12 years old Belts....look! | Page 3 | FerrariChat

12 years old Belts....look!

Discussion in '308/328' started by 11506apollo, Mar 17, 2020.

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  1. johnk...

    johnk... F1 World Champ
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    Fake news. I pretty sure I've never said, "that no experts have actually seen a car with a broken timing belt." Show me the unedited post. And I have never claimed expert status, though I have seen a car with a broken belt. Just application of common sense, like the post I just made comparing a Miata to a 308. Not claiming anything. Just presented data, facts, and questioning the inability of Ferrari to design a timing system as robust as that of a Miata, if indeed they are "frequency failers".
     
  2. thorn

    thorn F1 Rookie
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    The Miata engine design is 15+ years newer than the 308. And the cam gears are different, for one thing.

    Nobody's debating what Ferrari should have or should not have designed, except you. And this whole comparison to a Miata engine is going off an entirely different direction than the matter in hand.
     
  3. moysiuan

    moysiuan F1 Rookie
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    Miata = non-interference clearance engine
    Ferrari = interference clearance engine
     
  4. GordonC

    GordonC F1 Rookie
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    Here you go, from your first post in this thread:

    There you go - you said it. Own up to it.

    Funny that you choose this particular comparison... I've owned a 1996 Miata since new, it's been supercharged for the last 14 years of the 24 I've owned it. I've also owned a 2000 Miata for 4 years, then a 1995 Miata for 9 years, concurrent to the 1996 ownership.

    First point - your "data" is wrong. Miatas regularly break timing belts if you push them to near or over 100K miles. The Miata timing belt is rated for 60K miles service life. For California regulatory purposes, Mazda changed the recommended change interval to 100K miles in California only, and on www.miata.net forums, over the past decades, there are plenty of reports of Miata timing belt failures in the 90K+ range. Sure, lots go over 100K, but there's enough breaking before then that it is risking being stranded to push 100K on a Miata timing belt. It's a non-interference engine, so not any more expensive to repair if it breaks, but they DO break. I can find you a thread from this month on the Miata.net forum where someone experienced a timing belt break.

    I don't know which Miata club you were a member of or how many were in that club, but in the bigger picture, Miata timing belts break pretty routinely when you get over 90K+ miles. That's the fact. I've been on miata.net forum for the entire 21 years it's existed, was a moderator for 8 years, and have followed this all regularly. It's not power that breaks them, it's mileage (and age). I changed my 96's timing belt at 10 years when I changed to the solid lifter 99+ head and installed the supercharger, and will be changing it again this year.

    As for poor engineering and design by Ferrari being responsible for the shorter lifespan of 308 timing belts - perhaps true, by modern standards. Does that change the fact that belts break when they're old? No. If you want to compare the 308 engine's timing belt life span, why not choose a contemporary engine? The FIAT 124 double overhead cam engine (introduced late 1960s) has a factory timing belt service life of 36,000 miles (60K km), AND 7 YEARS. Gates recommends replacing the early 124 belts at 25K miles, later 124s at 30K miles. On Fiat forums, their recommendations on timing belt life pretty much mirror the (majority) recommendations here - change it if you don't know how old it is or how many miles it has, otherwise change it every 30K miles or 5 YEARS. Sound familiar? The twin cam 124 engine is also an interference engine, with proportionally similar or worse damage if the belt lets go. Go do some research on Fiat forums to see how many have seen an aged timing belt break. We'll wait.

    Back to the engineering aspect - look at the timing belt path on a Miata, there are 3 key points to consider:
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    1. tooth profile - modern rounded pulley teeth, versus ancient trapezoidal teeth on the 308's pulleys and belts.
    2. tensioner reverse radius profile - note how the tensioners (1 fixed, 1 adjustable) on the Miata timing belt do not flex the belt in a reverse radius significantly. We'll compare to the 308 tensioner later.
    3. Radius of the bottom crank pulley, and that the timing belt crank pulley is directly mounted to the crankshaft.

    Now look at the 308 timing belts - I'll borrow the Nick's Forza Ferrari picture, because it's really pretty, and we'll talk about the NFF solution more also.

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    1. Notice that the Nick's Forza Ferrari adjustable timing belt system uses a rounded tooth profile - that's very significant in reducing the stress on the timing belt and extending it's life. From Nick's page for this system: https://www.nicksforzaferrari.net/adjustable-timing-belt-systems.html
    "Designed by Team member & engineer Scott McGehee the NFF Adjustable high performance timing belt system designed for 60,000 mile or 9 year change on a OEM block. The belts are actually designed for a 90,000 mile interval; the only possible future issue is the lower drive bearings or OEM seals could fail before that time is up, so we recommend a 60,000 mile change or 9 years"​
    Scott mentioned those pulleys here, in 2017 in this thread https://www.ferrarichat.com/forum/threads/nff-performance-parts.544081/#post-145190678 he wrote:
    "the pulleys Nick carries are of course the adjustable ones developed over a decade ago right here on F-chat, utilizing the curve linear toothed belts vs the older outdated trapezoidal ones. "​
    There is quite a bit of discussion here prior to 2009 when that NFF system was being developed, searches provide references. One common comment, though, is that modern timing belts are both thicker and wider than the first generation timing belts like the Ferrari and Fiat designs, AND use more modern tooth profiles that cause less stress on the belts.
    2. Notice how the Ferrari belt path around the tensioner causes significantly more reverse flex than the Miata timing belt pictured earlier? That extra reverse flex on the belt causes additional stress on the belt, and therefore reduced life span.
    3. The Ferrari bottom timing gears are not directly mounted on the crank, but are gear driven off the crank - and a small diameter, which causes more flex on the belt than the larger cam pulleys. That small diameter bottom pulley causes more stress on the belts than a larger crank pulley as used on more modern engines. Before you point out that the Miata's bottom pulley is pretty small in diameter also, I'll remind that for a modern timing belt implementation with a thicker, wider, rounded tooth belt, it actually doesn't have a really long service life at under 100K miles.
     
