Lesson Learned - I need to check cam gears more frequently!
12-21-2009, 11:20 AM
#17
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Hello Karl,
The belt has the word "Contitech" on it - it's the only word I can make out on the belt. I assume this is a Continental belt?
Hi Davek9,
For that pic, the crank was NOT at TDC. When I brought the crank to TDC, the play between the cams was taken up and all the slack was at the TB tensioner between the crank gear and the passenger cam gear.
Hello Martin,
I'm going to check out the WP more closely today - good eye on the dampness below the WP pulley!
The belt has the word "Contitech" on it - it's the only word I can make out on the belt. I assume this is a Continental belt?
For that pic, the crank was NOT at TDC. When I brought the crank to TDC, the play between the cams was taken up and all the slack was at the TB tensioner between the crank gear and the passenger cam gear.
I'm going to check out the WP more closely today - good eye on the dampness below the WP pulley!
12-21-2009, 11:23 AM
#18
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That is pretty amazing ... good catch, glad you found it in time.
BTW, not to change the subject, but I just changed my flappy bearings and reassembled the mechanism using your excellent illustrations and guide. Sure is easy when there are such great resources to guide you along!
FWIW, I found a 3/8" threaded rod caught and pulled out one of the seal o-rings on the first bearing, so I tried a quarter-inch rod for the other bearing and recommend that. As long as you watch the alignment it will pull the bearing into place just as easily, and will not catch and pull on the seals as you work it in and out of the bearings.
Also, my flappy valve has an "up" arrow marking on the driver's side. I fiddled for a while getting the chamfer lined up correctly before seeing the arrow.
BTW, not to change the subject, but I just changed my flappy bearings and reassembled the mechanism using your excellent illustrations and guide. Sure is easy when there are such great resources to guide you along!
FWIW, I found a 3/8" threaded rod caught and pulled out one of the seal o-rings on the first bearing, so I tried a quarter-inch rod for the other bearing and recommend that. As long as you watch the alignment it will pull the bearing into place just as easily, and will not catch and pull on the seals as you work it in and out of the bearings.
Also, my flappy valve has an "up" arrow marking on the driver's side. I fiddled for a while getting the chamfer lined up correctly before seeing the arrow.
12-21-2009, 11:34 AM
#19
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That is pretty amazing ... good catch, glad you found it in time.
BTW, not to change the subject, but I just changed my flappy bearings and reassembled the mechanism using your excellent illustrations and guide. Sure is easy when there are such great resources to guide you along!
FWIW, I found a 3/8" threaded rod caught and pulled out one of the seal o-rings on the first bearing, so I tried a quarter-inch rod for the other bearing and recommend that. As long as you watch the alignment it will pull the bearing into place just as easily, and will not catch and pull on the seals as you work it in and out of the bearings.
Also, my flappy valve has an "up" arrow marking on the driver's side. I fiddled for a while getting the chamfer lined up correctly before seeing the arrow.
BTW, not to change the subject, but I just changed my flappy bearings and reassembled the mechanism using your excellent illustrations and guide. Sure is easy when there are such great resources to guide you along!
FWIW, I found a 3/8" threaded rod caught and pulled out one of the seal o-rings on the first bearing, so I tried a quarter-inch rod for the other bearing and recommend that. As long as you watch the alignment it will pull the bearing into place just as easily, and will not catch and pull on the seals as you work it in and out of the bearings.
Also, my flappy valve has an "up" arrow marking on the driver's side. I fiddled for a while getting the chamfer lined up correctly before seeing the arrow.
12-21-2009, 11:54 AM
#21
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Hello Michael,
This was on the '84, 16-valve engine so it doesn't have the Belt Tension warning system.
I kinda like the 16V engines as they seem to take a lot of abuse, are resilient and keep running. I'm gonna miss California when I swap him out for Oregon as my next DD.
This was on the '84, 16-valve engine so it doesn't have the Belt Tension warning system.
