[PhilG968]

Just experienced premature timing belt failure. Heard ticking from under the hood before I shut the car off.

When I came out after, the car wouldn't start. Looks like the crank sheered the belt, according to mechanic. Don't know any more details at this time.

Has anyone ever survived a timing belt failure without having to do the heads?

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[94SilverCab]

No!



At 56,000 miles (me believing that this was a part of 60K service)



Needed head rebuilt including all new valves...+/- $5k



Just my experience...can't speak for others.



Sorry,



Jay

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[Sho968]

[quote name='94SilverCab' post='41371' date='Sep 18 2007, 11:56 AM']No!



Needed head rebuilt including all new valves...+/- $5k



Just my experience...can't speak for others.



Sorry,



Jay[/quote]



Sorry to hear.

I too had to go through head rebuild.

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[Anchorman]

For the "database" - what was the history of the failed timing belt: how long had it been on the car, and how many miles?



Sorry for the incident. It is likely that the inevitable effort at restarting the car caused valve damage.

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[PhilG968]

[quote name='Anchorman' post='41373' date='Sep 18 2007, 12:12 PM']For the "database" - what was the history of the failed timing belt: how long had it been on the car, and how many miles?



Sorry for the incident. It is likely that the inevitable effort at restarting the car caused valve damage.[/quote]



Porsche God must be happy, report is all cylinders show good compression, and engine running quietly. Feel I dodged a bullet, now buying a lottery ticket!

Belt had 45,000 kl or 27,000 miles +/- a few.

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[sasilverbullet]

So much for everyone laughing at my shop recommending only going 30,000 miles on a belt <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" />

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[PhilG968]

I won't be laughing!

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[Anchorman]

WOW - on two fronts. First, it's great that you have no head damage. That is incredibly good fortune. Second, 27k miles - I'm at about 30k miles now, wasn't planning a belt change for another - whatever, thinking about getting it done SOON!

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[94SilverCab]

You dodged a serious bullet!!! Bet you won't let it get that close again...



At only 3,000 miles per year now (since my belt incident), I am going with the 5 year plan and I will be replacing mine at 5 year/15,000 mile intervals and inspecting/retensioning every year.



RS barn has brought all of my maintenance up to date and we have a plan that keeps my car mechanically perfect, and with (hopefully) enough $$$ left over to implement a new mod or two every year.



Porsche's are the most fun when it runs perfectly every time you start it.



Regards,



Jay

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[Cloud9...68]

[quote name='PhilG968' post='41386' date='Sep 18 2007, 08:19 PM']Porsche God must be happy, report is all cylinders show good compression, and engine running quietly. Feel I dodged a bullet, now buying a lottery ticket!

Belt had 45,000 kl or 27,000 miles +/- a few.[/quote]



Wow, congratulations on your good fortune! Do you happen to know the age of your belt (e.g. when was it replaced, as opposed to the mileage)? Those of us how don't put a lot of miles on our cars need to replace them more frequently than the recommended (varied as they may be) mileage intervals, so this information would be very helpful.



Until recently, I was all but convinced this business of needing to replace the belt at the ridiculous frequencies quoted by many on this boad were a combination of urban legend/extreme paranoia/a scam by the mechanics, but obviously the danger is very real. I realize the timing belt/roller system on these cars dates back to the '70s, but this doesn't make the change frequency any less insane. I know there's a new, heavy duty variocam chain available - does anybody know of a similarly more robust set of rollers and belts for this car? Or is the design just so pathetic that we're all stuck with this absurdity?

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[Darth Vadar]

Stuck with the absurdity...



I have always preached 5 years or 15K miles, even way back on my 951's and 944S and S2's...



And a lot of folks (who didn't know a Porsche from a Potato) laughed and said, "Oh, how ridiculous!"



Part of the reason that 944 and 951 values have fallen like rocks... if you buy a used one for $5K, don't service the belts, and then ruin a head, the car most likely goes on the scrap heap... how sad...