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  5. johnk...

    johnk... F1 World Champ
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    1) Not really as not much has changed since the first Miata in '89 and 2) a 360 engine would be of the same vintage as a Miata but shares the same belt paranoia as the 308 (and all belted Ferrari). I don't think you can justify comments like belts are like tires because rubber is rubber, and then dismiss other belt driven systems because they aren't Ferrari.
     
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  6. johnk...

    johnk... F1 World Champ
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    Ok, I'll concede that point. No excuses, but not want I intended.
     
  7. thorn

    thorn F1 Rookie
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    Other than my house, my Ferrari is the most valuable thing I've ever purchased. I change the belts myself, along with all the other maintenance. It's ... what, less than $100 in parts? I can't even remember, that's how cheap it is. I also have a fire extinguisher in my house (yep, used that) and several guns (so far, not needed.) It's about being proactive.

    Your car, your choices. But I'll not be convinced that Ferrari's recommended schedule is nonsense. It's $100 and a few hours... I'll stay with the recommendation.
     
  8. moysiuan

    moysiuan F1 Rookie
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  9. INTMD8

    INTMD8 F1 Veteran
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    Was there 300k on that ^ :D

    At least the 5VZ is non interference.
     
  10. ferrariowner

    ferrariowner Formula 3

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    Tensioner bearing fail.
     
  11. moysiuan

    moysiuan F1 Rookie
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    Yep, that was my point, its not typically the belt that fails, rather a bearing fails and so goes the belt. The debate would be better framed as to what is the most suitable tensioner bearing inspection/change interval.
     
  12. INTMD8

    INTMD8 F1 Veteran
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    That's the idler but yeah it fell apart
     
  13. Albert-LP

    Albert-LP F1 Veteran
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    #63 Albert-LP, Mar 20, 2020
    Last edited: Mar 20, 2020

    I answer here only because I want to escape (at least with my mind) at the Covid disaster that's going one here: it looks like the apocalypse is coming. Here Fiat 124 twin cam engine started to be on the market in 1966 with 1438 cm3 and was installed on the Fiat 124 Spider, one of the best looking car ever, with a belt moving the two camshafts. Then it was produced in 1.3 - 1.6 - 1.8 - 2.0 liters displacement too. In 1971 a belt equipped Fiat 128 engine, a mass production car, 1100 cm3: here in Italy we knows very well belts applications since many years. The Ferrari 308 engine (7 years younger) has been designed using Fiat data and knowledge too. I'm a mechanical engineer, so i want to tell what follows, then you will decide what to do.

    Ferrari told at first 2 years interval for belts replacing. This happend in 1973

    Then it was raises to 3 years (that is a 50% increase!!!), I think in 1976 or something like that: means they had no idea about their reliability at first.

    Gilles Villeneuve destroyed his 308 engine every six months and brakes every two weeks: words of who serviced that Canadian orange 308 GTS, whom I'm proud to be friend of.

    If a belt can last 3 years (Ferrari official data) with Gilles on it (Gilles engine never had a belt failure) at 8000 RPM on the motorways up to the end of gasoline, I bet it can last (no less than) ten years without any big stress like it happens on MOST vintage cars. This is not why I bet, because it's easy for a technician to suppose this: the only reason why it can break is a too big tension during its replacement, that would affect the belt lifetime as tension stays also when you don't use the car (but tension is ONLY A PART of the belt load: that's the "cold" load, there is another much and much bigger one at high RPM that generates high belt and bearings temperatures too)

    2020 belts are much better than 1973 belts (like tires…)

    308 belt bearings were well calculated: they move an 1.5 liter engine each. They work for ten years on the heavy duty small truck Fiat Ducato 2500 Diesel, a 2.5 liter engine (one belt).

    The 308 engine is very well designed and reliable: it's the most reliable Ferrari engine ever. The same are its belts. The only way to have a failure is apply too much tension during the replacement or doing some mistake: they have to be installed by anyone that knows very well what he is doing.

    Everyone that has some mechanical knowledge here in Italy (knowing the Fiat 124 -132 - Argenta - Croma - Beta - Thema story and Ferrari 308 story too) will tell you that changing belts every three years on a 308 is a waste of money and time. Which is the correct interval? Everyone has his thinking, that is not official: we saw that 8-10 years are enough to be safe.

