Snapped timing chain - SLK 230K

[Will]

Malcolm,

You've got to break away from the old way of thinking, and look at modern costings for repairs.

It's really not a big deal in repair terms, just that it's such an in-significant engine that it's not worth any time in repairing when you can re-fit a working replacement for £1100.

Will

 

[television]

Malcolm,

You've got to break away from the old way of thinking, and look at modern costings for repairs.

It's really not a big deal in repair terms, just that it's such an in-significant engine that it's not worth any time in repairing when you can re-fit a working replacement for £1100.

Will

I know, its been said before many times. I was brought up during the war, when if you could not make your self you went without, and its stayed with me ever since.

I will do my best to change my ways, I must admit that I love my new bathroom tap that I fitted after trying to fix the old one and I am going to buy my first new computer next week. This one that I am using now cost me £3 plus a hard drive and runs at 3,3 with 1mb ram

 

[c240yaz]

And reserve isn't met either so goodness knows what the seller wants for it. Or what condition its actually in.

By the time its bought, delivered and installed, you could fix a lot of issues in the existing engine.

Which issues would you fix first ?

As it has not yet been diagnosed, as to how badly damaged the engine is, you obviously have a lot more experience than some of us, on the diagnostics of timing gear breakage, replacement parts and labour hours. I only have 32 years in the trade, so I am still learning. Apologies.

What would your estimated difference be in cost in man hours, transportation and installation of a replacement engine, compared to a teardown, parts replacement, labour hours and rebuild of existing engine ? Your experiences on this would also be advantageous on this posting.

Also, which gaskets would you recommend were changed in the rebuild process, as I am not sure about this. Please advise.
.

 

[Rob77]

Yes, very good.

I already said I'd want to find out what was wrong with the old engine first.

My comment was really in response to suggestions that the Ebay one might go for 99p, when it has a reserve that hasn't even been met. And since when did a installing a second hand engine, from a stranger on Ebay, become the default position when considering (what might be minor) repairs. It might be little better than the one she has.

I seem to have raised hairs on a hobbyhorse here but it wasn't my intention. My sincere appologies if I've given the impression that I'm a work study expert in the field of car repairs. I'm not.

 

[c240yaz]

No offence taken, and none intended, I might be a bit of an "older school mechanic" but my point is, the labour cost in this job is extreme. A straight engine job swap is the logical solution.

If Debs lived in central Scotland, although a lot of miles for me, I would volunteer my services, free, to diagnose the problem. All it would take is the removal of the rocker cover, a turn of the crank, or other, to see what was wrong.

Then, an economical solution could be suggested, even with Forum members input. Don't see why this cannot be achieved down south. I see that other members have already propositioned this in her area, and wait to see if any of the members in her area can accomodate her. After all, that's what this forum is about ?

On the subject of helping others out in your area, If anyone wants their ATF in their G/Box "Dipped" to see if their oil level is correct, rather than book your car into MB and get stung, I am willing to to do it for you, if I am in your area, ) free, no cost to you. (other than the money for fuel to get there !!)

I have the MB dipstick in the boot. Just send me a PM.

 

[Ron . B.]

Indeed, but you are supposed to have the belt changed after so many miles to catch it before it breaks!!!

Chains are supposed to live forever!!!!

Not if you a m117 engine in your car....

 

[Glenn Smith]

I forgot to mention that the mechanic said the bottom of the engine is turning but not the top so the chain must be broken!!

Not neccessarily, what this means is the drive is not being transmitted to the camshafts, leads me to ask the question has it had a front oil seal leak? has it been replaced and the crankshaft nut not tightened? this can cause the drive gear on the bottom to destroy the woodruff key and the gear would then stop turning, this would seem a more likely cause than chain breakage, unfortunatley damage to the valve gear is still going to happen

 

[television]

Not neccessarily, what this means is the drive is not being transmitted to the camshafts, leads me to ask the question has it had a front oil seal leak? has it been replaced and the crankshaft nut not tightened? this can cause the drive gear on the bottom to destroy the woodruff key and the gear would then stop turning, this would seem a more likely cause than chain breakage, unfortunatley damage to the valve gear is still going to happen

