The timing belt on my 94 1.8 Mondeo lx zetec has snapped!!!!! I didn't hear a bang as such will the valves have bent? I was slowing down for traffic light's at the time, if this makes any difference!!
Thanks in advance,
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I've never done this but here is my suggestion.
Remove the plugs and rotate the crank by hand till each piston is away from TDC (use a coat hanger wire? if you cant see the pistons?)
Then rotate the camshaft and check the max valve clearance for each valve. Too big a clearance indicates a bent valve. Some engines are non interference types (no idea whether yours is) or you may just be lucky.
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all the pistons will be at max clearance at 90 BTDC or 90 ATDC
good luck and fingers crossed
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Banger - I think you'll be extremely lucky not to have suffered any damage....sorry
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Can I ask is it the original belt/what mileage has your car done?
I'm a loser, baby....so why don't you kill me?!
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Miller,
I think it may be (original), 101000 miles so not bad going if it is! Ford have quoted me £720.00 for rebuild, £300.00 by an independent garage!!! I know some engines don't collide when the belt breaks, just wanted to know if this was one of them or am I being taken for a ride.
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Sorry I cant be of any help on the technical side of things, but if the damage is done the £720 Ford has quoted is bordering on the value of your car anyway and not economiclly viable. If the independent garage has a good reputation it may be worth going with them.
I'm a loser, baby....so why don't you kill me?!
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hi
this may be a long shot but my mums old sierra (recently discussed) her cambelt snapped at 90 thousand miles as 15 miles per hour the head was taken off for inspection and found no damage.
the engine was a 2 litre sohc 8 valve pinto
Regards
J Stephenson
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Banger,
You won't get away without any damage on this engine, I'm very sorry to say. If you recon this belt has done over 100,000 miles then why on earth didn't you change it sooner?
Bearing in mind the age of the car, I would say the only realistic way of fixing it would be to get a second hand engine dropped in. If it were mine then that's what I would do.
Obviously one takes a chance in this situation, but if you ask the right questions beforehand, I believe the chance can be reduced. If you get it done by a garage you know, they will know where they are likely to get a decent second hand engine from, I think this is the way to go on this one.
What do other members of the BR think?
Good Luck!
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hi
if it was at such a slow speed then the damage must be minimalistic
Regards
J Stephenson
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Do not turn the engine over. Fit a new belt and do a comprssion check on all four cylinders to establish damage and take it from there. Good Luck. Regards Peter.
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J - it's the speed of the engine that counts, not the car. My daughter's 205 belt went (at 51K miles, not long after a Peugeot service) just as she pulled away at a roundabout. Needed a replacement engine.
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Minimalist damage? All light wood, glass sparsely placed black leather? I like the theory...
Seriously James, a car doing 15 mph in second will likely be at 2,500 rpm or so, about the same as 60 in top. I would expect there to be damage on virtually any engine unless it is specifically non-interference.
A Pinto engine, an old design admittedly, is one of those that would survive a belt breakage as a matter of course. On something newer like a Mondeo, this is of course different.
As for getting a good secondhand engine - why? It's highly unlikely to cost less than the £300 quoted by the independent garage, which actually sounds rather good - not all that much more than the cost of a belt change on some cars.
If you feel confident doing the compression test and fitting a new belt, there's no harm in trying but if you aren't, and you trust the independent, go with them.
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2.0 Pintos have a compression ratio of 8.75;Zetecs are 10.2 if I remember rightly.So there is a lot more space in the combustion chamber.
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if it was at such a slow speed then the damage must be minimalistic >>
James, I think you are making a wild stab in the dark rather than coming to an informed judgement.
Have you seen my posting on another thread about the water pump on my son's Renault Clio siezing? The seizure led to the belt, the camshaft and drive sprocket breaking, as well as bending of the valves. That all happened at 30mph when he was in the action of changing into top gear during leisurely acceleration! I assume (wouldn't go so far as to say "it must be") that the pump seized just as he was about to drop the revs for the up-change into top but that still wouldn't have been at a very fast engine speed.
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if it was at such a slow speed then the damage must be minimalistic
James,
1. Take one perfectly good valve and place the stem securely in a vice.
2. Take a hammer and hit the mushroom part of the valve at an angle at a similar speed to what a piston would be travelling at when the engine is doing 2,500 rpm.
3. What is the outcome? Chances are the stem of the valve is bent.
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101,000 sounds like good engineering if Ford claim 100,000.
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I think you'll need to assess first whether the valves have been damaged/bent, and this can be done by a compression check on each cylinder. If all clear then maybe all that is needed is a new belt. If they have been damaged, then a strip down of the top end is required to replace the valve(s). Then can assess whether other damage, e.g. to pistons, bores, has occurred. Just my suggestion based on what happened below.
Our Vento 1.6 cut out at low speed, and could not be restarted, due to a failure of the cam belt. This failure caused damage to several valves and 2 hydraulic tappets. The car had 72,000 miles service.
Prior to this, the vehicle has been regularly serviced, at the correct intervals.