    PS
    My mechanic says 7-8 years, and he wants to stay safe, of course
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  14. mike996

    mike996 F1 Veteran

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    This belt thing makes my hair hurt.
     
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  15. Dr Tommy Cosgrove

    Dr Tommy Cosgrove Three Time F1 World Champ
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    I personally know 2 broken 308 belts that ruined the engine. One was on a car owned by one of us here.
     
  16. Dr Tommy Cosgrove

    Dr Tommy Cosgrove Three Time F1 World Champ
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    And I broke one on a 1990 Ford Ranger pickup once...
     
  17. Lawrence Coppari

    Lawrence Coppari Formula 3

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    What kind of lubricant should I apply to my belts to extend their lives? 0W-20 or 10W-40? Synthetic or dinosaur?

    On the serious side, the block is aluminum. With temperature increase, aluminum expands more than any other common metal. Setting a new belt too tight is not conducive to belt longevity because it'll get tighter when the engine warms. That's why I would never reinstall a used belt. It'll have to go through its initial stretch again.
     
  18. johnk...

    johnk... F1 World Champ
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    Still going I see. Yep, I know one guy very well. Me! Bent 4 valves. BFD. Totally unrelated to belt age or mileage. Furthermore, it was a mechanical issue that could not have been foreseen. **** happens.
     
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  19. Nuvolari

    Nuvolari F1 Veteran
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    I don't doubt for a moment that there are 308's out there that have experienced belt failures. By the same token there are 308's out there that have experienced wheels breaking, suspension arms cracking, and brakes failing all will dire results. Really no different to any other car as all machines are subject to failures and most times these problems are tied to bad service or neglect. The reality is that these failures represent statistical anomalies and no real data point for concern.

    For a moment lets look at a service spectrum with real extremes. On one end is a full mechanical tear down and forensic inspection and replacement of most every part after every drive. Of course this is hypothetical and totally not possible but work with me here. On the other end is no service of any kind and driving parts to failure. Somewhere between these two points is a place where service is chosen to be carried out. The motivations vary from person to person but it appears as though un-founded fear and listing to what the factory told us has most people in the 3-5 year range for belt service and if you are comfortable with that then that's ok but the truth is that it is a mis-informed opinion.

    In my instance I choose to apply personal experience, coupled with an engineering background, coupled with the direct feedback of the belt and pulley manufacturers and engineers, coupled with real-world feedback from Ferrari mechanics. Zero fear and totally analytical even though I'm highly motivated to not want to stroke a check for a new engine. All of this results in a time frame of about 10 years which I still believe (again a well qualified belief) that there is a significant safety factor built in and that I'm far from the real structural life of the bearings and belts (always assuming proper care, use, and maintenance).

    Life is full of calculated risks and one person's comfort zone is another's panic. I sleep like a baby with 10 year belt changes and should a belt fail before then I'll put my big boy pants on and accept the consequences knowing that my decision was made it with the best information I had available.
     
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  20. Dr Tommy Cosgrove

    Dr Tommy Cosgrove Three Time F1 World Champ
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    Besides being an expert in rubber chemistry and cam belt life expectancy on 308's and Miatas, what else do you know everything about?
     
  21. johnk...

    johnk... F1 World Champ
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    #71 johnk..., Mar 20, 2020
    Last edited: Mar 20, 2020
    I had a flat tire on one of my Miata once. Not sure if it was the nail or the tire age.
    I had a flat tire on one of my Miata once. Not sure if it was the nail or the tire age. I'm pretty sure it was the nail. But I never claimed to be an expert. So just guessing. But the tires were pretty old.
     
  22. Dr Tommy Cosgrove

    Dr Tommy Cosgrove Three Time F1 World Champ
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    You are not supposed to drive over nails. Trust me on this.
     
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  23. miketuason

    miketuason F1 World Champ
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    Alberto, I can totally agree with you, my Lancia Scorpion 1.8 ltr sat for three year then when I got around to starting the engine again without changing the belt, I drove it for more than 80k miles more with that same timing belt that was installed two years before it was parked for three year. Then finally I change the belt which looks fine when I removed it and replaced it with the new extra wide 25mm wide belt, so I’m good for another 100 plus miles again:)
     
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  24. Albert-LP

    Albert-LP F1 Veteran
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    another man that experienced a belt failure was me. Not on a 308, but on a Rover (with a BMW diesel engine): the belt that failed lasted 34 km (21 miles) and three days after replacement. I was lucky that I heard some noise in the engine bay: I stopped the car and saw, with the engine idling, a piece of belt beating against the belt covers. Stopped the engine, called the shop that had changed the belt three days before: they apologized and sent a rescue truck: "please don't start the engine anymore", they asked me. They gave me back the car with another belt few days later: for free, of course.

    ciao
     
  25. offtheworkigo

    offtheworkigo Karting

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    Anybody have or no where I can find the protection covers # 117628 AND # 117627
     

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