Cam chain bust on clk 230 komp

[Rodehard]

Hi all,

Looking at a clk 230 komp with bust cam chain what is this likely to cost? If you peeps here could maybe post a worse case least case scenario that would help.

Thanks

Rodehard

 

[tamrsoft]

I should look deeper before making a decision. If the cam chain broke then its likely that the pistons have collided with the valves resulting in a possible engine write off.

 

[panason1c]

Hi all,

Looking at a clk 230 komp with bust cam chain what is this likely to cost? If you peeps here could maybe post a worse case least case scenario that would help.

Thanks

Rodehard

Budget on a replacement engine from a breakers and you will be well covered. [Edit]..Bear in mind that the cam chain could possibly be a 'secondary' failure...the camshaft or crankshaft, etc, could have failed first....

Try this ..........

http://www.sniffydog.co.uk/index.htm

 

[C220GJS]

As said, look closely before committing yourself.
If the car is an automatic the damage is likely to be less as the engine stops almost immediately.
The minimum damage to be expected is bent valves and a damaged timing case ; in the worst case valves,pistons,timing case and a damaged crankshaft plus all the associated items.
You won't know the extent of the damage until you can strip the engine ,so unless you can do the work yourself I would say walk away.
Cheers, Geo.

 

[panason1c]

If the car is an automatic the damage is likely to be less as the engine stops almost immediately

When a cam chain (or belt) fails the damage that usually ensues is relatively instant and the whole event is over within micro-seconds and therefore any further engine revolutions due to the vehicle being in motion are not likely to cause further damage.

I'm not sure if being an auto makes any difference on a modern car ....On my ML auto, if i take my foot of the acceleretor i still get engine braking.......ie..the transmission driving the engine...

 

[Flying Scot]

When a cam chain (or belt) fails the damage that usually ensues is relatively instant and the whole event is over within micro-seconds and therefore any further engine revolutions due to the vehicle being in motion are not likely to cause further damage.

I'm not sure if being an auto makes any difference on a modern car ....On my ML auto, if i take my foot of the acceleretor i still get engine braking.......ie..the transmission driving the engine...

NOT TRUE

i have seen engines when the belt breaks when the car was pulling away from a stop and the valves were bent for sure but you had to run a dial guage on them to see the distortion. (happend to my sons car earlier this year)

i have also seen what happens on a belt that breaks at speed high revs and on the motorway - total destruction bent valves broken valve guides bent con rods holed pistions and damaged crankcase - the engine a total write off.

yes it only take a micro second for the belt/chain to break but until the engine stops you are hammering bits of the engine by other bits of the engine that were never designed to be in contact with each other - and these loads are transmitted throughout all of the rotating and many of the non rotating parts of the engine causing extreme carnage in a situation where the engine is rotating at any significant RPM OR being driven by the transmission as the car comes to a stop. You dont have an idiot light that comes on that says "cam belt/chain broken" - so when this happens you tend to put your foot down not lift off and dip the clutch - as you dont realise what is going on until you have identified the problem at the side of the road if you are technically minded or by the AA/RAC guy if under the bonnet is a total mystery to you.

 

[panason1c]

until the engine stops you are hammering bits of the engine by other bits of the engine that were never designed to be in contact with each other

Exactly....except that after the engine 'bits' were hammered the FIRST time they were instantly destroyed and subsequent hammering is by then academic.

 

[jberks]

I suspect anything over idle and its probably curtains. I've had one go on a CVH Ford. Normally a head off and rebuild job on those. However it was idling and simply stalled. Fitted a new belt and tried it anyway and it ran with good compression on all cylinders.

Maybe I was just lucky but I did wonder whether I got away with it because the compression in the cylinder was enough to stop the engine and I guess the cam will try to stop under with all the valves closed so subsequent starting attempts didn't do any damage.

 

[Flying Scot]

Exactly....except that after the engine 'bits' were hammered the FIRST time they were instantly destroyed and subsequent hammering is by then academic.

AGAIN i cant agree - having seen the difference between being hammered a few times at say 750 rpm and for about 2/3 seconds - my sons car - the belt let go when he was pulling away from the kerb - and 5500 rpm and say 20 seconds - my friends car which blew up on the motorway at well lets say somwhat illegal speeds the results were TOTALLY different.

