Cam Belt failures?

NOPE.

 

Objection your honor, statment is hear-say...

 

Me. On my 348. About 600 miles after the major service. Major in March 07. Failure in Sep 07.

The outer fences on my lower driven gear failed. As the bits of metal got sucked into the timing belt, it jammed the belt as it crossed the waterpump. 32 bent valves.


What exactly was your point? Major service has very little to do with timing belts. It's about all the other S^&T that can fail in these cars. Do you want to continue beating this dead horse about a 50,000mile published interval for the BB?

 

I do, not mine but a local (Atlanta).

 

I just paid over $7k for a major service (including all belts, tensioners, bearings, filters, fluids, etc, etc, etc,,,,,,)....................


Why would I do so??? So I won't find out IF cam belt failures happen due to not changing them, and/or how long you can go before they do, since that would be a VERY expensive experiment.

 

The interesting part of this thread is the cause of the belt failures. From the two examples given so far the failures have not been due to the belts, but have been from failures of other parts. I would not try to argue about Ferrari's 3 year, 30,000 mile interval, but would sure like to know what else we should be looking for. In your case would an inspection of the driven gear, or a more thorough inspection, have found a problem that would have prevented an expensive repair? A lot of people seem to look for the least expensive way to do a major service and feel pretty good that they put on new belts. Are they being penny wise and pound foolish if the person doing the service is not looking for the more common cause(s) of the belt failures? Are most belt failures the disease or just a symptom of other problems?

 

Tmobilguy (348), and Moretti (GT4??) in Australia.......

OTOH, I fired up a car that had been in the barn since Katrina, and drove it into Houston and the belts were 12 years old at the time of the hurricane, but it went straight into the shop, do not pass "Go", do NOT collect $200......

 

This doesn't exactly constitute a "belt failure", but my car at 89,000 miles had a failure of the cam drive bearing (not the tensioner bearing), but in effect would have the same effect on the valve train. Discovered during my rebuild and I would guess was within 1000 miles of completely shelling out, but luckily was still intact enough not to damage anything.

 

Granted, not Ferraris, but I have personally owned two (2) cars over the years (one SOHC, one DOHC) where there were neoprene cam belt failures. One happened to me, and one to the wife.

Both failed while the engine was warmed up, failing at idle after having run for 10 to 15 minutes (i.e., stopped at a traffic light).

Both failed due to the bottom crank shaft gear shearing off a couple of teeth on the belt. This bottom gear has the tightest radius, and therefore the fewest number of teeth engaged at any one time.

Both belts were original to the car, with (more or less) 10 years and 100,000 miles on them.

Both belts were coated with oil due to a leaky seal, which (my theory) weakened the neoprene over time. And I think this is the key issue.

Cheers - DM

 

I've only seen 2 actual timing belt failures. One was a Maserati BiTurbo that had around 15 years and 30K miles on the original belt. The customer dropped the car off in the morning (for belt replacement). At the end of the day one of the guys went out to bring the car into the shop NO START, belt had broken. The other was my 1990 Chrysler minivan. 15 years and 168K miles, water pump siezed, belt broke.

In the first case there were a number of bent valves and the customer was never satisfied with the result even though the car got fixed and he only paid part of the cost.

The minivan 3.0 isn't an "interference" motor so a water pump, tensioner and belt later we're back on the road.

 

I know of a friend who knows of a guy who's father-in-law knew of a Ferrari mechanic who said he never saw a belt failure if properly maintained. Is that hear say.

 

No, that is privilidged communication. As in a confession to your priest.

 

I hear what you're saying, but it sounds like hearsay.

How can that be ?

Regards,

Stew

 

I would be the person who had the cam belt failure... 85 308 gts, with about 80k miles, belts were just at the 5 year mark, no oil leaks etc... teeth on the belts were rotted out... dry, and the cam gear just sheered the teeth one day when I was coming home from church... Walt helped me take it apart ( he did most of it ) and put it back together... so BELT FAILURES DO HAPPEN.

I would change them every 3-4 years as reccomended. or you can pay $7k to re do your heads and untold time and stress getting the whole thing fixed.

take if for me ... I would change the belts first.

 

I only know of one case on a 308 but that was back in about 85 or 86 here in town and the guy was just about 5 miles down the road from leaving the shop when it happened, so that one doesn't actually count here. (for those who are wondering it was the red/tan 82 308 GTSi that sat in that front yard on Montevallo forever - I mean YEARS. Some people around here would remember that car)

So my short answer is no. Not once in 27 years of involvement with these cars. I hear it enough, though. Kinda like UFO's and Bigfoot.


