Camshaft Sprocket Wobble... HELP!
07-10-2006, 09:14 AM
#1
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Camshaft Sprocket Wobble... HELP!
All,
First and foremost: I am a 3 year reader and, ashamedly, first time poster. I read AW everyday, especially now that I finally own the 2.8 B5 A4 that I'd had my eye on forever. AW has definitely been an invaluable resource. So, THANKS!
On to the good stuff. I have had my car in service position for the last few days working on the usual suspects. I replaced:
- Serpentine belt & tensioner
- Valve cover gaskets
- Cam adjuster gaskets
I bolted everything back together yesterday and fired her up. Much to my dismay, the driver's side camshaft sprocket is rotating with a very visible wobble. Passenger side appears to be fine. The problem is that I'm not sure if this was an existing issue or if I caused the problem. I can't think of anything I could have done to cause it. I did not remove the cams or timing belt to do the service. I DID loosen the cam bolts on the passenger side to help lift the tensioner, but I didn't do this on the driver side. Worth noting that the driver side tensioner did not immediately spring back up after removing the 3366 compression tool. Others have noted this and that the oil pressure will most likely extend it. I still don't believe this could cause the wobble, but I'm not sure. I'm also noticing the "tin marbles" chatter from both heads now... and I've let the motor idle for about 3 min.
Any help on the issue would be welcomed (theres not much existing info on camshaft wobble). Figured I'd ask AW before risking a drive to the shop. THANKS!
First and foremost: I am a 3 year reader and, ashamedly, first time poster. I read AW everyday, especially now that I finally own the 2.8 B5 A4 that I'd had my eye on forever. AW has definitely been an invaluable resource. So, THANKS!
On to the good stuff. I have had my car in service position for the last few days working on the usual suspects. I replaced:
- Serpentine belt & tensioner
- Valve cover gaskets
- Cam adjuster gaskets
I bolted everything back together yesterday and fired her up. Much to my dismay, the driver's side camshaft sprocket is rotating with a very visible wobble. Passenger side appears to be fine. The problem is that I'm not sure if this was an existing issue or if I caused the problem. I can't think of anything I could have done to cause it. I did not remove the cams or timing belt to do the service. I DID loosen the cam bolts on the passenger side to help lift the tensioner, but I didn't do this on the driver side. Worth noting that the driver side tensioner did not immediately spring back up after removing the 3366 compression tool. Others have noted this and that the oil pressure will most likely extend it. I still don't believe this could cause the wobble, but I'm not sure. I'm also noticing the "tin marbles" chatter from both heads now... and I've let the motor idle for about 3 min.
Any help on the issue would be welcomed (theres not much existing info on camshaft wobble). Figured I'd ask AW before risking a drive to the shop. THANKS!
07-10-2006, 09:33 AM
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Re: I dunno. Did you pry on it in any way?
Car has 75k... Timing Belt was done at 58k.
I didnt touch the cam sprocket or shaft or timing belt... I did take off the acc. belt tensioner and install a new one. I attempted to take the fan off but couldn't hold it to loosen the bolt. I rotated the bolt a few times uselessly.
I didnt touch the cam sprocket or shaft or timing belt... I did take off the acc. belt tensioner and install a new one. I attempted to take the fan off but couldn't hold it to loosen the bolt. I rotated the bolt a few times uselessly.
07-10-2006, 10:06 AM
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Re: OK, define wobble.
Off center... the sprocket bolt and plate (with the two alignment holes in it) do not spin evenly on the center axis of the bolt... Nothing really moves in and out. If you look directly down on it, it's moving side ot side as it spins.
07-10-2006, 10:33 AM
#7
The sprocket sits on a cone shaped mount, it's not keyed. The diamond shaped thing...
where you attach the alignment bar, is keyed, there is no way that can have play if the bolt is tight. Who did your timing belt?
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07-10-2006, 10:35 AM
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Re: Weird. How much does it move?
With engine off, I definitely can't force movement with my hand at all... If I were to make a guess about the lateral movement... it probably moves about 15-20% of the bolt width to both sides when rotating. Thats a complete guesss, but it is VERY noticeable, particularly compared to the other cam sprocket which is spinning perfectly on its axis. It looks like its shaking.
By the way, thanks for all your help Unpimp!
By the way, thanks for all your help Unpimp!
07-10-2006, 10:41 AM
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Re: The sprocket sits on a cone shaped mount, it's not keyed. The diamond shaped thing...
Kris,
I'm not sure what "keyed" means. The diamond piece certainly isn't loose, but it and the center bolt rotate together, off-center when engine is on. Granted, I haven't yet checked the bolt torque and I will do that first thing after work.
The TB was done by previous owner at a local, and reputable, European shop... "European Auto Works" for those of you in Nor*Cal.
I'm not sure what "keyed" means. The diamond piece certainly isn't loose, but it and the center bolt rotate together, off-center when engine is on. Granted, I haven't yet checked the bolt torque and I will do that first thing after work.
The TB was done by previous owner at a local, and reputable, European shop... "European Auto Works" for those of you in Nor*Cal.
07-10-2006, 10:50 AM
#10
So you are saying that the bolt and diamond move in an eccentric cirlce?
This is when viewed from the front?
Keyed means that on the end of the cam shaft, there is a cutout, in which sits a metal Woodruff key, which holds the (in this case) diamond shaped plate in a specific location, as this plate also has a cutout for the key.
Unless the end of hte cam is bent, or it's not sitting correctly in the bearings in the head, it's nearly impossible for it to wobble.
Keyed means that on the end of the cam shaft, there is a cutout, in which sits a metal Woodruff key, which holds the (in this case) diamond shaped plate in a specific location, as this plate also has a cutout for the key.
Unless the end of hte cam is bent, or it's not sitting correctly in the bearings in the head, it's nearly impossible for it to wobble.