We popped a complete set(eight) new valves in my sons car - really only needed three and two of them were marginal they would have ground in no problem i suspect - but hardly worth not doing a complete top end overhaul when we had the head off - after that it was as good as new - the other car needed a new engine - so all in all the difference was hardly acedemic.

 

[Flying Scot]

I suspect anything over idle and its probably curtains. I've had one go on a CVH Ford. Normally a head off and rebuild job on those. However it was idling and simply stalled. Fitted a new belt and tried it anyway and it ran with good compression on all cylinders.

Maybe I was just lucky but I did wonder whether I got away with it because the compression in the cylinder was enough to stop the engine and I guess the cam will try to stop under with all the valves closed so subsequent starting attempts didn't do any damage.

some cars - my Toyota for instance have non interference engines - there being no way the valves can hit the pistons even if the valve were to stick fully open the piston cant hit it a TDC dont know about a Ford CVH should be easy to find out on the Ford forum your camshaft cant stop with all valves closed not unless all the lobes fall off at the same time as the belt snaps - clever ford engineering

 

[OmniCognateNeutronRangler]

I think it depends on the car. I had a cam belt go at the traffic lights as I pulled away (faily quickly - and fotunately only about 100 yards from a garage) and it did no damage at all. Cost me about £90 to get the belt changed and continued to drive the car for about another year.

This was a Mazda 626

 

[panason1c]

AGAIN i cant agree - having seen the difference between being hammered a few times at say 750 rpm and for about 2/3 seconds - my sons car - the belt let go when he was pulling away from the kerb - and 5500 rpm and say 20 seconds - my friends car which blew up on the motorway at well lets say somwhat illegal speeds the results were TOTALLY different.

We popped a complete set(eight) new valves in my sons car - really only needed three and two of them were marginal they would have ground in no problem i suspect - but hardly worth not doing a complete top end overhaul when we had the head off - after that it was as good as new - the other car needed a new engine - so all in all the difference was hardly acedemic.

Flying scot...I think you are missing the point!...We are not talking about a single incident with your sons particular make of car whilst pulling away from the kerb!!..a 1.6 ford Sierra for example can break its cambelt at any engine speed and not suffer any damage.....We are talking 'Generally' and generally when a cambelt or (rarely) chain fails it is whilst driving normally on a motorway or non m/way road and as a majority of todays modern cars are 'interference' engines the 'usual' result is as i previously described....it is instant and inevitable as the event happens so fast that de-clutching or any other action by the driver will always be too late to prevent futher damage.

 

[Flying Scot]

Flying scot...I think you are missing the point!...We are not talking about a single incident with your sons particular make of car whilst pulling away from the kerb!!..a 1.6 ford Sierra for example can break its cambelt at any engine speed and not suffer any damage.....We are talking 'Generally' and generally when a cambelt or (rarely) chain fails it is whilst driving normally on a motorway or non m/way road and as a majority of todays modern cars are 'interference' engines the 'usual' result is as i previously described....it is instant and inevitable as the event happens so fast that de-clutching or any other action by the driver will always be too late to prevent futher damage.

missing what point? i did not realise that it was you that started this thread and 'owned it' and since we dont know all the details relating to the clk 230 komp with the broken cam chain that started this thread neither i or you can say under what circumstances it occured and what caused it.

I am Motor Vehicle engineer of some 40 plus years now i have seen many many cars post cam belt and chain breaks and associated components like belt and chain tennsioners failing. I outlined only two very recent incidents - at both ends of the spectrum why you would have difficuty with me posting that i find somewhat amazing. Generalisations are generally wrong and statements like the majority of todays modern cars are interference style engines is another generalisation not even remotely supported by any facts/data or even by what you wrote yourself. I know of plenty of modern cars that have non interference engines 99% Japanese so numerically the totals are very significant so i would suggest your assertion is far from accurate.

love the use of the 'royal we' NOT!!!

you respond to this thread your way - and i will respond to it my way - chill sounds about right.

 

[panason1c]

missing what point? i did not realise that it was you that started this thread and 'owned it' and since we dont know all the details relating to the clk 230 komp with the broken cam chain that started this thread neither i or you can say under what circumstances it occured and what caused it.

