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timing belt failure
#41

Having just had all the belts done before the Paso trip, I talked to the people who do work for me about what happened this past weekend.

The belts just installed in my car are Conti. I asked whether he uses Gates and I was told that the Gates belts are less flexible than the Conti and he felt that the reduced flexability could be a contributing factor to a catastrophic belt failure. He was absolutely certain about one thing, the same thing that flash just mentioned and that is you need to monitor belt tension and you need to do a shroud off inspection every 15,000 miles or so.

He also said that he has noticed that belts tend to wear and deteriorate faster in cars that are used frequently on relatively short trips. He cited my own car as an example. I've had 2 balance shaft belt failures with less than 30,000 miles on the belts and shown enough wear on the timing belt to require replacement at 30,000 miles or less. So at least with my car we inspect regularly and I plan for replacement every 30,000 miles.
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#42

I just replaced my belts a couple months aago, but I will do a retension ASAP after reading these horror stories on here. I learned what the inside of a 944 engine looked like after a break...
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#43

<!--quoteo(post=72251:date=May 19 2009, 07:52 PM:name=flash)-->QUOTE (flash @ May 19 2009, 07:52 PM) <{POST_SNAPBACK}><!--quotec-->on page 6 of the maintenance book that came with the car, it says the balance shaft belt needs to be inspected, and if necessary tightened EVERY 15,000 MILES
i'm willing to bet that almost nobody here does that<!--QuoteEnd--><!--QuoteEEnd-->

and I bet you're right, but I can tell you of at least one person [img]style_emoticons/<#EMO_DIR#>/rolleyes.gif[/img] that will start that practice from now on..
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#44

I think we can all use this unfortunate mishap as a wakeup call. It's worth re-iterating what Pete said about accelerating some of the maintenance items on our cars, and admittedly, I was unaware of the 15000 mile belt check Flash mentioned. Thanks for that one.

I've had to remove and install both belts several times recently (I still need to post that story) and I can tell you that the procedure is not that difficult at all. With the Haynes manual and 968 manual in hand and some help from Clarks Garage and of course this forum, I was able to figure it out fairly easily. First time took a little while but the second and third time became a breeze. And of course, checking the belts is a snap. No reason not to do that.
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#45

Just found a minute to peruse the forums and saw this. SUCKS Dan! Let us know how it goes.

Ron
94 coupe/6 speed
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#46

i have been told that the reason the conti balance shaft belts are not as good is because they are flexible - this is due to the higher portion of polyurethane in them - this heats up and then stretches - this allows the belt to come loose, jump, get tangled, and wreak havoc

kevlar, being more rigid, is a better solution
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94 Midnight Metallic Blue Cab Porsche 968 w/deviating cashmere/black interior and WAY too many mods to list - thanks to eric for creating www.968forums.com



"It isn't nearly as expensive to do it right as it is to do it wrong."
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#47

<!--quoteo(post=72285:date=May 20 2009, 12:01 PM:name=midblu)-->QUOTE (midblu @ May 20 2009, 12:01 PM) <{POST_SNAPBACK}><!--quotec-->Just found a minute to peruse the forums and saw this. SUCKS Dan! Let us know how it goes.
Ron
94 coupe/6 speed<!--QuoteEnd--><!--QuoteEEnd-->


Thx Ron, so can I borrow your car in the meantime ? I need to test drive a midnight blue coupe
to make sure that my pursuit of a second 968 in that color is the right decision [img]style_emoticons/<#EMO_DIR#>/wink.gif[/img]

Just drive up here, fly back and I'll bring it down to LA when mine is repaired [img]style_emoticons/<#EMO_DIR#>/tongue.gif[/img]
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#48

As luck would have it I am heading up your way for the weekend. Not sure you want my beat up old car but anything to help out!

Ron
94 coupe/6 speed
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#49

<!--quoteo(post=72296:date=May 20 2009, 03:27 PM:name=midblu)-->QUOTE (midblu @ May 20 2009, 03:27 PM) <{POST_SNAPBACK}><!--quotec-->As luck would have it I am heading up your way for the weekend. Not sure you want my beat up old car but anything to help out!

Ron
94 coupe/6 speed<!--QuoteEnd--><!--QuoteEEnd-->
Seriously?? Ron will you have the 968 with you or any spare time? If so then let's all meet up, afterall it's only been about 5 years! [img]style_emoticons/<#EMO_DIR#>/smile.gif[/img]
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#50

hell yeah, make some time for a beer or two ! [img]style_emoticons/<#EMO_DIR#>/smile.gif[/img]
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#51

