check those chain tensioners
12-29-2003, 04:58 PM
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check those chain tensioners
guys and girls,
Lets just say that Sean had a bad weekend, he parked his car (944 S2) at the mall, went inside, did some shopping, came outside and tried to start he car, no start (turns over but nothings happening) so he gets the car towed home and we start to check some small things (sensors and so on) everything seems fine, pull the valve cover off and, oh no! the top pad from the tensioner had been eaten up buy the cam gear, the chain's broken and so is one of the lug's that the tensioner bolts too, we think that bent valve's will be a huge possibilty, so guy's check/replace your tensioner pad's if you havent allready done so. Sean's car had just turned over 115,000 miles, And yes he was going to check them in a few weeks.
We will post pics soon
Lets just say that Sean had a bad weekend, he parked his car (944 S2) at the mall, went inside, did some shopping, came outside and tried to start he car, no start (turns over but nothings happening) so he gets the car towed home and we start to check some small things (sensors and so on) everything seems fine, pull the valve cover off and, oh no! the top pad from the tensioner had been eaten up buy the cam gear, the chain's broken and so is one of the lug's that the tensioner bolts too, we think that bent valve's will be a huge possibilty, so guy's check/replace your tensioner pad's if you havent allready done so. Sean's car had just turned over 115,000 miles, And yes he was going to check them in a few weeks.
We will post pics soon
12-29-2003, 08:26 PM
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Scott, sorry to hear about your friend's problem. It is an unfortunate situation that all 16 valve owners have to deal with. Not sure which is a bigger problem, pinion bearing or chain tensioner.
Hopefully your friend incurred minimum damage. Please post some pics if possible.
Regards.
Raj
Hopefully your friend incurred minimum damage. Please post some pics if possible.
Regards.
Raj
12-29-2003, 11:27 PM
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It is sadly true. I walked out for doing Xmas shopping to start up what had been a perfectly running car (aside from some minor oil weepage). I put the key in the ignition and cranked but the car was dead.
After several days of troubleshooting, we pinned it down to a failure of the the plastic guide shoe on the timing chain tensioner. Worse yet, I was aware of this as a known reliability problem on the 16 valve motors and it was on the list for repair.
The chain tensioner has a plastic guide shoe on both the fixed (bottom) side and the adjusting (top) side. It was the top guide shoe that failed and it wound up lodged in between the intake cam gear and the chain, resulting in the chain failure. Unfortunately, this loaded the chain tensioner so much that the tensioner mounting lugs on the cylinder head fractured...
I had delayed this repair simply because I really didn't know just how easy it would have been. Two fuel lines and pop off the valve cover. No problem. Scott says he has seen replacement guide shoes at Zim's, and they may be available through Porsche channels.
It is really a simple repair and a total cost of probably $100-150 for the DIY. Since my head is damaged, it will have to come off for a major repair. Fortunately, we have a spare 968 core motor that we have the option to rebuild.
If I am lucky, I may only be out of commission for a month and $1000+. I guess the silver lining is that it will give me the chance to fix a couple of other things, like a leaking Leda rear shock (see Leda thread).
Bottom line, if your S/S2/968 has much over 100,000 miles OR 10 years of age, do not put off this crucial repair.
Best regards.
After several days of troubleshooting, we pinned it down to a failure of the the plastic guide shoe on the timing chain tensioner. Worse yet, I was aware of this as a known reliability problem on the 16 valve motors and it was on the list for repair.
The chain tensioner has a plastic guide shoe on both the fixed (bottom) side and the adjusting (top) side. It was the top guide shoe that failed and it wound up lodged in between the intake cam gear and the chain, resulting in the chain failure. Unfortunately, this loaded the chain tensioner so much that the tensioner mounting lugs on the cylinder head fractured...
I had delayed this repair simply because I really didn't know just how easy it would have been. Two fuel lines and pop off the valve cover. No problem. Scott says he has seen replacement guide shoes at Zim's, and they may be available through Porsche channels.
It is really a simple repair and a total cost of probably $100-150 for the DIY. Since my head is damaged, it will have to come off for a major repair. Fortunately, we have a spare 968 core motor that we have the option to rebuild.
If I am lucky, I may only be out of commission for a month and $1000+. I guess the silver lining is that it will give me the chance to fix a couple of other things, like a leaking Leda rear shock (see Leda thread).
Bottom line, if your S/S2/968 has much over 100,000 miles OR 10 years of age, do not put off this crucial repair.
Best regards.
12-30-2003, 06:04 AM
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Sean, I am sure you will be able to coup some of your losses by parting out the broken motor. Let me know if you have any luck finding the lower chain rail. I was able to locate the upper one at Zim's but the lower one is NLA.
Also, I know someone who modifies a 928S4 tensioner and adds a bridge to it to give it additional strength. I can post some pics if you like. This mod is required for turbo-charging and he prefers using the 928S4 tensioner on a S2 head, deeming the S2 tensioner having too much tension and hence causing the failed chains.
Let me know if I can help further.
Raj
Also, I know someone who modifies a 928S4 tensioner and adds a bridge to it to give it additional strength. I can post some pics if you like. This mod is required for turbo-charging and he prefers using the 928S4 tensioner on a S2 head, deeming the S2 tensioner having too much tension and hence causing the failed chains.
Let me know if I can help further.
Raj
12-30-2003, 11:06 AM
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Originally posted by 968TurboS
Also, I know someone who modifies a 928S4 tensioner and adds a bridge to it to give it additional strength. I can post some pics if you like. This mod is required for turbo-charging and he prefers using the 928S4 tensioner on a S2 head, deeming the S2 tensioner having too much tension and hence causing the failed chains.
Also, I know someone who modifies a 928S4 tensioner and adds a bridge to it to give it additional strength. I can post some pics if you like. This mod is required for turbo-charging and he prefers using the 928S4 tensioner on a S2 head, deeming the S2 tensioner having too much tension and hence causing the failed chains.
I have a new upper pad on my car and I have a spare pad. The previous owner of my car got them for around $3.00 each. I'll get the part # off of my spare tonight and post it for anyone who needs it.
12-30-2003, 11:35 AM
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Pete $3 each, wow! Do you know where he got them for that price. I am looking for upper and lower pad. If you could help me find them.
I will send you a PM with the info and you can contact him directly. They do the same mod on all PH turbo conversions as well.
I will send you a PM with the info and you can contact him directly. They do the same mod on all PH turbo conversions as well.
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12-30-2003, 01:17 PM
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He's a fellow Rennlister in Boulder, Colorado who posts under the screen name JFrahm. His name is Joel. If you send him a message he could tell you where he got them. It's only the upper nylon pad. I'm 99% sure the only way to get the lower pad is to buy the complete tensioner assembly.