I am Motor Vehicle engineer of some 40 plus years now i have seen many many cars post cam belt and chain breaks and associated components like belt and chain tennsioners failing. I outlined only two very recent incidents - at both ends of the spectrum why you would have difficuty with me posting that i find somewhat amazing. Generalisations are generally wrong and statements like the majority of todays modern cars are interference style engines is another generalisation not even remotely supported by any facts/data or even by what you wrote yourself. I know of plenty of modern cars that have non interference engines 99% Japanese so numerically the totals are very significant so i would suggest your assertion is far from accurate.

love the use of the 'royal we' NOT!!!

you respond to this thread your way - and i will respond to it my way - chill sounds about right.

LoL

 

[jberks]

some cars - my Toyota for instance have non interference engines - there being no way the valves can hit the pistons even if the valve were to stick fully open the piston cant hit it a TDC dont know about a Ford CVH should be easy to find out on the Ford forum your camshaft cant stop with all valves closed not unless all the lobes fall off at the same time as the belt snaps - clever ford engineering

Yes the CVH is an interference engine, at least based on the experience of many of my fellow teenage escort drivers of the time. I knew plenty of folk who'd lost cam belts (water pump siezure was the normal cause), but I was the only one who'd got away with it. Ok, maybe intially, with no engine braking, the engine stopped instantly. That's fine, but why didn't I knacker it when the attempting to restart? I accept the all valves closed idea doesn't hold water, it would assume a cam position for 4 pots in compression at the same time, which never occurs. I figured the cam would roll back to the point of least resistance, namely where the valve springs are in the lowest compression and valve stems at their most closed position, but whether there is an ideal position I don't know.

So, as an academic excercise, why did I get away with it, yet my friends not?

 

[Flying Scot]

Yes the CVH is an interference engine, at least based on the experience of many of my fellow teenage escort drivers of the time. I knew plenty of folk who'd lost cam belts (water pump siezure was the normal cause), but I was the only one who'd got away with it. Ok, maybe intially, with no engine braking, the engine stopped instantly. That's fine, but why didn't I knacker it when the attempting to restart? I accept the all valves closed idea doesn't hold water, it would assume a cam position for 4 pots in compression at the same time, which never occurs. I figured the cam would roll back to the point of least resistance, namely where the valve springs are in the lowest compression and valve stems at their most closed position, but whether there is an ideal position I don't know.

So, as an academic excercise, why did I get away with it, yet my friends not?

well there will be no point on the camshafts rotation when one or more valve is not open for sure you cant have four cylinders on compression together they fire in sequence hence the need for a distributor cap and the more clys you have the smother the running 3 cyl one firing stroke every 120 degrees of rotation and then 6 and 12 being even better 4 and 5 are slightly out of 'natural' balance though i love the growl my 5 cyl Volvo makes while the V8 in the merc is like a turbine - needs a louder exhaust - but then my days of boy racer are over - damn blast curses

why did you get away with it and your friends not - gosh easy peasy - you obviously were good in a previous life as to your friends well lets not go there

 

[Flying Scot]

cam shaft picture

 

[Uncle Benz]

I seem to remember the CVH engine being good at wearing out cam lobes and followers. Perhaps this may explain your luck !!!!!!!!!!!!!!!!!!

 

[Uncle Benz]

No, seriously - I think the ones with the 'lean burn' head had a shaped intruder (ooo errr) on the piston, and this could clear the valves - if you were lucky. The standard head had domed pistons, and these always bent the valves.

 

[SomethingRattling]

Just my experience, I had a 1.6 Astra estate which which threw out the cam belt at around 70mph on the motorway. RAC kindly brought me and vehicle back home. I did ask the RAC chap what are the chances of bringing the vehicle back to life, 'very slim' was his reply. Curiousity got the better of me so I bought a cam belt from Halfords, only a few ££££'s, and so not to waste my time I aligned everything up and prised the new belt on, took all of 20 minutes. It ****** worked! whats more kept going for another 10k. Prior to this I believed as so did most people I asked that any engine is knacked if the cam belt/chain is lost at speed. Always worth a second look!