928Myles

rgs944,
I beleive that there will soon be 3 options for (later) cam gears available:
1 - New Porsche design
2 - 928 Motorsports design
3 - In a couple of months 928'srus design should be available.

Myles

Bjbpe

Hi Phil:

I have an '87 S4; owned it since it was new.

Let me set your mind at ease. I've experienced loss in belt tension a couple of times (couple being two). In both cases the engine lost power, an indication that the valves are probably out of timing, but in both cases the belt was not broken. I replaced the belt both times and the car returned to its smooth operation. I think you will be OK. Good time to check the water pump. In my case, the water pump bearing was worn and needed replacement.

One fellow has a picture of a bent valve on his thread. He may not be as optimistic as I am.

Barney

Want to be

Tuesday i hope to get the timing belt covers off to see whats wrong.

1. Checking TDC
2. Checking the belts for teeth missing.

My guess it skipped a tooth or two.

Thanks for being optimistic...its needed.

Bjbpe

I'm still optimistic for you. In the case of the second experience, I too got a chattering sound and I was concerned that the valves were hitting the pistons. Still, being 77 years old and not wanting to spend any more than I had to, I replaced the belt and the water pump and went from there. Car runs as smooth as ever. I would, however, absolutely replace the belt and check the water pump. Another note, I purchased a belt tension tool from 928 International (the cheap tool - they have more than one) and it was very helpful.

Leon Speed

I think you'll be ok too.

Want to be

Today i was able to get the timming belt covers off. I believe i am off one or two.

Hopefully this is GOOD news.

Landseer

Where is the nick on the rear of the cam gear?
That is the alignment nick.

My belt warning triggered twice this week, cold, pulling out with heavy throttle onto highway.
Gotta replace this conti with a gates.

Lizard928

Re-string the belt and do a leakdown. Nothing else will tell you the truth.

Imo000

On an early 32v engine, you can skip 3 teeth on the passanger side and 4 on the driver......without any valve damage. This happened to me so, it's a first hand information.

Want to be

I circled the area i thought was TDC. The cam does not have a white mark on the cam. Can anyone verify.

I agree about the compression test. Its my next step after getting the belt on and installing a porken tensioner kit.

Lizard928

Forget the compression test,
do a leakdown test. Rent a compressor if you have to!

and you are correct about that mark, so you are 2 teeth off. I honestly DOUBT you have any damage.

docmirror

Look on the BACK of the cam gear for a small indent in the side of the gear: "V" It should align with the same notch you have circled. There are at least 30 threads on the belt service that have pics of this.

<edit: look at the about 8 o'clock position and you will see the small V shaped notch on the BACK of the cam gear. Align this with the notch on the backing plate on both sides.

PorKen

edit: never mind...tired, not thinking...

FredR

Phil,

Your photo may mean something if the position you show is correct but the correct alignment mark as others have said is on the back of the camwheel. Maybe I am missing something here but if the red circle is the correct "indexed" position for the crank on TDC, then whatever way you look at it, your belt appears to have jumped and there can only be a "bad" reason for this. Before anything else you need to determine why it jumped. The possibilities are very limited viz failed tooth on the belt, belt tension, failed water pump bearing- that's about it really. Did I miss anything?

Make sure you know where the index mark on the back of the cam wheel is, and if that is correct, then start to reason out why it has jumped what it has. There are 48 teeth on the cam wheel thus 15 crank degrees per tooth. Thus if you are two teeth out you are 30 crank degrees off the mark. Imre has passed a very interesting comment about what you can get away with tooth slip wise. If his observations are correct then you should be relatively safe wrt to piston/valve interference.
I think Colin has summed it up best- you need to get belt correctly indexed and then do a leak down test and take it from there.

Best wishes

Fred

Imo000

Since the factory warning system saved your bacon, why on Earth would you want to get rid of it and go with the Audi tensioner?