Is factory recommended cam belt replacement too soon

15k or 3 years too soon? Factory/dealer scam?Is that based on the car being tracked or hard driving? Normal cars, 90k but I did my Lexus at 110k, belt condition still looked great. Anyone replace their cam belt after recommended, if so how many miles?

 

Goodness, this horse must have 9 lives.

Opinions on this cover a wide spectrum. My 360 is technically due for a cam belt change in June. It’s been driven 1500 miles since the last one, most of those just puttering around town.

Needless to say, I’m not putting on a truck to ship it to Dallas any time soon.

 

Ok; I’ve only had my Ferraris for four years and been on here for similar; but can somebody pass me the popcorn please? Sweat and sour would be great; thanks!!!! Ohhh and as you are up, a beer to please.

 

I change my 328 belts every five or six years. The old belts look and feel perfect...no cracks or frays, teeth fully intact and the rubber is still soft and pliable.

I only drive my Ferrari a few hundred miles a year (I have five cars), so that has something to do with it.

I use Hill Engineering tensioner bearings and Dayco belts.

And, no, I don’t change the water pump until it makes noise or leaks.

Alan
N.J.

 

328 pump easy to change at anytime. 348, not so much..355 isn't a walk in the park either.

 

I change my belts like a change underwear. Every 3 weeks because I get nervous that the belt I just put on might have a defect from manufacturing..

If I had a 430 or later car I'd change the chain every year because it might stretch... or have a manufacturing defect..

This question has been beaten to death. OP should ask their mechanic or do a search on this site.

 

I’ve stuck to the five year recommendation on my 328. Three majors with belt changes done under my watch, with another one coming in a year or so.

Of course, I also drive the snot out of my cars.

 

Ive had my 328 for so long, that I cant even remember how many times my belts were changed, I think I had them done at 98,000 miles , about 2 years ago. along with the water pump and the bearings, I think ?? lol

Thank you,

 

Most Ferrari engines use a shim to adjust the valve lash that means the cam is sitting on top of the valve and pushes on the flat of a “cup” that is over the valve stem (adjusted with shims) only a layer of oil is between to not make friction it is this type of set up that makes the belt work harder then the ones in a everyday driving car most to all modern domestic engines use a roller rocker arm to lower friction and free up gas mileage but is not reliable extremely high RPMs which Ferrari engines run at
Having a solid connection between cam and valve increase the performance and uses less parts but the trade off is maintenance Ferrari engines are designed for racing and as we all know a race team rebuild a engine after every race and replace all wear parts after testing and tuning
So because of that certain items need to be watched on a regular basis to prevent major catastrophes in the engine


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Interesting about the cams. The last race I attended in Laguna Seca, I spoke to the Ferrari race team mechanic, on their 488 race car, they rebuild their engines at 10k

 

Yes a very good friend of mine his son is a engineer for Hondas indy race team (he hates being a mechanic lol) and says the same thing
Although he works for Honda all manufacturers for pretty much the same as far as their race operations go
The engines are so much more Advanced then what we have
he showed me that Honda uses veritable valve timing cams with a timing chain (no rubber belt) and the engine management system has more data inputs then a production vehicles
he can see live data on how many degrees of stretching of the timing chain is while in a race
Wild stuff remember most of what they find that works on the track will some day end up on the street



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I have long term owned three Ferraris since 1994. And although this topic has been beaten to death, this is the best explanation I have ever read.

Thank you!

 

Beat to death. 5 to 7 years depending on your confidence in who did the previous work.

 

Thanks my high school auto shop teacher was a factory train Ferrari tech before becoming a teacher and he was great he had us working on Ferrari’s all the time with a close eye of course
But again this was in the early 80’s well before electronica fuel injection and was mostly carbs and Bosch k-JeTronic good times for me



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Sorry, I can't agree with this theory (my background is mechanical engineering) - it's not just racing engines or exotic engines that use this valve actuation design, and this design in itself doesn't increase belt tension or loads compared to other valve actuation designs. Cam acting directly on a shim or bucket is pretty common - for example, Mazda has used that design for 30+ years on their double overhead cam 4 cylinders (Miata MX-5 engines, for one specific model to reference, the B6 and BP series 1.6 and 1.8 engines), in millions of cars, and their timing belts are rated for 60K to 100K change intervals. The cam lobe on shim isn't a high force interface - of far greater significance would be the cam profile, how steep the lift ramp is determining how quickly the valve is opened, and the valve spring rate. High spring rate valves have more force on the cam face - but again, there's lots of other engines out there with redlines in the 7K to 8K rpm range (same as 308/328, 348) so Ferrari didn't use valve spring rates significantly higher than other manufacturers with similar operating parameters that have much longer belt change intervals.

