timing belt question
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From: St. Louis, MO
timing belt question
I have a timing belt question. I have attached some pics of the drivers side and passenger side. As you can see the belt is running right in the middle of the gear on the drivers side and very close to the back of the cam gear on the passenger side. Is this normal? I always thought they ran in the middle. If this is not normal, what would be causing it?
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From: St. Louis, MO
I am planning on dumping this Conti belt for a new Gates. The Conti looks to have a slice of some sort on the smooth side of the belt. Not sure what from, but enough to freak me out and change it. I will have all of this off to change the belt, but not sure what to look for. I will post pics of the slice.
The WP is another 928INTL rebuild that was swapped out after the last new rebuild I got from them migrated and machined my block a bit coming home from SITM.
I do have a Porkensioner on here. All Audi parts were changed again last year after the SITM fiasco with the WP failure.
The tensioner pulley should not be guiding the belt since it is smooth, right? The only guides would be the WP and the crank pulley.
The WP is another 928INTL rebuild that was swapped out after the last new rebuild I got from them migrated and machined my block a bit coming home from SITM.
I do have a Porkensioner on here. All Audi parts were changed again last year after the SITM fiasco with the WP failure.
The tensioner pulley should not be guiding the belt since it is smooth, right? The only guides would be the WP and the crank pulley.
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S4's have a Hall sender plate behind the passenger side cam gear. This causes the gear to reside a bit further out and the belt to ride further back on the passenger side gear.
Judging by the distance of the belt from the front edge of the gears, this looks about right in terms of the difference. I really can't see the back edge on the passenger side gear, so I used the front edge as the reference.
The belt looks dead center on the driver side gear.
Judging by the distance of the belt from the front edge of the gears, this looks about right in terms of the difference. I really can't see the back edge on the passenger side gear, so I used the front edge as the reference.
The belt looks dead center on the driver side gear.
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How old is that belt? The back side looks, well, scuffed. How old is the water pump?
I see a pronounced imprint on the backside of the belt coincident with the location of the teeth. Can't say I've noticed a wear pattern like that before. My belts always look smooth and clean on the backside even after 45K miles and 9 years. Maybe it just some dirt/oil that got on the roller, but it's new to me and the belt surface looks uneven.
I see a pronounced imprint on the backside of the belt coincident with the location of the teeth. Can't say I've noticed a wear pattern like that before. My belts always look smooth and clean on the backside even after 45K miles and 9 years. Maybe it just some dirt/oil that got on the roller, but it's new to me and the belt surface looks uneven.
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From: St. Louis, MO
I pulled all of the pulleys off and balancer, but have not pulled the crank gear since last year. What are you thinking??
The passenger gear does sit a lot closer to the cover back than the drivers side. Can someone check their S4 for comparison.
I just measured the distance from the belt to the edge of the cam gear with some calipers. The passenger side is 4.0mm and the drivers side is 3.2mm. There is a difference, but is this not enough to worry about. Maybe it just looks a lot worse than it actually is due to the passenger cam gear installed position being different for the hall sensor.
The passenger gear does sit a lot closer to the cover back than the drivers side. Can someone check their S4 for comparison.
I just measured the distance from the belt to the edge of the cam gear with some calipers. The passenger side is 4.0mm and the drivers side is 3.2mm. There is a difference, but is this not enough to worry about. Maybe it just looks a lot worse than it actually is due to the passenger cam gear installed position being different for the hall sensor.
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Yes, the backing plates are different, so use the front of the gear as a reference, as you did and found little difference, accounted for by the Hall sender plate.
500 miles??! Jeez, that belt doesn't look very fresh. But 500 miles in a year? Maybe that's the problem. You need to drive it more!
500 miles??! Jeez, that belt doesn't look very fresh. But 500 miles in a year? Maybe that's the problem. You need to drive it more!
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Tell me about it. I worked on the car for over 6 months straight and got everything done for SITM 2008. It was a blast and a long drive from MO to NC. I did all the PC on the engine, plus a new WP and TB. On the way back from SITM, the WP gave away and migrated. I barely got home. After that failure, I was pretty soured on working on the 928. It took me a couple months to get it driving again, and then winter came. I am just now getting around to finishing some other things when this came up.
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I just did the whole front-end service on my GT a few weeks ago and I do recall the belt riding closer to the plate on the passenger side (as Bill said because of the hall sender). I don't remember it being flush with the back of the cam gear though... How many times did you rotate the engine around? Did you install new tensioner arm bushings?
Oh you have a PK'er in there, never mind about the bushings then. One thing is I installed a Gates belt as opposed to your Conti... Could you take a picture of the belt looking down at it from the top as it goes onto the water pump pulley from both sides?
Dan
'91 928GT S/C
475hp/460lb.ft
Oh you have a PK'er in there, never mind about the bushings then. One thing is I installed a Gates belt as opposed to your Conti... Could you take a picture of the belt looking down at it from the top as it goes onto the water pump pulley from both sides?
Dan
'91 928GT S/C
475hp/460lb.ft
Last edited by dprantl; May 6, 2009 at 11:09 PM.
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The wear looks too much considering the low miles. Something is wearing the top of the belt and the pump roller is the only possibility.
The tracking to the rear is concerning.
Is the roller on the WP moving towards the casting?
The tracking to the rear is concerning.
Is the roller on the WP moving towards the casting?
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Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission?
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928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission?
George Layton March 2014928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
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The reason I asked about the crank gear, there is a spacer/guide that is in the front, and rear of the crank gear. If the rear one is missing, it might be the reason the passenger side is tracking much differently that the drivers.
Looking at the rotation of the belt, that was the only thing I could think of that would cause that with the PK on there.
Looking at the rotation of the belt, that was the only thing I could think of that would cause that with the PK on there.
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