But then, I remember when Pontiac tried to use a Fiber Timing Gear on the HiPo 400 ci (and 421 ci) engines, and they weren't pretty when they let loose at 5K rpm either! DA Pontiac engineers! Or maybe we should blame the Cost Accountants???

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[sasilverbullet]

My shop that's been in business since 61 doing Porsches says every 2 years or 30K replace the timing/balance belts.

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[PhilG968]

Don't know when the belt was last done, car was new to me this February. Shop I take it to seems to think it may have had higher mileage on it than they thought at first, closer to 70k, 42k miles.

I will be keeping a close look on it now. When I purchased the car they were adamant the belt did not need changing, as I was suggesting it. I think the previous owner didn't drive it a lot, I drive a lot, every day. I also like to drive hard and keep up the maintenance so you can drive hard. Guess my driving style turned out to be the difference for the belt.

Well, replaced everything while we were in there, to the tune of $1000, but ready to go now!

Good news to know if it fails and you're not driving, you may dodge a bullet! Thanks for your replies.

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[flash]

it's as much a factor of time as mileage, so that may explain it too



also, if the balance belt was not retensioned frequently enough or correctly, it can snap and take the timing belt with it



for a car not driven on the track, i would check the tension and condition once a year or every 10k, whichever comes first

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[Cloud9...68]

I know this is a discussion about the timing belt, but since Flash brought it up, I have a question about the balance belt. I replaced mine a little over a year ago (it was the incorrect narrow one, and had sheared off about 20 teeth), and after about an hour of very frustrating fiddling with the tightening bolt, I finally got it to where it whines slightly but noticeably when cold, but then quiets down after it's warmed up, which seems pretty much perfect. I assumed that with all the talk about the need to re-tension this belt, the whining when cold would gradually decrease, indicating that it's time to re-tension. However, the sound has never changed. Since I basically used the sound as the final determiner as to whether I got the tightness right, and it hasn't changed the way I expected, what's the best way to determine when it needs to be re-tensioned? I must admit I've been VERY reluctant to mess with that tensioning bolt, for fear I'll never get it right again. Thanks.

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[flash]

well, it sounds like it was probably tighter than you think - somebody correct me if i'm wrong, but i can't see that this is a real problem - there is so much flex in even a tight belt that i don't think it would wear anything out but the belt itself - i also don't think it is possible to tighten it to the point of significantly altering timing - so, i don't see the harm, as long as you can live with the noise, and check for wear as i indicated above

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[Cloud9...68]

Thanks for the input. It still feels plenty loose. The first time I set it, it whined loudly, even after warm, so I definitely had it too tight. Now, the sound pretty much goes away by the time I'm out of my neighborhood. It just surprises me that even after five DEs, it doesn't seem to have lost any tension. Oh, well, I'll keep an eye (actually more of an ear) on it for any change going forward.

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[Cloud9...68]

As I said in another post, I did a driving event yesterday that was hosted jointly by the local Ferrari and Porsche clubs at a local track, and got to talking with one of the Ferrari owners about maintenance on their cars. I asked him about timing belt change interval and cost, and he told me the recommendation is every five years (I guess most Ferrari's don't get driven enough for mileage to become a factor), and the parts alone for their current generation V8 run $3500. Suddenly, I don't feel quite so bad about having to shell out a few hundred bucks every five years or so for the rollers and belts on our cars...

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[ldeprat]

Glad it was uneventful in the end.



Anyone here replacing or retensioning the belts themselves with the arnnworx tools?



I recently bought a set.

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[PorscheDude]

I have the arnnworx tools. He has a good write up on his site if you need directions. The kirkit can be a little tricky the first time you use it.



I have used them for 3 belt changes now. With each belt change I get a little faster.





G[color="#999999"]O[/color] A[color="#cc0000"]L[/color][color="#999999"]O[/color][color="#000000"]N[/color][color="#ff0000"]S[/color]O!

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