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Any experiences of Cam belt failure?

4241 Views 12 Replies 7 Participants Last post by  Malcqv
As a potential Ferrari owner you get it drummed into you that you must check cam belts have been replaced every 3 years and when you buy one, you must change them every 3 years max, if you don't your pistons are going to end up embedded on the underside of your hood (bonnet).

About 15 years ago, my car was at the workshop for a service so I borrowed one of my company's pool cars, a 1991 GM Vauxhall/Opel Cavalier 1.6 LS. It was about 2 years old and had done approx 50K miles. 5 miles into the journey, it made a strange noise and came to a shuddering halt. I was towed back to the local GM dealer, who promptly repaired the car, stating that the cam belt had gone, but it hadn't caused any damage to the engine and it was going to cost about £100. They also said that GM (Vauxhall/opel) had designed their engines so that in the event of cambelt failure no other damage would be caused.

My first question is this, if GM plus other manufacturers can manage this, why can't Ferrari?

My second question - Are the stories about Ferrari's eating cambelts just a myth, and does anyone have any real experience of cam belt failure on their Ferrari?

Having said that, I don't intend to use my 328 as a guinea pig for cam belt life expectancy, it's due a major in 2009 and will have the belts changed.
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As I'm sure you will recall, that company pool car had less than stellar performance. One of the reasons for that is the engine design. Ferrari engines are "interference fit" meaning the valves open into the space recent vacated by the pistons and then close just in time for the pistons to miss them on the rebound. This wide opening and long duration allows the engine to breath better and is one of the reasons we get nearly 100 HP per Liter. If the same principals were applied to the Opal, it would have registered someplace near 160HP. Its a trade off that many other car manufacturers are just learning. In the quest for maximum performance and fuel efficiency, its the only way to go (assuming Petrol).

To echo what Lane said and add a few other thoughts, the race Ferrari is not a hopped up road car, it is a de-tuned race car. The engine is basically just an air pump that can convert the energy stored in gasoline into rotational motion (very efficiently). Every revolution each cylinder goes through 4 cycles: Suck, Squish, Bang, Blow. To get the most power out of an engine you need the intake valve to open as far as possible for as long as possible to get the maximum amount of air in. You then need to squich this into the smallest amount of space possible without the fuel spontaniously exploding, then after your controlled burning pushes the piston down as far as it will go, you need the exhaust valve to open up real far and long to expel those spent gases. There is also a overlap period in which the intake valve opens before the exhaust valve closes to allow the established intake air velocity on a high reving engine to help push out the exhaust gasses.

Now for performance, the '79 308 has a 3 liter V-8 engine and produces around 250 hp, now back in '79 for Chevy to make that kind of power they used a 5.7 liter engine. A much more robust engine that generated much more torque at lower rpms but still an engine almost twice the size and made out of cast iron so it weighed half again as much.

I think the service intervals for the Ferrari belts are very conservative because Ferrari wants their cars to be top performers at all times and because the consequences of failure are so high. My sister had a 4-cyl Oldsmobile Firenza of about the same vintage as your Vauxhall and as I recall GM recommended timing belt changes every 60,000 miles. I think hers let go at around 50k also. But like you said, it was only a couple hundred bucks to get it back on the road.
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Word of caution

Records indicate that the belt and tensioners were replaced on my 348 at 23000 miles. That was back in Feb 2002. Due to the 5 year frequency recommendation and the "new to me" nature of my car, I decided to get the major performed this winter. Mileage on the car is now 32000 miles and I want to make sure everything is right.

After removing the engine and inspecting the parts we found that the cam belt was intact and in relatively good condition, HOWEVER, one of the tensioners had a flat spot or 2 in its rotation. The seal from the bearing race was pulled back and was about to cause a bigger problem. I'll try to get you a picture. A mere 9000 miles...I don't know how much time was left but just the thought scares me.
Ciao tutti

One of my first true exotics was a 83 Porsche 944 I owned it for about a 3 years and did most of mechanical myself, not familiar with timing belts at that time.
My ex mechanic kept telling me about checking the timing belt because if it ever failed it was going to cost $10,000 for a new engine, well that scared the hell out of me but I didn't know what to really look for (young and stupid)
so years go by without any mishap then I started to notice little pieces of black rubber about an inch long falling out of the car from time to time and when I opened the cam belt housing I then realized that it was the teeth of the timing belt well about 1/3 of the teeth were missing. By this time I had a new mechanic and I asked him how much for a belt change I remember when he told that it was not very much but I was a student at the time so I had to wait to raise some funds, well 2 days later it happened. Funny thing the belt didn't break but the rest of the teeth spun right off, I assumed I would never drive my car again :( , but two weeks later and $800.00 I did the job myself and good as new. :thumbup:

The whole point to this is that I drove the hell out of that car put at least 50000 km and the belt was 10 yr old before I even noticed any belt fatigue but I did notice and if I would of known what signs to look for the incident never would of happened so my question is can you view the timing belt on the 308, 348, 355, 360 if so it will definitely show if it is in good condition or show fatigue one way or another and this would make you feel more at ease when yo drive it I not saying not to change it but todays modern belts can easily go over the 5 yr mark especially when most of you put less then 50,000 km over 10 years.
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I know what you mean, and the Cavalier 1.6 was an interference engine I am sure.

I know that if the belts went in my VW then it would be costly. Maybe engines are just more "interference" than they were. I have heard of problems now where the aux belt/s fail and jam the cam belt sprockets causing catastrophic engine failure too. Happened to a mate of mine on his Peugeot.
We have all heard of the horror stories of Ferrari cambelt failures and the 20-30k resulting bill from the engine rebuild. To date though, I have never met an owner who actually had this happen to them. The only person I have met who said he had a belt fail on him (on a F355) worked at a dealership.
I guess thats the point. These belts are not going to fail suddenly nor instantly. There will be plenty of indication that you are about to experience a major problem provided you are paying attention. loss of belt edges will result in funny smells, loss of teeth - funny noise, bearing failure - funny noise. Power loss should only be noticable if you jump a tooth (I.E. timing issue). Even with both the tensioners and belt in extremely bad condition, the car should remain operational for a short while. But I'm not going to take any chances, PERIOD.

Here's the tensioner and bearing I mentioned with 9000 miles on it.


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We have all heard of the horror stories of Ferrari cambelt failures and the 20-30k resulting bill from the engine rebuild. To date though, I have never met an owner who actually had this happen to them. The only person I have met who said he had a belt fail on him (on a F355) worked at a dealership.
This is my point, we have all heard the horror stories, but do any of us actually know of any genuine Ferrari cam belt failures?

Thanks Pete & Lane for the technical answers, it's always interesting to read replies from those who know what they are talking about. I'm just a suit who works in an office and has to trust his mechanic to tell the truth.

That reminds me, I need to put some of that 710 stuff in that thing with the teapot on it;)
those who know what they are talking about.
Wait a minute...lets not get carried away. Pete yes, Lane..not according to my wife.

It took me way to long to decifer the 710 comment
Busted Belts

As an automotive instructor at a community college, I have seen many broken timing belts, mostly on high mileage Japanese cars. Interestingly, most of those broke when the owner was trying to start the car. My best guess is that overnight, the belt developed a little slack in it, maybe because the engine rotated slightly backward when it was shut off. When the owner turned the key the next morning, the belt was shock loaded and broke off a couple of weak teeth, or the whole belt. And most of those had nasty oil leaks to degrade the belt. In many cases, that was the end of the car. -Steve
There is a guy on FCHAT with a 308 and it happened to him. The thread was about the rebuild. This would of been a year ago at least.
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