I kinda like the 16V engines as they seem to take a lot of abuse, are resilient and keep running. I'm gonna miss California when I swap him out for Oregon as my next DD.
12-21-2009, 12:19 PM
#23
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Guess I can't feel unique anymore 
https://rennlist.com/forums/6990975-post12.html
Mine was a case of overtightened belt and broken cam.
https://rennlist.com/forums/6990975-post12.html
Mine was a case of overtightened belt and broken cam.
12-21-2009, 02:30 PM
#24
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Dwayne
I have a couple of complete sets of the early style (square teeth) pullies that are in good shape and need a home. You are welcome to a set for the cost of the shipping from Honolulu. It is a bit of a downgrade for the car, but for a U.S. 16V motor it is just fine, and would save some $.
I have a couple of complete sets of the early style (square teeth) pullies that are in good shape and need a home. You are welcome to a set for the cost of the shipping from Honolulu. It is a bit of a downgrade for the car, but for a U.S. 16V motor it is just fine, and would save some $.
12-21-2009, 03:25 PM
#26
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Dwayne,
Be aware that the aluminum oil pump gears had been superceeded by steel replacements. You are probably going to have to replace the crank gear as well.... Only use Porsche belts.
A Porkensioner will make California feel all better again.
I was thinking "hmmm clear timing belt covers", then I read DanglerB's comment about it. Sure would be a practical mod. Injection molded TB covers would be ideal, but the tooling would kill us. Thermoformed covers could be done inexpensively though.... Maybe even just the portions that cover the cam gears would suffice. I wonder if Porsche could be persueded to run their tooling with some clear Nylon 12 or some polycarbonate? The nylon 12 would have the best chemical resistance... I wonder if the TB cover tooling still exists, or if it's in running condition...
Be aware that the aluminum oil pump gears had been superceeded by steel replacements. You are probably going to have to replace the crank gear as well.... Only use Porsche belts.
A Porkensioner will make California feel all better again.
I was thinking "hmmm clear timing belt covers", then I read DanglerB's comment about it. Sure would be a practical mod. Injection molded TB covers would be ideal, but the tooling would kill us. Thermoformed covers could be done inexpensively though.... Maybe even just the portions that cover the cam gears would suffice. I wonder if Porsche could be persueded to run their tooling with some clear Nylon 12 or some polycarbonate? The nylon 12 would have the best chemical resistance... I wonder if the TB cover tooling still exists, or if it's in running condition...
12-21-2009, 04:03 PM
#28
Race Car
Dan
'91 928GT S/C
475hp/460lb.ft
12-21-2009, 04:07 PM
#29
Former Sponsor
This entire cam gear thing is like dry rot in wood...once one piece has it...it spreads to everything else.
Any wear on any of the gears will transfer to the new belt and then that wear will spread to the new gears. Some people replace the cams gears and the oil pump gear and never look at the crank gear, because it is steel. Well, they wear too! Take a good look at that gear too. It is very common for us to replace all four gears, so this problem doesn't repeat itself in 25,000 miles.
Only use factory cam belts! That being said, Roger claims that the Gates belts he sells are exactly the same as a factory cam belt. He has done a ton of research on this subject and I'm pretty/absolutely certain he is correct. I still buy factory belts....it's a corner I just can't seem "to cut".
Any wear on any of the gears will transfer to the new belt and then that wear will spread to the new gears. Some people replace the cams gears and the oil pump gear and never look at the crank gear, because it is steel. Well, they wear too! Take a good look at that gear too. It is very common for us to replace all four gears, so this problem doesn't repeat itself in 25,000 miles.
Only use factory cam belts! That being said, Roger claims that the Gates belts he sells are exactly the same as a factory cam belt. He has done a ton of research on this subject and I'm pretty/absolutely certain he is correct. I still buy factory belts....it's a corner I just can't seem "to cut".
12-21-2009, 07:16 PM
#30
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I saw one once that the teeth wore down so the tops were completely worn away you could see through every one.....car still ran. And like this one a 16 valve none interference engine.