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Timing Belts ... The Kiss Of Death

Discussion in 'Ducati General Discussion' started by oldtech, Aug 1, 2020.

  1. I have owned my integrale evo 2 for 17 years.... from 2003 to 2008 i had the belts changed by Auto integrale every 2 years..
    Keith never advised water pump replacement although i did have it replaced when he completed a head rebuild and head gasket for me (had an oil leak from it) as i had noticed a small coolant drip from pump.
    I now do my own belt swaps as the modern integrale tax has pushed the belt change costs skywards.
    The water pump is not cambelt driven on the 8 or 16v engines.... so i have never seen the need to swap it every change.... Depending who you ask the interval in a 16v ranges from a year to 3 at the outside... John Walley told me if you leave it longer than 3 years your asking for trouble And to be fair at 18mm wide its a narrow belt.
    The 20v 5cylinder engine in the fiat coupe is supposed to come out at 72k for cam belt and tensioner .....i have done a few belt swaps on these as i have a couple of mates with them. On this engine the water pump is cam belt driven and the cam position sensor is buried behind the inlet cam sprocket so worth replacing both when its all apart.... you can change the belt in the coupe with engine in but you cant get the tensioner off its stud as it clashes with the chassis rail at the side of the engine bay.... but you can loosen the engine mounts.... and push the engine over far enough to get the tensioner in... this while not to the fiat book is a lot simpler than heaving an engine out!
    Getting back to the Ducati this is an interesting thread.... i changed my new to me 748 belts last christmas.... I'm expecting to replace them every couple of years although did strike me as a very short interval.... better safe than sorry i guess..... my last integrale belt only covered about 1500 miles in 3 years.... but i changed it anyway.... not worth the risk!
    Cheers
    Peter
     
    #81 Peter J748s, Sep 9, 2020
    Last edited: Sep 10, 2020
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  2. strange on a car,you can go 80k ,think we ducati owners have been brainwashed into spending lots of money and time on belts when perhaps they dont need doing,still that nagging feeling of snapped belts,aghhhhh
     
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  3. Car belts are often wider.... Ford zetec belt on my old puma 10 years or 100k... but its a wide belt... like the fiat coupe... the ducati is narower... and rads of the pulleys are small..... there is prob a bit of paranoia but for 100 quid every two years i will prob just do them...much cheaper than an engine!
    Cheers
    Peter
     
    • Agree Agree x 1
  4. Seems to me there's at least three factors in play here: as noted, car belts are often wider, they certainly don't normally operate at the rpm that a Ducati does, and they are not normally so 'distressed' by being bent both ways by the tensioner (not good from the fatigue POV, as any engineer will tell you). I would not care to exceed the recommended service intervals. That said, I firmly believe that 95% of belt failures are caused by poor initial fitment. And I speak as someone who has suffered a (very expensive) belt failure, which I put down to being in that 5%.
     
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  5. Good point on the RPM!
    The only timing belt so far that has failed on me was in my mums old Volvo 480... many years ago.... the funny looking coupe.... we had belt changed at the dealer....when we got it back i said.... that sounds tight.... its whining...service manager says... no no it fine... 10k later.... ping..... 8 bent valves...
     
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  6. Ouch!

    But I'll bet the valves weren't £120 +VAT each like the Ducati ones were!
     
  7.  
  8. No fortunately not.... as I recall it was about £130 for the head to be skimmed... new valves and guides.... and i spent Christmas learning to shim the valves and re assembling it.
    Went first turn of the key and ran beautifully after.
    Was a lovely car to be fair... was a bit heavy but safe predictable handling.
    The 1.7 Renault engine was smooth .
    The starter was a pig to change as it's down the back.... and the clutch was a heavy job... RIP D978CDL.
     
  9. My Stag has 2 timing chains, 1 for each head. The book says change at 25,000 miles. Mine will be due again soon. Not a difficult job but time consuming. Don’t think I’d attempt doing a belt change on the Ducati.
     
  10. Changing timing chains at 25k?!?!
    Lowest mileage timing chain change I have done was on a 60k seat leon with the vw TSI engine... quite prone to cam chain stretching.
    I replaced my cam chain in my Kawasaki ZXR 400 at 18k but had head off for a new head gasket... so did it all at same time.
    I have done a few Ducati belts over the years...so far no problems.... he says very quietly....
     