The engine was repaired which involved replacing all 8 valves, (may as well have it done although only 2 were obviously bent) 2 hydraulic tappets, head gasket, cylinder head bolts cam belt and sundries such as oil, filters etc. In total the parts charge came to £315.31. VW paid the labour. We paid for the parts.
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Gents,
I would not do a compression check first. Suppose you take the time to fit a new belt and the valves are bent.
You turn the engine over (by hand first I would hope) and find resistance when the bent valve meets the piston and strain the new belt in the process only to take it all off again.
£300 for the effort involved does sound good, maybe too good, is everything covered here? I think I would not take the trouble to DIY at that price.
An engine can?t have minimalistic damage really can it. Either the valves are bent and need replacement or not. If the clearances turn out ok then fit a belt and turn it over by hand. If that?s ok briefly do a compression check on each cylinder. If that?s ok put the plugs in and fire up and if it idles ok have a £300 party or whatever.
As above, digits crossed. From what I read on these things Galaxy is probably right, that why I?m a camchain man myself, I can sleep at night.
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£300 to put right does sound a tad cheap.
A friends 1.8 cam belt snapped and he had the engine repaired, it didn't run right until they rectified the bottom end damage (I can remember if a con-rod was bent or a bearing had gone, but it dragged on for months)
Agree with all the sentiments about damage, think of the intertia behind a car rolling at even 10mph and then you put the valves in the way of the pistons?!
Best of luck
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Revs really have nothing to do with it - if there is insufficient clearance the valves will contact the pistons, and it only takes one revolution to do it.
Have never heard of a belt failure on this engine not causing damage, just a question of how much. £300 can only be a second-hand head being fitted, without any work to check valve seats etc. TOO CHEAP ! If piston crowns have been damaged there will be more tears in the not-so-long term. Bent rods should be evident by measuring piston crown-to-cylinder head clearances on all 4 pots - ANY difference indicates a problem.
This engine needs examining by a skilled engineer before just bunging a replacement head on it.
Regards, Adam
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2.0 Pinto's belt can break without any problems,1.6/1.8 you may be lucky,1.3(not sold in UK)smashes the valves every time but then it takes a lot less than 1 hour to change the belt on Pinto.
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Whilst not specific to this engine, it does raise some interesting questions.
I believe that the 2 classes normally used are
a). Valve safe = piston to valve clearance exists at all times.
b). Not valve safe = piston to valve contact CAN (not will)occur.
For engines falling into group b) some designs will not cause damage under certain circumstances. This is dependent on the position of the camshaft when failure occurs. Damage will occur where the inertia of the cam shaft allows it to continue to rotate after the belt breaks, thus ensuring valve contact takes place. The inertia will be dependent on engine speed, however the stiffness of valve springs presumably has an effect on the how quickly the cam shaft will stop.
Presumably there are some engines that have clearances that will ensure contact takes place irrespective of the position of the camshaft. ie you never get away with it!
I speak from a lucky experience with a Volvo 240 B230A that survived a belt failure at about 2500rpm. It has made me very conscious now of adequate changes!
Can anybody add to this?
pmh (was peter)
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Sorry, but position / movement / inertia of the camshaft is not rellevant. The cam(s) stops the moment the belt fails, and at any position of the cam(s) at least 2 inlet and 2 exhaust valve(s on a multi-valve engine) will be at least partially open. The crankshaft/pistons, however, will not stop due to the latent energy/inertia of the flywheel/vehicle, and thus the damage is done.
Again, if there is clearance there is clearance, if there is not there is not.
Regards,Adam
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Hi
When i say SLOW speed i mean slowing down at traffic lights
Regards
J Stephenson
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Adam
How then do some engines that are not valve safe survive a broken belt? is the clue in your comment 'partially open'.
I was initially surprised when somebody suggested that the camshaft would have enough inertia to continue (abeit only a fraction of a revolution) but this seems to explain why some engines do not always suffer damage.
pmh (was peter)
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Thinking on this, the belt will break when under the most stress, that is when the greatest number of valves are reaching the top of the lobe. At that time the cam will stop, leaving valves at the most vunerable position possible. Only if the pistons stop within probably 1/2 a rev will they be saved.
If the engine is idling I think that is just possible. Try it, have someone turn your engine off and note how many degrees the crank continues to rotate.
The inertia is low and the effort required to compress one cylinder (its 4 stroke, 4 cyl) may stop it. But if you are in gear,that different, the car inertia will garantee distruction
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I *almost* agree with Adam about the cam(s) coming to a sudden stop when the belt snaps. On the other hand, I wonder if it might be possible for inertia to continue to rotate the camshaft for an extent since not all the forces between camshaft and valve are acting against turning - as I'll try to elaborate ...
The valves that are being opened by the camshaft are applying a load that, in effect, is trying to stop the camshaft turning. However, and at the same time, the valves in the process of *closing* are applying a forward-turning force to the camshaft by virtue of the springs pushing the valve unit down on the trailing slope of the cam. (A major reason why unitary valve operation hasn't taken over from camshafts is that an opening valve doesn't readily get help from a closing valve.)
