Hi there,
Just a general knowledge question.
Say im driving and my camblet snaps how will i know?
Does it make any sound..does the car loose power?
when the cambelt snaps will the car not start at all?
Sorry for sounding a little stoopid but aint really got much motoring knowledge.
Any info appreciated.
Regards
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If it's an interference engine then I can assure you that you will know... As the pistons whack the valves there will be noise and loss of power.
And your bank account will certainly notice it!
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Does it make any sound..does the car loose power?
Oh yes, all of it.
when the cambelt snaps will the car not start at all?
No. Don't even attempt to restart it if you know it's the belt.
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Mike Farrow
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When the belt on my old cavalier went it made no sound but the engine died as I tried to put some revs on to get onto a roundabout. It failed to restart but popped a few times. Green flag arrived, took the distributor cap off and showed me the freely rotation rotor arm. They then towed me to their garage showed me the bits of the old belt - fitted a new one, took about £50 off me and off I drove.
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When the belt on my old cavalier went it made no sound but the engine died as I tried to put some revs on to get onto a roundabout. It failed to restart but popped a few times. Green flag arrived, took the distributor cap off and showed me the freely rotation rotor arm. They then towed me to their garage showed me the bits of the old belt - fitted a new one, took about £50 off me and off I drove.
The Cavalier was a mechanic's dream, to change a clutch was so easy. Sadly on most cars now if the cambelt snaps, you're in for expense as the pistons hit the valves.
I sense a debate on belts v chains coming on...
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1980's/90's Cavaliers and Astra engines are the only ones I know of that a broken cam-belt doesnt result in catastrophic top-end engine damage.
I would say that on most other cars a broken cambelt would result in a bang and lots of other horrible noises which immediate loss of all power.
In short, you certainly would 'notice' if the cam-belt breaks !!
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My dad once suffered a broken cambelt with a difference whilst on holiday in France. I don't recall him mentioning what the car was.
He tried to start it up one morning and it refused to fire, although it turned over ok. He enlisted the help of a nearby garage, who spent ages checking everything before it dawned on them. "Ahhh! Timing belt!" came the eventual French exclamation.
Seems it had given up the ghost just as he switched it off the previous evening. How unlikely is that?!
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The Ford CVH belts often seemed to snap when starting the engine - high load I guess?
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1980's/90's Cavaliers and Astra engines are the only ones I know of that a broken cam-belt doesnt result in catastrophic top-end engine damage.
Add Mazda MX5 and others based on that engine to the list.
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When my old orion 1.8d belt went, there was a strange noise, the engine went 'tight' just ground to a halt. And yes, there was a big bill.
Splodgeface
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The cam belt broke on my wife's Volvo 340 1.7 one very frosty morning as she tried to start it. I imagine the cold made the rubber brittle. Got away with one bent valve.
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Amazingly, I can add my trusty 1988 Honda Accord 2.0EXI to the list of safe engines. Had just turned right at a junction then it simply died. Coasted to a halt. I suspected fuel pump, coil, computer, belt. Belt was the first to test, as I eased my finger behind the belt cover I discovered to my horror that I could feel a naked camshaft wheel!
Local garage asked me if I wanted them to bother trying (165,000 miles, 1988/E) I said yes because finances were so tight at the time. Amazed to receive a call some days later to say all ok - no damage whatsover.
That's the problem with a failed cambelt though - you have to pay out for a fix before you can tell if it's wreaked any damage!
Sadly, rust has meant that the Honda is now fit only for a scrapyard, now replaced with a 406 estate (some problems - see my other posts).
The replacement schedule was 60,000 for the Honda belt. It was last changed at 120k so it broke even before it's expected lifespan. This (premature failure) seems a common occurence, and may be due to belts being fitted too tightly?
Regards
Paul
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You can add the trusty old Volvo 4 cylinder engines to the list of non-interference engines. (240, 740, etc)
However, I read recently that the potential for damage is not just that the piston may hit a valve because the camshaft has become disconnected. It is possible even on a non-interference engine to damage a valve. Apparently it depends on where the valves happen to be when the mixture fires. Normally of course both valves are closed. But if one is open the explosion can cause damage.
It sounds plausible, but I don't know whether it is really true, or likely.
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Sorry Cliff, the 240 (2316cc 1986, the engine code 230xx ), is definitely classed as an interference engine. It caused me some mental anguish at the time. However about 30% of the times you get away with it - I did! if you look in the history there is a thread. It maybe that very early 240 (with small valves?) and some of the 2.0 variants are valve safe.
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pmh (was peter)
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Not wanting to get into a detail discussion here, but there has been a lot of argument in Volvo circles about the accuracy of some of the 240 range interference categories. I think the conclusion was that all the 8-valve engines are actually non-interference, only the 16 valve are interference. The was a lot of misnaming of the "heron" head engine.
I tried slowly turning a B230 when I last did a timing belt, it was definitely non-interference.
But whether interference or not, it would be no fun breaking a belt on a dark night miles from anywhere, so I have always followed HJ's advice to change at 50,000 miles maximum anyway.
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Before they went bust, Rover were working on a cam-less version of the K series. IIRC the valves were controlled electronically.
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My recent cambelt incident stimulated some debate on this forum about the safety of the PSA 1997cc HDi in these circs. Concensus was that, as might be expected for a diesel, it is an interference unit.
There are however some pictures and posts from Dave Woolard on the pictures area associated with this site (sorry can't link to it from here - Net Nanny throws her toys)which suggest it's realtivley safe.
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The PSA 3.0V6 ES9J4 definitely isn't safe... I've got a bill for nearly the value of the car to prove it :) When mine went there were none of the noises I would have expected - just a sudden loss of power. Had the radio on at the time but not that loud - it certainly wasn't immediately obvious that the problem was so catastrophic - indeed I was quite cheerful about it at first.
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Cliff, interesting comment. I just checked on Autodata (the Trade bible, which lists all B230 as definitely an interference engine. Your experience points to the fact that maybe it is only marginally safe, tolerance on valve clearances, valve stem length, head skim, head gasket thickness could presumably combine to make it valve safe. But I would not rely on it!
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pmh (was peter)
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...and the 1300 Triumph Acclaim.
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16 Valve,and diesel Astra's and Cavalier's DO suffer if the cambelt breaks, bent valves, holed pistons and broken cam followers, very expensive as i have found out twice.
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i have expressed some views elsewhere
www.honestjohn.co.uk/forum/post/index.htm?t=31411&...f
to which mark(rlbs) has said
"Harmless entertainment which people should feel free to ignore if they wish.
so my contribution here to this harmless entertainment is:
how come audi80tdi starts all these threads and gets the hare running ( type in his name as author in the "forum search" ) but rarely comes back to them?
does he watch all the harmless entertainment unfold from the sidelines somewhere?
i got sucked in to replying to him once but really wish i had felt free to ignore.
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For some reason we have had a bunch of school children show up. I'm guessing that its either holidays or they are the types not to be taking exams.
You missed by further comment to this guy, and also the fact that I have disabled him - and about 5 others, and given about 3 others the benefit of the doubt, for know.
Just don't rise to them - its pretty sad if some frustrated 16 year old can get a rise out of you lot. And its hardly new, it happens every year around this time; and again just before Christmas.
And if there is an interesting conversation, who cares that it was started by a child ?
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