Cracked cam gear???
08-02-2010, 01:55 PM
#31
Rennlist Member
I always use a rubber strap wrech to hold or rotate the cams when installing a timing belt.
From reading this the washers were put in post mortem to help with the investigation. They are not a cause.
From reading this the washers were put in post mortem to help with the investigation. They are not a cause.
08-02-2010, 04:22 PM
#32
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The cam is not necessarily bad. The keyway is roached out. However the keyway doesn’t locate the cam gear on the shaft. It could clean up with some emery paper. Certainly not the recommended procedure. But it could save the car from becoming a parts car or junked.
My bad. On the 16v engines the keyway does locate the cam gear. It is the 32v that relies on the clamping force of the cam retaining bolt to lock the timing of the cam gear to the cam. (that and the 3 tiny distributor rotor screws) I made this mistake because I had the 32v type cam adjusters on my old 16v 81. I put the 32v adjusters in because I milled the heads to raise the compression and installed early cams.
With that said, if you wanted to, you could time the cam and clamp it like a 32v. It should be as good as the factory does on a 32v. Though, if you can afford the parts and labor, replace it.
NF
08-02-2010, 08:59 PM
#33
Team Owner
Thread Starter
I use a 30 mm wrench on the washer behind the bolt to hold it in position to torque the 17mm bolt.
Fraggle correct the 3washers were installed post mortem just to make it easier to get the bolt tight to turn the cam over to investigate the damage
Fraggle correct the 3washers were installed post mortem just to make it easier to get the bolt tight to turn the cam over to investigate the damage
08-02-2010, 09:23 PM
#34
Rennlist Member
should be pretty easy to get that new cam pullley back on the shaft of the cam. using a method like the 32valvers use is a good idea too. vs taking the cam towers off??? no brainer. How hard can it be? whats the worse that can happen? it might move? and you have to do it all again. Hmmm. good point.
anyway, wild failure.
Best of luck!
mk
anyway, wild failure.
Best of luck!
mk
08-03-2010, 01:20 AM
#35
Rennlist
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Never turn anything with the 17mm. Always turn with the "nut washer".
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Semi-retired, as of Feb 1, 2023.
The days of free technical advice are over.
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greg brown
714 879 9072
GregBBRD@aol.com
Semi-retired, as of Feb 1, 2023.
The days of free technical advice are over.
Free consultations will no longer be available.
Will still be in the shop, isolated and exclusively working on project cars, developmental work and products, engines and transmissions.
Have fun with your 928's people!
08-03-2010, 01:24 AM
#36
Rennlist
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I'll put my money where yours is ......
gear started to loosen .... cam/gear interface wears more ... gear gets even looser .... keyway and key start to get a hammering from gear rotation .... rotation becomes so severe, and keyway/key so trashed, that key starts to roll ... key becomes a wedge that splits gear as it rolls
gear started to loosen .... cam/gear interface wears more ... gear gets even looser .... keyway and key start to get a hammering from gear rotation .... rotation becomes so severe, and keyway/key so trashed, that key starts to roll ... key becomes a wedge that splits gear as it rolls
08-03-2010, 07:52 AM
#37
Rennlist Member
OK, flame suit on. I JB welded the keyway on my 40 year old shop air compressor about 3 years ago and it has never given me a bit of trouble. It's always on, and gets a fair amount of use. Of course, different app, different stresses, but just wanted to throw it out there. In a non-interference engine it might be worth a shot.
08-03-2010, 04:13 PM
#38
Rennlist Member
OK, flame suit on. I JB welded the keyway on my 40 year old shop air compressor about 3 years ago and it has never given me a bit of trouble. It's always on, and gets a fair amount of use. Of course, different app, different stresses, but just wanted to throw it out there. In a non-interference engine it might be worth a shot.
Also, it is not uncommon to mill a new keyway 180 deg away into 'fresh meat' ... and similarly, tick a new index notch 180 deg out on the new cam gear: all will remain in correct time.
01-19-2013, 11:27 PM
#41
Team Owner
Thread Starter
sorry for a late answer to this BUT
Both cams were replaced,
both pulleys were replaced,
as well as both of the cam to pulley bolts,
and the tower gaskets, new belt fitted
and new water pump
belt tension was then set to the bottom of the kempf tool instead of the top as done on the S4
Both cams were replaced,
both pulleys were replaced,
as well as both of the cam to pulley bolts,
and the tower gaskets, new belt fitted
and new water pump
belt tension was then set to the bottom of the kempf tool instead of the top as done on the S4