Interestingly last year about this very time, the timing belt broke on my Ford Ranger when I was driving it. The truck just stopped running and for the life of me I couldn't figure out why until the next day in the daylight. Thank god it had room for the valves at TDC. It's a 1990 model. I am the second owner and I can just about be 100% certain it was the original belt. I guess the take home message is don't go past 17 years on a Ford Ranger...

 

I forgot about you

I'm at 4 years next month. I'm changing them this spring. It will be my 3rd time in 10 years.

 

and I know where this thread is going. It's my opinion, and my three cars that back me up, that only a nitwit changes belts sooner then 5 years unless the engine is already out or there is a good reason.

 

Franklyn, unfortunately this thread is going to prove nothing, just like all the others that have started with the same premise of "only first hand knowledge, etc.". Justify to yourself what you like, but the manufacturer does what they do, to minimize the risk for themselves AND the customer. More miles and time raises your chances, there is no doubt about that. Where the line falls to "over kill" depends on the individual....but when the belt slips for YOU, then it makes a big difference. To each their own, but I really don't think you will change anyones opinion on what is a reasonable interval.

While I was on the FerrariList email list, there were several individuals that discussed their having a belt shear off teeth and cause damage to the valve train. As I recall, one 355, two 308's, two Mondials and one TR. I believe in all instances the change interval was beyond 5 years.

 

I've always believed a lot has to do with the way the car is driven and stored. I try not to let my 328 sit for more than a month even in winter and I keep the garage heated to at least 40 degrees F. I will inspect them at least once a year to keep an eye for cam seals leaking and I will probably go at least 5 to 7 years unless I see something funny. If I let the car sit I will probably change them sooner. I have other cars to beat on at the track so I don't drive the 328 hard.

 

Spirot, as noted above, Tmobileguy, and a fellow I knew down south had one go after 14K miles. In addition, I was given a tour of TRutlands back in 2001. I seen a huge pile of junk engines, maybe 100. It was said it represented about a years worth and that most were belt failures. Butch Hooper said he bought a lot of cars with blown belts, and the guys at Norwoods seen a lot of them, as have Dave Helms, Brian Crall, etc., etc..

As honest as many owners might appear to be, the odds are greatly against the majority. Maybe one in twenty of us are honest enough to talk about it, the rest will find a way to make it go away quietly. To those its happened to that were open enough to talk about it, in almost every single event it was beyond the recommended time or mileage limits, but some not by very far, and some actually under the limits. The point is, just because a few people admit it, at possibly 20:1 (maybe worse) we arent really getting a good picture. But adding the experiences of others who actually have done the work, or bought or sold cars it happened to, its more of an issue than many want to seriously admit. Twenty years ago it was rather common to see 308's in Hemmings Motor News with bad engines from a blown belt. I read of many. Ten years ago you could find them on eBay quite often. Today, probably because so few cars are left, and what are left are being better cared for, its not as common. But it is still occuring.

The better question is to ask if its a problem. Any failure anywhere in the system, is a failure of the entire belt drive assembly. Whether the belt itself failed, the tensioner, drive bearings, or a pulley that sheared a flange, its still ultimately a belt failure. The valves will still smash into the pistons regardless of which particular part fails. And, the Ferrari 308 is a bit unique, in that while all the cars that had belt drives in its era are all more or less gone off the planet, the next generation of cars had a much improved belt and belt design that is much more durable, that wasnt yet available when the 308 was new, and it makes the 308 look like it has a big problem. The truth is that 70's Hondas and other junk blew belts all the time, its just that everyone forgets they did, as well as forgets that most those engines were of lower performance and/or non interference engines. IOW, when the belt failed on a Honda it didnt wreck the motor. Plus the motors were a dime a dozen if you wrecked one. Back in the day the junk yards used to be full of cars that got salvaged with blown belts. Well, 308s got sold off that way a lot too, and people like TRutlands and Hooper were buying them up left and right.

Many of those cars were repaired, and resold without service records, or anything to ever witness thier history. Sometimes only after someone takes one apart do they see the truth. Dave Helms got a real surprise recently after taking a 308 motor apart. makes you wonder what else is running around out there.

 

To me a rubber belt is a rubber belt. I think it has to do with sitting and the effect that has on the tensioner bearings. But what do I know...