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If we are to listen to your advice about the replacement of cam belts at ever decreasing mileages, isn't it about time for the manufacturers to design engines with easily replaceable cam belts? Surely it should be possible to effect the change as easily as fan belts. Why is it so difficult and expensive?
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You have to take the front bumper off a Passat Tdi!
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Rob - consider yourself lucky. Audi Coupe 5 cylinder - remove front bumper, remove secondary radiator (yep, it has two of them), lift front of car about 6 feet in the air (can't get to the crank pulley from above) then undo crank pulley nut which is done up to 350lb ft! 2 special tools needed - a locking plate to hold the crank pulley in place, and a torque multiplier to shift the nut. Just for once, I got a garage to do the job.... On the other hand, the four cylinder motor is the easiest I have ever seen for cam belt changes.
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Or just buy a Mercedes with a double link chain. As long as you keep the oil clean you'll be alright. I'm sure there's a very good commercial reason why most cars have belts though
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On a 1.8i Cavalier, the alternator belt goes through an ENGINE MOUNT would you believe. On trying to change it, what should have been a 10 minute job turned into a 4 hour, prop the engine and and remove an excpetionally awkward engine mount. Bearing in mind you also have to go through the rigmoral for the cam belt as well... I really believe manufacturers either give no thought whatsoever to service times etc when designing cars or it is used as a means of forcing the car to spend more time in (they hope) their garages and earning more money for them.
What does everyone else think?
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As someone who is charging others for these jobs I hate the difficult ones because most of the work isn't the skilled part of timing/tensioning but getting at the thing in the first place.
To have to remove turbo inlet pipes, radiators, pas pumps, drivebelts, engine mounts and all the rest is a waste of time. It's more things to break, more clips to lose and so on.
Worse of all must be the ones where the engines are so close to the offside inner wing there is hardly room to withdraw the cover fixing bolts. In some places there isn't even room to get your hand in to work. On such engines,by the second belt change,half the fixings are usually missing because it was just too hard to see how to get them back. On some Xantia TDs there is one belt cover bolt that is near impossible to see/remove without taking the engine out, it can take 20 mins of cursing and a temporary retreat for coffee before you get this one out.
I'm convinced all the trialing of belt changes at the design stage is done with the engine on a bench.
David
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from memory, belts seem to arrive in the late 70's and were promoted as being quieter than chains. My neighbour had a honda civic in the mid 80's with 80,000 miles on the clock, the original belt and a recommendation from honda to never change it. To my knowledge it never broke. Ford seemed to perfect the art of the early cam belt breakages on the mkiii cortina (pinto engine) and carried this art into the mkiv and v cortinas, early Sierra's and fwd escorts with breakages as low as 25000 miles and a recommended change interval of 30,000. It seems to me that belt-life has not improved with age. I suspect that the main reason for their continued use is cost and I suspect that cost is driving the introduction of plastic tensioners which may also contribute to early failure. I'm pleased that my 95 primera has a chain.
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My own memory is that cambelts arrived in the early seventies and, perhaps, someone might have more information to enlighten us. I seem to remember that it was Fiat with the 124 (Yes, the one that became the Lada) who got a belted car on to the market first. Ref the view that the layout is too complicated, I agree entirely and I put it down to the manufacturers who jumped onto the bandwagon with engines basically designed for chains but hurridly converted to belts. If such a major component has to be attended to so frequently, surely the replacement procedure could be made more straightforward ?
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if you buy an early lada, these cars have cam chains, i had one of these cars, and i never changed the chain. on the other hand, all ladas with a cam belt, are very easy to change cam belts because of the VERY basic engine, brill.
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V interesting replies/comments - I shall now worry until I sell my cars! Should these messages be categorized as originating from professional mechanics or consumers? Clearly it is in the formers' best interests to advise frequent replacement!
'poking at an old wound' is a false analogy [I'm a GP]
'don't retension old belts' - I have just bought my son a Peugeot 309 from the auction for the grand sum of £285 - allegedly 99,000, cambelt slightly loose so I tightened it [don't know if original and don't care] - it looks ok.
It's obviously a risk but if you pick engines with a good reputation it's worth a bit of fun taking it - and anyway I enjoy tinkering. Just as it is rarely worth repairing cameras or electronic goods, perhaps we are now in the age of disposable cars - at least as far as cheap second-hand ones are concerned.
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My first knowledge of cam belts was on Bedford CF vans in the late sixties .Vauxhalls first overhead camshaft engine in the UK also fitted in the victors .
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Chains are thought to be foolproof, sometimes. The secondary chain (the one that runs round the camshaft sprockets) broke on my XK150 years ago and scrambled the top end somewhat. Had it fixed, but it never went as well; and yes, the oil was changed as per best practice. It only takes one duff link.
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My Audi has both - belt drive to one camshaft, then a short chain across to the other. Double the chance of something breaking? And from my biking days, I well remember fiddling around with stretchy cam chains and fragile tensioners, and wishing that Japanese bike manufacturers would use belts instead...... If only Ford had got that two stroke Fiesta engine to work properly.
