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Replace Conti with Gates?

Old 02-06-2017, 02:57 PM
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Martin's928
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Default Replace Conti with Gates?

Hi all, put ia Conti timing belt 2 years ago in my '88 S4 so not due for a while. Since then I have become more aware of the potential problems with the Conti belt.

Should I be worried enough to go back in and replace with Gates or is it reasonable to wait until the next scheduled change?

Thoughts?
Old 02-06-2017, 03:30 PM
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karl ruiter
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The trouble I personally have had with conti belts is some initial stretching when new. After a while I think they settle down. I don't know, however, if temperature is a factor. If so it might depend on how many miles, rather than years the belt has been on there. If you have enough miles and time, just checking the tension adjustment might be good enough. Also, if you have a porkensioner on there you may be ok.
Old 02-06-2017, 04:08 PM
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FredR
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An interesting question and one I have often wondered about.

The general consensus is that the Continental belt is more "stretchy". We often hear about the consequences of belt failure but how often does it actually happen and why? I cannot remember ever reading of a Continental belt having failed but that means little. Mark Kibort swears by the Conti belt and I doubt anyone beats on his motor like Mark does and he told me he had never seen any of his belts look close to failure. On the other hand a belt that stretches a bit more will retard the cam timing a bit and that favours top end power so one wonders if such could be an advantage. One also wonders if the belt is a bit more stretchy whether that might help reduce cam sprocket wear.

I use the Gates belt because that is the popular choice . That the Conti belt is different is one thing but whether it is less of belt is another matter altogether. It will be interesting to see what inputs you get on this one. My two cents is that if the Conti belt were no good or likely to fail they would not be selling it but...?

Rgds

Fred
Old 02-06-2017, 04:25 PM
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ptuomov
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Porken, who (I'd venture a guess) has looked at very many belts, writes:

http://liftbars.com/docs/PKT-S_install.pdf

"Continental belts are thicker (2.56 mm) and install with less T/D extension than Gates (2.49 mm) but both will stretch to be about equal. The Gates Racing belt is thinnest (2.39 mm), has the largest initial T/D extension but stretches less, and takes longer to stretch."
While not an expert, I'd use any of the three belts mentioned above without any fears.
Old 02-06-2017, 04:33 PM
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davek9
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Unless that T Belt is causing your car issues, I would not loose any sleep over it being installed.

How does it look at idle through the vent's in the upper T-belt covers, does it track correctly or wobble all over the place and is it at the Edge of one or both Gears?

Dave K
Old 02-06-2017, 05:27 PM
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Martin's928
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Thanks for all the advise. I installed a Porkensioner at the last belt change also and have kept an eye on the belt to decrease my anxiety at making the change. It has continued to run true on the cam gears and still looks in as new condition.

Only thing I haven't checked is whether the Porkensioner is overextended due belt stretch. I'll check that and, if it's ok, decide about which belt to use at the next scheduled change.
Old 02-06-2017, 06:11 PM
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Mikebte
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I have not heard anything bad about the Conti belts. Maybe if you live in a really dry climate i would check it sooner. But as others have said, dont lose sleep on it.
Not to jake the thread, but my next belt is a Gates. I found it in my box of parts last night. Forgot I had it. Last belt was a Flennor, no issues with it. Not sure if Flennor is outsourced or they make it. Could be a Gates for all I know.


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Old 02-07-2017, 04:19 PM
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The early square tooth belt was Flennor which is a Gates company in Germany. I currently can't purchase them.
OEM of the early square tooth belt is now the German company Dayco.
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Old 02-07-2017, 06:03 PM
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karl ruiter
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I have had a conti belt stretch and skip teeth in the first few hundred miles with the stock tensioner. Fortunately it was on a US '82.
Old 02-08-2017, 12:06 AM
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waynestrutt
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I put 190,000 km on my original “Conti” belt. Had the waterpump not started seeping I would still be using it. Between 86 and 96 there was never a day I did not run it for 5 minutes or so above 120mph. It was driven fast and when the pump dripped I parked it since my business needed full attention. 3 years ago I pulled it apart and was amazed at the amount of belt fibers and grease that filled the belt enclosure. That belt installed at the factory in 1980 never failed.

1980 928 metallic red
Old 02-08-2017, 12:10 AM
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Old 05-31-2019, 06:50 AM
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I am in the process of changing the timing belt on the blue car. Last time it was changed together with the water pump was in 1997 before my time and the car has been driven appr. 30K miles since that. The old factory belt, the factory water pump and everything else looks like new. In stock I have a number of Gates racing belts which I do not want to use for this engine. For this engine I have a Conti and a Dayco belt available. The question is which one to install.The Dayco belt do not have fully rounded teeth (pictures). The factory water pump with a plastic impeller looks and feels like new. I understand why people do change the water pump at the same time as it is hard to get to but the pump should last much longer than 30K. My experience from other engines is that the pump will last many times longer. I have never seen the water pump seep on any of the three cars I have. Any inputs?
Åke

Old 05-31-2019, 07:57 AM
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Forgot to say when checking the tension of the old belt before removing, the tension was found to be 5,2 (cold engine). The right tension is 4,5 so it looks like the tension has been slightly too high all the time since the last timing belt change. I have the Porsche 9201 special tool for checking the tension.
Åke
Old 05-31-2019, 08:29 AM
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Originally Posted by waynestrutt
I put 190,000 km on my original “Conti” belt. Had the waterpump not started seeping I would still be using it. Between 86 and 96 there was never a day I did not run it for 5 minutes or so above 120mph. It was driven fast and when the pump dripped I parked it since my business needed full attention. 3 years ago I pulled it apart and was amazed at the amount of belt fibers and grease that filled the belt enclosure.
Off topic, but Wayne, did you seriously leave the car sit from 1996 to 2014?? Wow, any ideas how the heads were after that?

Originally Posted by Strosek Ultra
The factory water pump with a plastic impeller looks and feels like new. I understand why people do change the water pump at the same time as it is hard to get to but the pump should last much longer than 30K. My experience from other engines is that the pump will last many times longer. I have never seen the water pump seep on any of the three cars I have. Any inputs?
Also off topic, Åke, the stories I have heard and have actually seen happen twice indicate that the sudden change on the loading on the water pump after it is has been used a long time and then suddenly gets a new re-tensioned belt could cause the pump to fail quickly. I have no idea what the mechanism is that could cause this. The two cases I have seen were both friends of mine, so I know that this happens. (But, maybe, in these cases, the new belts were just way overtightened?) Indeed, the factory pumps last a long time with the original belt. So, I understand how you draw your conclusion, but it seem like there could be other factors. Just the current status of my observations...
Old 05-31-2019, 10:06 AM
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Why not use the Gates "Long Life" belt?
Dayco (German) is the current supplier of the early square toothed belt to Porsche.
Are you sure that is not the early belt with the square tooth - what is the part number on the belt?

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