944Ross

You might peruse this thread, to see in particular if the WP pulley could be wrong. It also has good pictures of how the belt should be tracking.

https://rennlist.com/forums/924-931-...clearance.html

mikey_audiogeek

Attachment 540879

See the difference. The slack is measured on the opposite side of the belt. With the spring tensioner, you wind the motor clockwise to TDC but DO NOT step it back anticlockwise before setting the tension. Major difference!

Cheers,
Mike

Mighty Shilling

Huh.... wierd....

mikey_audiogeek

Not that weird. I have found that using the correct factory procedure detailed above, the auto tensioner consistently gives the same results on my car as using the Arnnworx tool and the Arnnworx procedure.

Anyway, we now return you to your usual programming... Any news on the belt alignment issue?

Cheers,
Mike

Mighty Shilling

Thanks for the info, Mike...

bebbetufs

Interesting discussion guys.
No real news on the belt issue. My mental capacity has been usurped by work and the discovery of a oil leak. I am on top of these things now and returning to the belt tracking problem.

I would like to know the width of the spacer which goes between crank pulley and oil pump sleeve. Do any of you know?

St3mpy

Is this using the same belt you pulled off the car? Have you tried a different belt?

bebbetufs

yep. I'm on the third belt and second spring tensioner pulley.

Van

Might it be worthwhile to put a dial indicator on the WP pulley?

As you mention in the first post, it's very unlikely that the crank or camshaft is untrue. If you've tried two tensioners, and still had the problem, I'd investigate the WP heavily.

Is it possible that you have a washer or something on one the the three studs under the tensioner that's that's making it not sit flat?

944Ross

It might be worth a try to retract the tensioner enough that it just keeps the belt from jumping a tooth, and turn the crank by hand forward and backwards, watching where the belt starts creeping forward. I also wonder if turning it backwards it goes towards the inside? Might be a clue there.

bebbetufs

This was one of the first things I checked, it is not an unlikely scenario. Unfortunately it seems to be too easy a solution for my karma

Just to recap my original post:
The belt is moving toward the block and is only kept in place by the inner lip of the tensioner roller/pulley.

I have tried 3 belts, 2 new and 1 old water pump, 2 different rollers for the tensioner.

I have not tried changing the crank gear, the cam gear (which has a few nicked teeth) or the tensioner assembly.

This is an interesting idea. Trouble is that the belt was tracking perfectly when i cranked the engine by hand. It was only when I fired up the engine it went towards the block. I've not been able to figure out why there is such a difference. Perhaps it takes a lot of revolutions for it to move?

944Ross

Given the cantilevered nature of the tensioning sprocket with the auto tensioner, I'd be suspicious that the tensioner pulley bolt is not able to hold the pulley square any more, or there has been distortion of the arm. If you think how any forces on the pulley affect it, they would tend to bend the pulley in (towards driver's side) at the block end, which would make the belt track towards the block.

I think the problem is your tensioner, one way or another. Can these later cars be converted to the early (manual) tensioner setup?

Mike C.

I second that.

Van

Well, if he tried 2 tensioners and had the same problem, then it's probably not the tensioner. That's why I was thinking the mounting surface on the block was amiss.

Is this a new waterpump? If so, I assume this *didn't* happen with the old one? Any shaft movement in the WP? If the shaft was to tilt (bushings not doing their job), this should happen - the belt walking towards the block, I mean. Also if the WP pulley wasn't square on the shaft.

Belts like to go to the largest diameter - like the old leather belts of farm machinery that stay on those domed pulleys. If the timing belt is going towards the block, that means that your "running path" is longer closer to the block. If the WP shaft has play, the pulley will tilt a little with the radiator side of the pulley moving more than the block side of the pulley when the t-belt is tensioned. This would make the radiator side of the pulley be the shorter path - closer to a straight line - and cause the belt to move to the block.

Because the tensioner idler is mounted to the arm, if that bearing/bolt had play or flex, the block-side of the tensioner would make the shorter path - causing the belt to work its way towards the radiator.

Did you have any head work done when the car was apart? Could the head have been resurfaced at an angle?

944Ross

I believe he tried two tensioner pulleys.

The longer path would have higher tension, I would expect it to look for the shortest path.