Ferrari didn't always recommend 3 year belt change intervals - originally, their change interval was 52,500 miles. The 3 year recommendation from Ferrari is relatively recent, with an explanation that it's for cars in the certification program to remain certified. Many owners of timing belt Ferraris have moved to 5 to 7 year change intervals, and even then the concern isn't so much belt wear or risk of breakage on age (since we know belts last longer than that), it's for inspection of the tensioner pulley bearings and to have a look at the timing belt drive pulleys and check for leakage.

Here's an article by Mike Sheehan from a few years ago, specifically about this issue and how the 3 years official recommendation came about. https://ferraris-online.com/serpentine-issue-straight-answer/ Gates, the belt manufacturer, recommends a 9 year change interval. Mike sums up with:

Here’s the bottom line on belt replacement. You’ve got the following choices.

1. Every nine years, as Gates recommends.
2. Every 52,500 miles, as Ferrari used to recommend for the 355 and earlier cars.
3. Every five years, as is the common recommendation today.
4. Every three years, as Ferrari has now decided needs to be done for a car to be “certified.”
5. Every three months, if you want to keep your mechanic busy.

Personally, I get by with an annual visual inspection of the cam belt and tensioners, and with a replacement every five to nine years, unless my car spends time at the track.​

I replaced the belts on my 308 in 2014, 1 year into my ownership, about 7 years after they'd last been changed. I just replaced the belts again in November 2020, 6 years later - a year earlier than I'd planned, but I was in there doing other work, and it was within the 5 - 7 year range that I plan to follow.

Cheers,
Gordon

 

I see your point but I check a 1999 Mazda with the specs you listed and Mazda said 48 months or 60k which is around 15k and Mazda engines are build with a balance of power , dependability and emissions with a much lower cost of ownership it’s not a everyday driver Per-say but they do get used a lot more and have completely different internal engine specs

Ferrari’s has used multi metal valves for most of the early engine production which I’m sure you have seen and heard of valve heads braking off and guides seizing etc this was all the way up to the 90’s even your 308” which I think is one of the best cars to own and drive” can have these issues if not caught by a competent mechanic doing a proper engine out service most cars up to the early 70’s still used lead gas and I remember in the 89’s shops pulling heads off to replace valves and guides Ferrari’s where no different at this time with your back round in engineering I’m shore you leaned about how metals dissipate heat and change diameters as well as needing certain types of lubricant to lower frictionwell that’s what leaded fuel did for the part of the valves on the combustion and exhaust side by the timeline you and the article was written most of not all manufacturers have been using proper materials for that problem and so did Ferrari
I have been looking for a 348 or 355 and one of the key points is the engine out valve services for a reason these cars share the same engine platform as the 308 and 328’s “which again I think are absolutely beautiful” so on these points and a few others I stand behind what I know and with a hefty price to pay if a belt brakes I will do my inspections and replace at a Comfort zone that I not anyone else’s feels is acceptable Image Unavailable, Please Login Image Unavailable, Please Login


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The screen shot you posted says to INSPECT at 48 months, not replace. I can guarantee you that the recommended replacement interval is 60K miles, except in California where the belts are required to last 100K miles and so that's the recommended change interval. Exact same belt, Mazda just extends the interval because they had to and it was the cheapest way to meet the California requirement. There are a few examples of Miata timing belts breaking around the 100K mark, but they never break at 60K miles, no matter the age.

Ferrari used hollow stem sodium cooled exhaust valves in the 2 valve per cylinder engines until 1982, then switched to solid stainless steel exhaust valves for the 4 valve per cylinder engines, including the quattrovalvole 308 engines in 1983. My 308 is a QV, solid exhaust valves, no breakage problems. A concern with extended timing belt changes has been the tensioner pulley bearings and the possibility of them seizing, which is why many of us have switched to an improved tensioner pulley bearing made by Hill Engineering, which will outlast the factory bearings significantly - again, extending the interval into the 5 - 7 year window.

Neither of those factors, however, have anything to do with cam on shim/bucket pressures which you stated to cause higher belt forces and wear them out sooner - that still is not a factor in Ferrari timing belt change intervals.

The lead in leaded fuel mostly was to prevent wear on valve seats and to provide anti-detonation characteristics - the use of different materials for valve seats, starting in the early 1970s, solved the lead removal problem immediately for valve seat wear; engines had to be tuned differently to account for the lower knock resistance of unleaded fuels.

Absolutely, every owner has to consider all information available to them and decide for themselves what belt change intervals they are comfortable with (but cam on shim or bucket valve actuation is not a factor on belt longevity).

Cheers,
Gordon

 

So at this point we have come to a “ quagmire” it’s probably safe to say we might find out what the “33” on a bottle of Rolling Rock Beer stands for before someone will agree on a belt services and why


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