Dizzy Cap Issues. Rotor arm catching no.2 terminal

[ChasR]

My 944 just got a new Dizzy cap on today after reading Oli's Post. Sure enough my old one was past it with blackened terminals (a 1998 cap according to the date stamp), but whilst it starts better (it needed a little coaxing before) I now have a new problem

The rotor arm catches on the 2nd cylinder's cap terminal (or the bottom left terminal if you look at the cap from the front of the engine and imagine the cap is transparent). It makes a racket, and I was greeted with shards of brass inside the dizzy cap. If I leave the screws on loose and lift the cap from the bottom it stops scraping. It seems the old cap had exactly the same problem since that also has a deep groove in the No.2 terminal, so I am fairly sure that the cap is not to blame.

My next question is if it's not the cap, what else can it be? My Rocker cover has been repainted at some point to look like a Ferrari item but it seems quite clean/bare metal) around where the cap goes and that is a snug fit. Failing that, is there anyway to align the rotor arm correctly? Mine is held on by 3-4 allen key screws. The rotor arm is still a Bosch item.

 

[zcacogp]

Chas,

First off, apologies if my post has caused you problems. The replacement cap fitted mine without any issues at all, and works deliciously.

If it happened with the last cap then I'd suspect something is up with the distributor. And if the cover has been off then that could be the explanation. The cap is located on a raised lip which is part of the front of the distributor, and the three screws just hold it home. Is it possible for the cover to be a mm or so out?

I'd expect the rotor arm to be fairly centrally held on the distributor spindle so I doubt that would be out. Unless the spindle is somehow moved within the housing ...

Is it possible to take the housing off altogether? That may tell you something.


Oli.

 

[ChasR]

No apology needed Oli. The cap has highlighted a problem the car has had before. When you say the housing, I assume that you are referring to what the dizzy cap sits on? I will admit that the rotor arm does not seem to sit dead on centre when the cap is off, so if what I think what you are referring to as the housing being a 1mm or 2 out, that would explain quite a bit. Still, amazing that PH didn't detect that during the last cambelt change.

 

[zcacogp]

Chas,

It is indeed odd that PH didn't spot it, if they were the last ones to fit a cap. You wouldn't be able to miss the sort of noise I imagine it made ... []

Yes, I'm referring to the bit of tin that forms the outside of the distributor itself. If it has been bashed, or not put on straight, then it would cause the cap to be off-centre. However I have no idea how this is attached, or even if it is an integral part of the distributor itself. I don't know whether it being squiff is even a possibility.

The naughty side of me says that if the old cap 'wore in', the new one will too. But that is botchery of the first order. As would be the idea of packing the cap up a little so that it clears the rotor arm.

How about taking the cover off and having a look at the inside? Referring to the Porsche Parts Diagram if need be. That would be my preferred route forward.


Oli.