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hONEST jOHN WILL KNOW,BUT WAS NOT THE INFAMOUS COGGED BELT THE BRAINCHILD OF ON E hANS gLASS?
i THINK IT ALL GOT OWNED BY vw-AUDI IN THE END.
i HAVE NO DOUBT THAT A BELT THAT LASTS FOREVER IS TECHNICALLY SIMPLE.
bUT MANUFACTURERS ARE ONLY BOTHERED ABOUT THE FIRST 3 YEARS.
aND YOU WILL PROBABLY WHINGE IF YOU HAVE TO PAY £100 FOR A BELT THAT IS NEVER ,THEORETICALLY,NECESSARY!
mODERN CHAINS ARE REALLY MUCH BETTER THAN THEY WERE.
tHE fwd oLDS tORONADO TRANSFERRED THE WHOLE POWER OF A BIG v8 TO THE GEARBOX VIA A mORSE HI-vO CHAIN,WITHOUT ANY PROBLEMS i EVER HEARD OF.
iTS JUST THE OLD STORY,WHAT YOU GET FOR CHEAP IS CRAP.
wHICH IS MAKING MY PURCASE OF A XSARA 110 td VERY WORRYING.....`
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stop shouting, i have a bad headache.
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RObin,
Could you turn your CAPS LOCK off, please?
Andy
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glad to see the cambelt debate going strong. I've had VWs/Audi and never change them, just inspect. If it works, don't mend it.
Passat GL5 changed at 135,000 when water pump failed - went on to 192K when I sold it.
Audi 100 2.0 [samish engine] 138,000 - looks ok.
Passat 2.0GL 192,000, curious whine at 160,000 traced with my stethoscope to tension pulley about to seize - pulley replaced, belt left in situ.
I believe belts only fail if they are allowed to get too loose or, more often, a tension pulley seizes and friction-fries it. There is virtually no load once the head gear has loosened up so they should last for ever.
Beware exchanging the original quality product at 60,000 with a duff cheap belt which then comes apart at 85,000.
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john fitton wrote:
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> There is virtually no load once the head gear has loosened up so they should last for ever.
>
Sorry, John - I don't agree.
Once the engine's running the load is fairly minimal but the greatest stress is induced in a cambelt BEFORE the engine fires, i.e. on start up. I had one snap on a Cavalier and that's exactly when it went.
Ian
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John
There actually is quite a load on these belts, and it's by no means constant. I'm sure the experts will correct me if I'm wrong, but most failures happen at lower speeds - often in traffic. The problem is that in traffic the load on the belt is constantly changing as the engine accelerates and deaccelerates.
As for inspection - well, the load carrying member is the cording within the belt and that's invisible. Once there are visible signs of wear or cracking things are really bad, and failure is almost upon you.
I think you've been extremely lucky so far - plus you've had cars where inspection is feasible. I reckon the costs of failure make regular changes a good insurance premium.
Regards
John
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John,
I have to agree with Andrew, if you go into any larger dealership there will be tales of cambelt failure most weeks. Locally they have one lady who has broken the belt on her Citroen Xantia TD this year, having done the same to her Mondeo TD last year....about £1000 a time!
If you see my earlier post you'll notice I take no pleasure from the lengthy times and higher charges on complicated set-ups.
What I can say is it isn't possible to check a belt properly without removing it as the start of failure is so often a crack on the inner root of a tooth. The only way to see this is to remove the belt and turn it inside out. And if you remove the belt to check it then replacement is a cheap and wise option.
In the last month I've had in two belts to do that were split about 30% of the belt thickness, from the inside. One was a Citroen TD and that going could have scrapped the head and ended up at near on £1000 to resolve.
I would never re-tension a used belt as they stretch each time you do them and this must increase the risk of failure.
You really are poking an open wound here John...if you'd ever had to face a customer with the estimate to sort out the result of failure you'd be with regular changes evey time! As it's DIY in your case the result of failure can be sorted with a shrug of the shoulders no doubt
David
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My first knowledge of cam belts was on Ford BDA's, mind you, the damn thing was apart so often belt life didn't really come into it.
Again if you did not sort out the extra oil feed to the camshaft bearings when the engine was getting some stick they could partially seize and then the fun started.
Never thought it would catch on in mainstream engine design, just shows how much I know. There was I thinking here's an out and out racer of an engine, 1800cc four pot 16 valves belt driven twin cam, now I drive a diesel with more or less the same spec except 200cc more and a turbo, hey ho.
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I think John Fitton has been a VERY lucky boy. I changed the rotten belt on my rotten espace at 36000 miles (1/2 distance) and the roots of the teeth were cracking then. The "designers" of these engines ought to spend a day out in the field with some of us working on their darling contrivances then perhaps they would apply a little thought when conjuring up some of the crass installations we have to deal with. And can anyone tell me why everybody seems to be re-inventing just about everything at the moment? Notable example is Ford hub nut which has developed from a simple piece of hexagonal bar with a thread in it to a multilayered sheet steel fabrication which strips the thread off the hub as you undo it!
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has John Fitton ever tryed turning a camshaft by hand,its not easy and makes you appreciate the load on a belt from standstill. Dont turn it far on an assembled engine if you do. david
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