoother. I want to say performance is improved, but I don't know if it really is, or if its just the sensation of being a happy owner who saved a small boat load of money doing things myself (and without extra nuts and bolts at the end!) instead of paying a shop to do it.

It's a very basic job. The only rough part about it is the space (or lack thereof!!) to work.





Whay do you guys think? Is there an increase in HP after swapping out 50k old dizzy and rotors?


Sorry to thread jack OP. Hopefully you'll be motivated to tackle the job yourself! If I can do it...