Timing belt alignment woes

Yellowstone Savage · Post by **Yellowstone Savage** » 12 Apr 2012, 18:57

Hi! I'm installing a new T belt after replacing my water pump and tensioner and now I am having trouble getting the cam marks to line up.

First I line up the crank marks, put the intake cam on it's mark and then feed the belt over to the exhaust cam. With the exhaust cam on its mark the belt is either too tight or too loose. When I rotate the exh sprocket clockwise a tad it goes past the mark when the belt seats. I've rotated the exh cam repeatedly (by hand) and still have similar problems. I've rotated everything via the crank two times and the belt is still slack between the cams when the crank marks are lined up.

I've not released the tensioner yet, will that pull the exhaust cam counterclockwise and take up the slack? If they don't quite line up is it better to have the exhaust sprocket just before or just after the notch?

1997 - 850, non turbo

Post by **tjts1** » 12 Apr 2012, 22:08

I'm surprised people haven't adopted the whiteout method to timing belt alignment yet. Oh well.

Post by **rspi** » 13 Apr 2012, 09:19

All of the preceedures that I have seen instruct you to pull the pin on the tensioner prior to turning the crank 2 times. Pull the pin and if one of the cams are 1/2 knotch off you should be ok. Some people actually advance or retard a cam a full tooth to adjust their preformance.

Hope this helps and make sure those marks (all 3) are close before you turn that starter.

Gubernaculum · Post by **Gubernaculum** » 13 Apr 2012, 16:27

tjts1 wrote:I'm surprised people haven't adopted the whiteout method to timing belt alignment yet. Oh well.

Ha, I thought I made that up myself. It was clutch knowing exactly how many belt teeth should be between the intake and exhaust cam marks. I think mine was 18, but don't quote me on that.
To the OP: Yes, I think you'll need to tension the belt using the tensioner to get a better feel for where you are. My car has the later variable exh valve timing so the marks were tricky to get lined up as the exh cam had a different "feel" and springyness to it.

Yellowstone Savage · Post by **Yellowstone Savage** » 14 Apr 2012, 18:25

OK. I lined up all three marks, installed the belt, released the tensioner and rotated the engine by hand (socket on crank) twice. Everything looked good so I cranked it. My problem is that it runs noisy -- did not sound that way before I started. Did I damage a valve by repeatedly turning the exhaust cam clockwise earlier? Before moving the cam I always made sure that the crank mark was in line.

: Crank lined up.

: Cams lined up.

BTW - this all began so I could replace a noisy/leaking water pump with a new Hepu pump. That went fine, no leaks.

Post by **erikv11** » 14 Apr 2012, 18:42

If the crank is on the mark then you can turn the exhaust cam all the way around, all you want (but I wouldn't, just to be careful ...). SO you should be OK there.

Cam marks look good, I can't tell about the crank mark from the picture.

What kind of noise is it making? Are you sure the serp belt is back on properly?

Yellowstone Savage · Post by **Yellowstone Savage** » 14 Apr 2012, 19:31

Thx. I'm no expert on engine sounds but it's a tapping noise, louder than 'normal'. Didn't install the serp belt yet, so that rules out the alt, AC, PS.

Post by **rspi** » 14 Apr 2012, 20:46

Record the sound with a good Smart Phone and post it on Youtube or somewhere.

It's very common for people to think their motor is noisy after doing a timing belt job.

Yellowstone Savage · Post by **Yellowstone Savage** » 18 Apr 2012, 16:21

Thanks! The tapping noise went away after the engine ran for a few minutes. Final assembly detail - I need to install the timing belt guard. I'm not sure if I have the right 10 mm bolts, the long design of the ones in the pic doesn't make sense. Did I mix them up with something else I took apart?

mrjacobrussell · Post by **mrjacobrussell** » 18 Apr 2012, 22:07

On a 850 or v70 they are way shorter than the ones pictured