Made an appointment with my mechanic. He installs only Conti and says that, in his experience, most timing belt failures are caused by overtightening. He said he's installed Conti for 25 years and, to his knowledge, has not had one fail that he installed. Obviously this is only one person's opinion but he has worked on many 968s. All of our speculation is purely anecdotal as each belt installed has different tension and the car will be used in different driving situations. Not trying to put anyone's beliefs down, but this is the opinion of one Porsche expert and if mine fails I'll have him fix the mess he created!
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#52

well, i have to disagree on this one - there are a ton of reports on this

i think your mechanic might possibly be otherwise motivated - try supplying your own belts, regardless of what brand you choose, and see how he reacts - if he balks, i would presume he was making a good markup on the conti, and that is where the recommendation came from

i won't put a conti in my car - way too much out there to indicate inferior quality and higher failure rate to risk it - conti is a softer material - that is a problem - i run the car too hard - the constant abrupt up and down of revs makes for some real tension on the belt - a soft belt is the last thing i want in there

dayco and gates are original (i'll dig up which was which) - i have always chosen gates for all my cars because they are just plain better than the rest

loose belts are what cause the problem, not tight ones (obviously way too tight could cause problems too) - this one is pretty easy to document - if you kept it a bit snug, it would not have a chance to get loose and get tangled - remember, mine did not break - it slipped up over the guide ring and sliced down the middle - it was also not too tight - the last time i checked it i thought about tightening it, but it was "ok" and i figured i would get to it when i changed the belts after getting back from paso - just never got the chance

next time you're inside there, fire up the engine with the front cover off, rev it up and let it down and watch the belt - you'll be right in there tightening it up - horrible design with way too much slop
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94 Midnight Metallic Blue Cab Porsche 968 w/deviating cashmere/black interior and WAY too many mods to list - thanks to eric for creating www.968forums.com



"It isn't nearly as expensive to do it right as it is to do it wrong."
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#53

As I said, I meant no offense but your opinion is is the EXACT opposite of what my Porsche trained tech said and he's been fixing and racing Porsches a lot longer than any of us. I could be wrong but I believe my mechanic said today that Conti is what Porsche supplies now. I can double check on that to be sure I'm not wrong.

Like I said, all evidence reported on here is anecdotal as I've yet to see any scientific evidence contrary to that fact. Has anyone stress tested both belts against each other? Furthermore, to intimate that my mechanic has any agenda is a bit presumptuous. Overtightening a belt can stress it and cause failure as much as undertensioning or loosening with heating. These were his EXACT words. Perhaps your belt and others were not installed correctly or inspected properly. As I said, I was not intending to offend anyone on here just give everyone the benefit of the opinion of an experienced mechanic. Ultimately it is everyone's individual choice and clearly these belts are a weak link, regardless of the manufacturer. I just hope no one else has to go through the experience you and Dan did.
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#54

since I am convinced that driving in 105+ degree heat with belts which were already more than 5 years old ( and then subjected to a 50 degree drop in temps for 8 hours, and then back to 100+ degree heat the next day ) had to loosen mine enough to factor in this disaster , with summer coming on and regardless if you mechanic may have overtightened them or left them a bit loose, or they're just right.. if the belts are more than 3 years old open that thing up and CHECK them !!!
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#55

no offense taken

i realize that my opinion is opposite that of your mechanic - there are countless mechanics out there who agree with me though, and yours is one of a very few i've heard of who prefers conti for any other reason than price

i know conti has incentive pricing, and i still suggest you test that theory - i said "might possibly" - it is a theory and nothing more - it is also very common practice amongst shops, so i would not be surprised - it is by no means a derogatory comment regarding your mechanic

conti may well be what porsche supplies now - that does not mean it is the best belt - it only means that it met the MINIMUM specs to become an approved vendor - porsche, like ALL auto manufacturers, chooses their vendors based on a number of criteria, including price - vendors change over the years, and not usually for reasons of quality

again i refer to the very controversial moog vs trw case

until recently, conti was about the least expensive belt you could get - this is why i think a lot of people defend it - again though, do a search here and elsewhere - you will find that the overwhelming number of failures are conti

as for scientific evidence, a recent conversation regarding composition, with someone who is in the business to know, leads me to thing that there is some out there - i will see what i can do about getting it posted

there is also a post here from somebody who knows about the original belts - do a search here an you can find it

the bottom line is that we all want to get to the bottom of this, and not have our belts fail, or have to tighten them every 6 months - i will pursue this further to get the ultimate determination
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94 Midnight Metallic Blue Cab Porsche 968 w/deviating cashmere/black interior and WAY too many mods to list - thanks to eric for creating www.968forums.com



"It isn't nearly as expensive to do it right as it is to do it wrong."
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#56

Off topic, but only slightly so [img]style_emoticons/<#EMO_DIR#>/unsure.gif[/img]

In what now feels like another ironic twist to these type of catastrophic incidents, I'm reminded of an idea which I introduced ( I'd prefer to say I "pioneered" it, but since it got nowhere I'll leave it at "introduced" [img]style_emoticons/<#EMO_DIR#>/rolleyes.gif[/img] ) many, many years ago on our good ole' ".net " forum . IIRC there were only about 4 or 5 replies to my post, some suggesting it could be worth exploring as a concept, although at a practical level it might be tough to develop a criteria, agree on parameters, establish a control mechanism, and then find someone to administer the process, etc . but I digress :

At the time I was proposing that in the event of a catastrophic mechanical failure suffered by a forum member, such as a timing belt break resulting in a $ 5k + nightmare, or a cracked block, cylinder head, maybe even pinion bearing, or a similar disaster ( I'm not talking about water pumps, power steering racks, main seal oil leaks and other more common, albeit expensive problems in their own respect ..) that we designate a forum administrator to be the recepient of whatever contributions other members may want to make to help out one of our own ( needless to say, ON AN ANONYMOUS BASIS ) and provide whatever financial relief those contributions may aggregately come to..

