Discussion
Hi all,
How realistic is the current mania about cam belts going twang???
I've recently replaced the belts on two of my toys because a) I could, b) I have the time, and c) I wasn't sure of the service history. My other toys use God's own engine with its trusty chain driven system.
It seems that garages have cottoned on to a nice little earner by scaring people into thinking that the belts need changing every 36K miles or so to the extent that no-one will buy a used Ferrari (per the Pistonheads Ferrari/Maser/Lambo forum) without new belts. Short of removing it you can't really check it and yet it's supposed to be able to break at the drop of the hat, with cataclysmic consequences. "I know the manufacturer says 72,000 miles sir but we have been advised to bring this forward to 36,000 miles now." Brittle belts, duff tensioners, whatever.
Thing is, a lot of cars now use OHC + belts and a lot of cars, especially those over 5 years old have probably done some miles with the benefit of minimal servicing. So by rights there should be cars strewn along the hard sholders with bust belts.
"Ah but just think of the damage Sir if it does go. This way it's only £500 every other service."
My feeling is that more engines get trashed through errors in the fitting/tensioning procedure and other items disturbed during the swap than actually go twang.
A question- has anyone here experienced a breakage or know anyone who has???
Cheers
Ian
How realistic is the current mania about cam belts going twang???
I've recently replaced the belts on two of my toys because a) I could, b) I have the time, and c) I wasn't sure of the service history. My other toys use God's own engine with its trusty chain driven system.
It seems that garages have cottoned on to a nice little earner by scaring people into thinking that the belts need changing every 36K miles or so to the extent that no-one will buy a used Ferrari (per the Pistonheads Ferrari/Maser/Lambo forum) without new belts. Short of removing it you can't really check it and yet it's supposed to be able to break at the drop of the hat, with cataclysmic consequences. "I know the manufacturer says 72,000 miles sir but we have been advised to bring this forward to 36,000 miles now." Brittle belts, duff tensioners, whatever.
Thing is, a lot of cars now use OHC + belts and a lot of cars, especially those over 5 years old have probably done some miles with the benefit of minimal servicing. So by rights there should be cars strewn along the hard sholders with bust belts.
"Ah but just think of the damage Sir if it does go. This way it's only £500 every other service."
My feeling is that more engines get trashed through errors in the fitting/tensioning procedure and other items disturbed during the swap than actually go twang.
A question- has anyone here experienced a breakage or know anyone who has???
Cheers
Ian
i had a 2.0 pinto break but that was 115000 and it dont matter anyway as it doesnt hit
a lot of modern cars use tensioners made of plastic and this indeed does break up seen it on gm lots and fiat too but when tensioner breaks cam carrys on turning meaning all valves get hit ouch!!! look at the ones you took off ian - bend them wrong way and look for signs of cracking - personally i like a change at 40 000 as lots of manufacturers changed their minds from the 60 - 72 000 miles and specified 40 000 instead i also think time has a bearing on what you decide to do say 5 years or so and maybe just to be safe if engine hasnt been used at all for a couple of years
guess whats planned for "good" friday?
cambelt and tensioner change on 1.4 12v fiat brava about 1000 miles over its 72000
apparently they have no timing marks either which should be fun tippex everywhere
on old engines like pintos etc its so easy you can just carry a spare incase it goes on expensive modern stuff where replacement involves lots of stuff coming off and that hits it seems a good idea not to over test it.
a lot of modern cars use tensioners made of plastic and this indeed does break up seen it on gm lots and fiat too but when tensioner breaks cam carrys on turning meaning all valves get hit ouch!!! look at the ones you took off ian - bend them wrong way and look for signs of cracking - personally i like a change at 40 000 as lots of manufacturers changed their minds from the 60 - 72 000 miles and specified 40 000 instead i also think time has a bearing on what you decide to do say 5 years or so and maybe just to be safe if engine hasnt been used at all for a couple of years
guess whats planned for "good" friday?
cambelt and tensioner change on 1.4 12v fiat brava about 1000 miles over its 72000
apparently they have no timing marks either which should be fun tippex everywhere
on old engines like pintos etc its so easy you can just carry a spare incase it goes on expensive modern stuff where replacement involves lots of stuff coming off and that hits it seems a good idea not to over test it.
I know of an R plate TD Escort that snapped its belt at 30,000 for no apparent reason , owner was far from happy when it all self destructed at start-up!
One of the biggest problems is cam belt driven water pumps , just that little bit of play in the pump pulley can let the old belt slip just enough to cause armagedon or lack of anti-freeze so the pump wont turn when the crank does.
Just before I sold our Rover Metro last month the water pump started leaking , they say you can re-use the cam belt but I took no chances and replaced it at the same time.
I had to rebuild the head on a Micra which threw its belt when the pump seized ,it was sat in contra-flow on the M62 , the free recovery service tried to jump start it for her on the hard shoulder thus bending all the remaining valves not just those bent when the belt went!
When ever a friend buys a new car I also tell them to get the belt replaced then they can be sure it hasnt gone over the mileage recommended.
Give me a x-flow with a timing chain any day....
One of the biggest problems is cam belt driven water pumps , just that little bit of play in the pump pulley can let the old belt slip just enough to cause armagedon or lack of anti-freeze so the pump wont turn when the crank does.
Just before I sold our Rover Metro last month the water pump started leaking , they say you can re-use the cam belt but I took no chances and replaced it at the same time.
I had to rebuild the head on a Micra which threw its belt when the pump seized ,it was sat in contra-flow on the M62 , the free recovery service tried to jump start it for her on the hard shoulder thus bending all the remaining valves not just those bent when the belt went!
When ever a friend buys a new car I also tell them to get the belt replaced then they can be sure it hasnt gone over the mileage recommended.
Give me a x-flow with a timing chain any day....
My only experience was with 1600 OHC Viva donated by a friend. Some teeth stripped and the crank went round but not the cam when leaving work one night. Got a lift to the all night garage for a belt, pushed car into reception, replaced belt using a long ruler to align the dots, then drove home. Lucky what?
brava / bravo same car cept 3/5 door and dif back lights oh how i hope its the 16 valve one that has to be dropped!!!! the haynes manual is confusing and doesnt really stipulate which engines theyre talking about. has anyone else noted that manuals are getting a lot less clearer - had same confusion changing 970cc suzuki sj410q santana belt - all instructions were about vitara engine - fortunately it was a simple design. anyone want to come help lol i'm sure theres better things to do in a jago than getting oily under a fiat have a good bank holiday guys
phew didnt have to lift engine there were marks but wernt really tdc or anythin just made my own after 72500 miles the belt looked knackareed very shiny and limp the teeth of belt were cracked and you could see impression of teeth on wrong side of belt it wasnt a happy looking belt oh and the tensioner was much stiffer on its bearings than the new one i'd say it was overdue for a change - if she still has it next one at 40 000 i think
Gassing Station | Jago Owners Forum | Top of Page | What's New | My Stuff