If the inertial forces in the camshaft exceed the power needed to rotate it, which might be the case since not all forces are opposing rotation, then the camshaft could possibly continue to turn for a bit as has been suggested.
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surly the first action must be to remove the head and check for damage? then given the age of the car perhaps fit a second hand/recon head, assuming no visible piston damage and taking a chance on the conrods being ok.
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Poke an endoscope down ze pughole. Saves major surgery and financial anaesthetic. Compression tests don't need the cam-belt, just a rotation of the cam. Non intrusive, like long service intervals are designed to be!
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This must be the best reason for avoiding ivestigative procedures on a Monday morning, after the staff have borrowed the kit for the weekend!
pmh (was peter)
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I remember spending hours trying to convince someone that when the engine was on the overrun the camshaft didn't go on the overrun as well.
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Roatating the crank to positions the pistons at 90 before or after TDC won't help you. You'll need to rotate the cam shaft and examine the maximum clearence on each valve.
It may be worth your while, with no cam belt to link cam to crank, to position each valve at fully open and rotate the crank slowly to see if each piston makes contact with the corresponding valves. If they don't then you may be in luck.
If they do then repeat the test with each valve fully closed (ie not 'on' the cam). If contact is again felt you have a sticky valve in the open position, which could be bent.
If after doing this you feel comfortable or think 'what the hell' Get a cambelt and fit it as per the Haynes workshop manual instructions and slowly rotate the engine again to see if contact is made between valves and pistons. If not fire her up.
What have you got to lose apart from the cost of the cam belt?
Then see how she runs. A compression check will confirm whether or not you got away with it.
If you suspect there is contact and damage is done, you could remove the head yourself and check this and the condition of the pistons. If the pistons are OK then you may be able to get the head rebuilt for less than the £300 and refit it yourself.
If a piston is damaged I suggest replacing the car, You should be able to get a few quid for spares I would have thought.
H
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Banger.
Any update on this?
H
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Banger. Any update on this? H
yeah, come on, banger, tell us.
or are you like many of the others who post a question, and then disappear into the ether without any thanks, or at least some feedback?
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Go easy on him eMBe :-)
He probably has a lot on his plate, especially if he hasn't sorted his transport out yet?
H
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Further to a thread that seems to have disappeared, 3/7/03. An update on my 94 Mondeo with a snapped timing belt. Six valves were found to be bent, and as suggested on this board the price of £300.00 was to cheap!!!
Due to the fact it has a 16 valve head my mechanic thinks the valve guides would need re-machining the cost of this alone comes to £400.00!! Plus £300,00 for timing belt kit, gaskets and fitting!!!
Ended up going down the re-con engine route, firm in Charlton SE7, £675.00!! Price includes, oil, antifreeze, and fitting, with a 2 year guarantee.
Thanks for all your useful comments on this board, let you know how it goes.
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Further to a thread that seems to have disappeared, 3/7/03...
No it hasn't, it's here www.honestjohn.co.uk/forum/post/index.htm?v=i&t=14...8
I will incorperate this thread into it later on, just so it keeps everything all in the one place.
Thanks for coming back and giving us an update, btw.
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Cheers DD,
Didn't know their were any more threads past 33, so I'm glad I clicked on the link to see some more messages for me.
Pleased I got back with an update, I didn't know you guy's cared so much!!!
There's a new bit to the story now, bank willing to lend me £12k ( the fools) for new or newish car.
Do I keep the Mondeo for another six month (mummy thinks I should) why get in all that debt????
Went to Trade Sales in Slough Sunday night in rental Vectra!! Seems like a nice car, can't think why people hate them so?? They had a 52 plate 2.2 SRi in black for £10,999.00 with 11k on the clock!
Or get a 5 year old 5 series always wanted one, now I have the chance.
I might have gone off the thread abit, but you guy's were asking me what's been happening!!!!!
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I'm looking at a new car too. H plate 1.6 golf driver for 250 quid
;-)
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5 series - without a doubt. You'll probably feel obliged to service a newish vectra at a main dealer that will probably cost similar to a 5 series at a specialist.
Also the vectra will be worth £1.32 in 3 years whereas the 5 series will still be worth £5k or so.
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Banger
Thanks for the update, sorry to hear the dmage was as bad as it is.
If you're going to replace the engine, I would look at 2nd hand. If you look hard you could find one at about £300 with 6 months warranty (plus fitting). Reasonable miles.
Personally, if the damage was limited to the head I would have thought about just replacing that. A recon head may have only cost you around £200 to £300 plus fitting. 2nd hand poss about £100.
If you have spent that money on the car, I should save getting the loan till later and get the value back out of that car till it drops. You've probably got another 4 years in that car now, and even then you'll get a couple of hundred for it if its got some MOT. If you trade it in now you may get £800 for an L reg 16v.
If your intention was to get another car anyway, I would not have changed the engine, but advertised the car (spares or repair) £250 and see what bit. Someone with a 3rd party writeoff may have been tempted.
H
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