    #90 Peter J748s, Dec 24, 2020
    Last edited: Dec 25, 2020
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  11. Are you copying me?:)
     
    • Funny Funny x 1
  12. Fat fingers....posted before had written comment... now editied
     
  13. you can't compare car engine cambelts to Bikes, you just can't, different rotation speeds, thickness, different loads etc.

    Personally I'm not sure I'd leave any belts too long, my 848 Evo belts were 2.5 years old and I had only done 2k miles and a trackday, and I checked the belts and they just looked like they had been really hot and the rollers looked pretty 'rusty' from moisture ingress, so it's not always the belt that's the problem, if a roller seizes it's game over.

    I found out the other day from my mate that when he had his first 748r a few years back, the guy he bought it from who was 'a Ducati Specialist near Silverstone' fitted standard belts to R wider pulleys...... what a pikey thing to do.. the good news is they didn't snap in the first 6 months and trackday he did, but still shows that maybe they have slightly more margin for error than some think.
     
  14. Belts on desmo timing gear engines have practically no torque load on them, so the failure mode is normally different to valve spring engines.
     
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  15. I think I could almost do the belts on a Carbie 900 blindfolded now I've done my M900 so many times, plus my 900SS.
    I'll be doing my 1000SSie in the spring too.

    I've done a few cars over the years now, but the two worst I've done were:
    My Subaru Legacy GTB Twin Turbo estate was really difficult, mainly because the Boxer engine is so wide, and with two banks of twin Cams the belt was the longest I've ever seen. Plus access was very limited. Loved that car but it only did @18MPG most of the time and I wanted to tow a bigger boat.

    The most scary however due the cost of getting it wrong was the belt on my 2005 Discovery3 2.7 V6 Diesel. Again with two sets of twin cams, but so many pulleys and far more complicated to time up properly. They need changing every 7yrs or 105K miles. I did them twice in 7yrs due to buying it with 80K on the clock and the mileage I did.

    The tension on both of the above was easy though, with new tensioner pulleys you put in place and pull a pin out of to release the tension.

    Thankfully it will be a couple of years before it will be time to do the belt on my 2015 Discovery4 3.0 V6 Diesel, but that will be when it's 7yrs old not due to mileage.

    Nasher.
     
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  16. Yup, 25K. It’s late 60s engineering (engineering term used loosely)
     
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  17. Nissan still use that engineering for their chains, 43,000 miles on my wife's Juke :confused:
     
  18. just to re-iterate, unless you'd changed it very recently, you'd have to be a complete and utter idiot not to renew your water pump while changing your timing belts on an 8v or 16v Integrale
    a bit rusty and lacking in confidence at the original time of posting, but caught up with some mates at LMC Trackday recently, and if in any doubt, ask a renowned expert who knows what she/he's talking about.
    If you are someone who loves spending extra hours grunting and heaving away under the bonnet doing your own maintenance then that's up to you, but for anyone paying to have their belts changed it's a total no-brainer.

    https://www.integralingham.com/water-pump
     
    #98 Chris, Sep 18, 2021
    Last edited: Sep 19, 2021
  19. 25k is scaremongering, biggest problem on stag timing chains was the tensioner plungers siezing up due to excessive carbon and sludge build up inside from crap oil that wasn't changed often enough and the fixed chain guides used to lose their rubber coating which then loosened the chain tension and allowed the chain to run against bare steel. That is what fucked the chains.
     
  20. I'm convinced that there is fair element of FUD when it comes to belts
    I come across this a lot in computer security ( Fear , Uncertainty , Doubt )
    ...... and the FUD spreaders are usually looking to sell you something on the back of it .

    BTW - do you still have that Two-pronged Crown ?
    I know someone who is looking for one ..... :D

    I'll probably get flack for saying this ..... but if the pulleys rotate nicely and the belts look good , all over
    then they likely are good .

    A few years back I searched around for pictures of failed belts , and I couldn't find one of a snapped belt
    that didn't also have some clearly visible damage , away from the break point , and which
    must have been there for quite a while before the failure .

    eg. damaged teeth , frayed edges , or tiny cracks on the smooth side of the belt .

    :bomb:
     
    #100 oldtech, Sep 19, 2021
    Last edited: Sep 19, 2021
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