Rennlisters,

I am in the middle of my first timing belt replacement. Car only has 37K miles, but it's been years since the belt's been replaced. I'm not a very experienced motorhead so I'm working very slowly referencing John Pirtle's writup and the workshop manuals.

Bottom line is that after replacing the timing belt, my 45 degree marks (and the 0 degree notches) on the cams aren't lined up perfectly with the marks on the vibration damper. I'm off by a tooth on each sprocket.

Before the timing belt replacement, when the camshaft was at TDC, the notches on the cam sprockets lined up fine. I then rotated the camshaft to the 45 mark and made marks on the sprockets.

I have taken the t-belt off twice now, re-aligned with the 45 marks, and replaced the belt only to find the same thing -- off by a tooth!

I've stopped for the time being and will pick this up again next weekend, but I'm hoping that a Rennlister might have some pointers... Is being off by a tooth OK, or should I be persistent in getting it perfect. And/or is there some trick to getting it right?

Any comments are appreciated. By the way, bless Pirtle for this writeup -- I can see that I have avoided many pitfalls by leveraging experience.

I'm sure someone will help soon. The marks can't be off but I'm no mechanic so I will be watching too to see what's up. On of the things I learned after awhile and it seems you are already there is enjoy the process. With the help from the board you can always get the job done right. Any pictures of your beast?

Have you tried using clothes line pegs to hold the belt on the sprockets as you install the belt? This should ensure the belt doesn't jump as cams try to turn away from the 45 BTDC marks. Let us know how you get on, it's the next part of my repair...

When you install the belt, with the crank @45deg and your applied ref marks on the cam cover ref marks - it is all too easy to be out a tooth!
Assure the crank is locked in at 45 deg. Then starting at the crank with the TB, thread on counter clockwise, keeping full tension on the TB. When it comes time to wrap around the left hand cam gear (1st in order), have a large wrench (32mm?) at the ready to rotate the cam ever so slightly clockwise! (~ 1 tooth).
The belt teeth will mesh with the cogs at the magical spot , and you can release the wrench/return the cam to the reference mark: secure the belt with a small spring clamp/tie wrap.
If done correctly, the belt is at firm tension and within 1/4 tooth of the mark. Repeat for the other cam, again using a spring clamp. Wrestle on the tensioner, apply enough tension to keep all together, and hand rotate as many times as it takes to satisfy you that the timing is correct!
Then repeat the rotations ad infinitum as the belt is tensioned....

Garth, I'll have to double check the WSM, but I believe it says once the cranked is locked the cam gears can be rotated counterclockwise?

Once the crank is at 45 degrees there is no interference, and the cams can be spun in any direction without worry.

Thanks everyone for the help. So here's what I did...

First, I tried to compensate and put the cam sprockets one tooth off position prior to putting the belt on. I didn't quite get what UKKid35 was saying about the clothesline pins, but I think it was to hold the belt on the sprockets while working on it... I didn't have clothesline pins, but I used some clamps to hold the belt on the sprockets and when I was done, I was ONE TOOTH OFF again, but in the direction I compensated. This told me what I was doing was going to work if I did it normally.

So I put the sprockets back at my 45 degree marks and put the belt on (using the clamps

Thanks everyone for the help. So here's what I did...

First, I tried to compensate and put the cam sprockets one tooth off position prior to putting the belt on. I didn't quite get what UKKid35 was saying about the clothesline pins, but I think it was to hold the belt on the sprockets while working on it... I didn't have clothesline pins, but I used some clamps to hold the belt on the sprockets and when I was done, I was ONE TOOTH OFF again, but in the direction I compensated. This told me what I was doing was going to work if I did it normally.

So then I put the sprockets back at my 45 degree marks (like normal) and put the belt on (this time using the clamps to keep the belt on the sprockets as I threaded it around) and what do you know, I was dead nuts on! After putting the belt on, everything was put back together (seemed like it went a lot faster after that).

While I was in there, I upgraded my spark plugs to the Platinum 4's. To my surprise, when I was done, a turn of the key and BWAHHHH! Hallelujah!

Thanks to John Pirtle and folks for the writeup, it was my bible, and proved that folks without much wrenching experience can follow directions and do this procedure!

Cheers everyone!

I don't remember where I read about this, but when I did mine, I used these bolts to hold the cams in place. I just installed them before I pulled the belt off.

This should work on any 32 V 928 motor, just make sure there is nothing like a hall sensor behind the sprocket!

T_Max,

I totally wish I'd done that, would have saved having to re-align a couple times!

I've put on and removed a new cam belt six or seven times in the last couple of days. The tensioner has been fully installed from the start, each time I left the right sprocket to last and slipped the belt 1/4" on to the top feeding it round towards the tensioner. Once the belt was 1/4" on all the way round I could tap it back in to place. After the first attempt I could do this very easily in under a minute. (I didn't even try the clothes line clips)

I was amazed how the tiny notches at the back of the sprockets aligned absolutely perfectly when at TDC, not even 0.5mm out.