The administator would collect the $20, $50, or whatever amounts each member decides to send in and then generates a check to the car's owner. The idea was triggered by reading a few days before about another member's timing belt break and the bill he was facing, was unemployed at the time, just had a baby - you know, the perfect storm meets murphy's law [img]style_emoticons/<#EMO_DIR#>/dry.gif[/img] . I had gotten a nice bonus from work around that timeframe so I felt kind of guilty of my good fortune while another 968 owner was in a crisis and I thought .. we're such a unique, relatively small group, yet what if we manage to get 100 members to send in $50 each.. ? What the heck is $50 to us individually ( some of us spent that much weekly on cashmere socks [img]style_emoticons/<#EMO_DIR#>/tongue.gif[/img] , or on something really useless ), but imagine what the resulting $5,000 can do to this guy, lifting a ton of weight off his shoulders..

As mentioned above, I wasn't proposing this system is enacted to help anyone with expensive repairs of the more common variety... simply the rare, catastrophic level mechanical failures ( no accidents where the cars' body gets demolished, everyone should have insurance for that ).

Thinking these may happen only once in a blue moon to any given handful of members, and assuming that many of us would probably be comfortable enough with contributing a little here and a little there for what may only be a once or twice a year occurrence, I felt this was worth pursuing. Evidently, I was one of only four or five out of hundreds who thought that .. However, I can also see the arguments on the other side of the coin : the word gets around of how benevolent the goup may have been with one individual but then perhaps not so much with the next one, so it could make for some bad feelings among members and taint the whole thing by the realization that some of us may like one member more than another or at least it would highlight that point.. Also, the resentment that may come from some members who would argue this is simply a forum and not a "charity". My take on that is - no one is forcing anyone to send anything in, and no one knows who contributed and who hasn't, so where's the real downside ?

So I thought in spite of all the cons, I felt this was a concept which might work given the right parameters, criteria, rules and logistics that would have to come into play of course.. The question to me was always " why not ? ". But that concept died a quick and painless death, after a handful of posts, so I now after years gone by, and only reminded again by these recent events and discussions I thought it may be wothwhile revisiting this topic and see if at the very least it deserves a debate - shouldn' t we as a group look into something along these lines for the future to help those if and when we can ?

Or is this idea so far fetched that I should have my head exmined ? [img]style_emoticons/<#EMO_DIR#>/dry.gif[/img]
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#57

I can confirm that Contitech is the brand used by Porsche. I had my belts done by the Porsche Main Dealer about 8 months ago. Since I am busy replacing my clutch I can see the contitech logo comming past when I turn the crank.
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#58

<!--quoteo(post=72340:date=May 21 2009, 02:00 PM:name=ds968)-->QUOTE (ds968 @ May 21 2009, 02:00 PM) <{POST_SNAPBACK}><!--quotec-->Or is this idea so far fetched that I should have my head exmined ? [img]style_emoticons/<#EMO_DIR#>/dry.gif[/img]<!--QuoteEnd--><!--QuoteEEnd-->

Irregardless of the fact that you should have your head examined ( [img]style_emoticons/<#EMO_DIR#>/tongue.gif[/img] ), I'd be willing to participate in this provided some agreed upon structure is generated and adhered to.... I think it is a great idea and I for one would certainly appreciate it if I ever found myself in such a situation.

So count me in if you can generate a discussion and forge ahead. Perhaps a new sticky thread is in order? Maybe generate a "968Forums Catastrophy Fund?"

I think it will be an incredible uphill battle due to human nature, but it is a starting point for a great discussion nonetheless.

EDIT- I'd also suggest a fixed amount for such a donation- you don't want someone questioning whether or not others were as generous as they themselves were... I think $20-$25 would be an excellent, suitable amount. Even if only to help offset the total cost of repair... JMHO.
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#59

I would be willing to support a disaster recovery fund...you never know how's next [img]style_emoticons/<#EMO_DIR#>/ohmy.gif[/img]
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#60

the website cannot participate in such an arrangement - essentially it constitutes an insurance fund, which is carefully governed by law - also, we do not want to be in the position of being the one to make the decision of who receives the benefits paid out from that fund

but, if somebody wants to undertake this on their own, we have no issue with a thread to that effect being pinned here - we merely cannot participate in the fund beyond that
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94 Midnight Metallic Blue Cab Porsche 968 w/deviating cashmere/black interior and WAY too many mods to list - thanks to eric for creating www.968forums.com



"It isn't nearly as expensive to do it right as it is to do it wrong."
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