The damper on the crankshaft does share the same woodruff key
http://www.detali.ru/cat/oem_mb2.as...622716.630&CT=M&cat=68Z&SID=03&SGR=015&SGN=01

but I have never heard of the key ever being totally destroyed when the damper is loose, it still comes down to chain or camshaft snapped

 

[Glenn Smith]

The damper on the crankshaft does share the same woodruff key
http://www.detali.ru/cat/oem_mb2.asp?TP=1&F=170449&M=111%2E983&GA=722%2E616&GM=716%2E622716%2E630&CT=M&cat=68Z&SID=03&SGR=015&SGN=01

but I have never heard of the key ever being totally destroyed when the damper is loose, it still comes down to chain or camshaft snapped

Was just a thought as it is so rare for the chain to break, i have known a woodruff key on an oil pump drive shear due to a loose pulley on a peugeot, and i believe the damper pulley has a seperate key albeit on the same keyway, so it's worth just checking if it's tight, espescially if it has had a recent seal fitted.


Apologies, i see the diagram shows one key, when i changed the seal on mine it looked like a seperate key which had been fitted badly i can see from the diagram why this is now.

 

[television]

Was just a thought as it is so rare for the chain to break, i have known a woodruff key on an oil pump drive shear due to a loose pulley on a peugeot, and i believe the damper pulley has a seperate key albeit on the same keyway, so it's worth just checking if it's tight, espescially if it has had a recent seal fitted.


Apologies, i see the diagram shows one key, when i changed the seal on mine it looked like a seperate key which had been fitted badly i can see from the diagram why this is now.

I did not expect to see that long key either, until I went to the link, but as you say, could be the sprocket split, who knows

 

[Deborah]

Deborah, If you're still reading this thread give Chas a call at www.sec-shop.com He's in Kemsing not far from you.

Although He specialises in SEC's he a proper old fashioned mechanic/engineer. You'll get a straight answer and if He can't help He will be able to suggest a good independent locally that will be able to.

Hi!

Yes I am still reading this thread and my little problem seems to have caused a bit of a stir.

I would LOVE to find out how much damage has been done to my engine but unless I can find a friendly/competent mecahnic to do it for free it is going to cost me 6 hours + labour to find out. Sorry Malcolm I wish things could be the way they used to be but I'm afraid they aren't.

I could be lucky and find minimal damage so all I'm in for is some new valves, a timing chain, tensioner, gaskets etc but I may be very unlucky and find major damage and then I've wasted my money, albeit that I've found out what's wrong.

Fitting a secondhand engine that has done fewer miles could be a good move or I could be buying a bucket of bolts!!!

A recon is a definite no no unless it has come from MB themselves and they want £3k for that with £1k back for mine plus fitting!!!!!!

I will ring Chas and see what he has to say so thanks for that.

Watch this space .............. !!!

Deborah

 

[Will]

Hi Deborah,

I understand all of your concerns, but you do need to be realistic here.

No-one in their right mind would seriously pay £4K on such repairs on a 100K 10 year old SLK.

If the company (SL Pagoda?) who are offering to supply and fit an engine do the work, it must come with some sort of warranty. That's one of the advantages of using a registered company for the work.

When the costings were suggested for the work, the chain, tensioner, gaskets and a few valves, plus labour, were worked out to be as much as, if not more than this first route.

Please don't think I'm trying to be awkward but you've got to look at it this way. No matter what has caused the chain to snap, and thus the engine to run without correct valve timing, the results are going to be the same. It's going to require quite a lot of work and will cost quite a lot to fix. Your engine will be in no better state generally than before it snapped and it'll have this incident plus 105K miles of wear and tear under it's belt forever.

In an ideal world you'd say that 100% of mechanics would also re-assemble it just as well as it came from factory, but this isn't an ideal world and there's always the possibility of future trouble. Did the conrod get bent just a tiny bit, is one of the sprockets now stressed and waiting to let go later down the line, has the head been removed properly, checked for straightness and re-fitted perfectly with new head bolts torqued as per new?

