ThomasC2

When I checked the distributor drive belt the other day (looked really fresh BTW) I saw that the caps were pretty worn. Should you change them at any given milage or do you just change when it's time? I haven't found any info on this in the manual, books etc.

DaveK

I'm not sure "when it's time" is. I suspect in most cases, it's when the car starts misbehaving.

When I bought my car I had idle hunting (and stalling) problems which turned out to be due to worn caps. I also had some running problems a year or two back, and replaced a few things - including the caps - while tracking it down.

If you know they are pretty worn, then my advice is to replace them rather than waiting until they start to cause you problems.

Smokin

Sorry for being off topic... But Dave.... Your avatars keep getting better and better! WOW!

ThomasC2

Dave, I'll change them even if the cars goes like rocket, that's why I was a bit surprised when I saw what the caps looked like. My question was more if there are recommendations from Porsche or of it's just a part you change when you need to.

...and I like the avatar to! :-)

DaveK

I get the impression that they are not a serviceable item. If they were, I don't think mine would have been so worn out when I got the car.

She's even better in person.

Rennen

I think it depends on what you know about the last time they were replaced. If you're not sure, and they look worn, I would replace them now. they're a relatively low cost item, easy as pie to replace, and you'll definitely be regretting a decision not to replace them if you end up arcing out and stalling in a remote area or out on the highway.

Arrivare

Don't forget to change the rotor arms at the same time!
Regards
Allen

ThomasC2

Thanks Allen, I've planned to change the rotors to.

But still, are there any recommendations from Porsche about changing the cap,. like adjusting the valves every 20.000 KM. Or is just to do it when you need to? Does any one now? I'm just curious!

springer3

The rotor and cap should be maintained or replaced long before driving problems develop. Same for the spark plugs. Electronic ignition systems will fire a plug in oil, so sparking is not the problem. The problem is that it takes about 4000 volts to fire a new spark plug in a healthy ignition system, and two or three times that for worn or dirty systems. The ignition system will generate 50,000 volts (typical, I don't know what the 964 system does). Replace the parts early, and you avoid damaging voltage stress on the coils plug wires, and electronics driving the ignition. Those are the expensive parts to replace.

30,000 miles is about the limit for cap, rotor. and plugs. If you are really cheap (like me), you can clean and gap everything, and go another 20,000 miles. Wires last a long time if the firing voltage is kept low. Maintain the caps, rotors, and plugs, and the wires, coils, and electronics don't age much. They could last the life of the car.