I'm not anti-repairing things, I've rebuilt the top-end of my own engine only a few months ago, but that is a specialist car (Cosworth 190E) and there is no ready supply of low mileage, trouble free engines for these cars.

If I was local and had time I'd take the valve cover off to show you/see for myself roughly what's happened, but that's still not going to show you the full picture. That'll only be revealed come stripping the head and dare I say it, until it's been rebuilt and run for a while to prove the job really was a success.

Good luck

Will

 

[Bazzle]

If your lucky when they pull off the rocker cover etc they will see how easy it was and reduce the timing of the bill.

Good luck

Bazzle

 

[television]

Although Will has told me that I am out of date, with what is viable these days, it dies not change engineering principles. If the rocker cover was taken off (the first normal thing to do) the damage to the engine can be accessed.
The chain can be seen
The rocker shafts can be seen if they are intact
The shafts can be taken off, and if all of the valves go up and down easily, the only damage will be a little dent in a piston crown, and that does not matter.

I have seen engines where the belt has broken, and no other damage done.
This car was an auto, not traveling very fast.

You do not fit another engine if the timing chain was worn, so what is the difference.
If the engine is that bad, then it is not worth anyone else rebuilding it either.
I cant change my basic thoughts here and instincts

 

[Glenn Smith]

Although Will has told me that I am out of date, with what is viable these days, it dies not change engineering principles. If the rocker cover was taken off (the first normal thing to do) the damage to the engine can be accessed.
The chain can be seen
The rocker shafts can be seen if they are intact
The shafts can be taken off, and if all of the valves go up and down easily, the only damage will be a little dent in a piston crown, and that does not matter.

I have seen engines where the belt has broken, and no other damage done.
This car was an auto, not traveling very fast.

You do not fit another engine if the timing chain was worn, so what is the difference.
If the engine is that bad, then it is not worth anyone else rebuilding it either.
I cant change my basic thoughts here and instincts

I tend to agree, to a point, but any piston to valve contact should be treated cautiously, i have seen a number of belt breakages where people have put a new belt on and ran the engine and all seems fine untill a valve breaks, the hydraulic tappets are likely to suffer damage as well.

 

[Will]

Malcolm, it's an interference engine, if the timing is out, it will become damaged.

Some cars (eg Lexus LS400) can have a cambelt snap and not cause any valvetrain contact with pistons, thus not having this problem.

You cannot tell for certain exactly what damage has been caused just by removing the valve cover, sure you can see obvious stuff (broken chain) but it won't give you the full picture.

And no, this engine isn't really worth rebuilding, it's probably better for scrap.

I think there's a certain feeling that for whatever reason Deborah's likely to be ripped off, I'd say she stands a greater chance of being ripped off if she goes the rebuild route personally.

Will

 

[television]

Malcolm, it's an interference engine, if the timing is out, it will become damaged.

Some cars (eg Lexus LS400) can have a cambelt snap and not cause any valvetrain contact with pistons, thus not having this problem.

You cannot tell for certain exactly what damage has been caused just by removing the valve cover, sure you can see obvious stuff (broken chain) but it won't give you the full picture.

And no, this engine isn't really worth rebuilding, it's probably better for scrap.

I think there's a certain feeling that for whatever reason Deborah's likely to be ripped off, I'd say she stands a greater chance of being ripped off if she goes the rebuild route personally.

Will

OK not another peep out of me

 

[recycled]

just get everyone to make non interference engines like americans do.
good for 100k in between services. big and lazy , not high revving high performing european ones

 

[Will]

Sorry if my last post sounded like a rant, it wasn't intended to

Just that it seems as though we're going round in circles and Deborah's engine is no closer to being fixed either.

Deborah, best of luck with whatever route you take

Will

 

[television]

Sorry if my last post sounded like a rant, it wasn't intended to

Just that it seems as though we're going round in circles and Deborah's engine is no closer to being fixed either.

Deborah, best of luck with whatever route you take

Will

It was not a rant at all, its just forums at there best, where everyone can learn something