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  #1  
Old 09-16-2011, 09:02 PM
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Question Urgent help: 1985 300D timing chain snapped when idling.

This is what my friend told me. The car was idling in the garage then heard a 'clunk' and the engine stopped. It will not turn over again. Remove valve cover and timing chain is no where to be seen - it is down inside. I have not seen the car but it is beyond me in any event.

Questions:

1) Which part of the engine could be damaged?
2) How to fish the chain out?
3) What it takes to fix it?
4) Do I need to take the head off?
5) Why the engine will not turn over? Chain jammed?

Any info is appreciated.

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Not MBZ nor A/C trained professional but a die-hard DIY and green engineer. Use the info at your own peril. Picked up 2 Infractions because of disagreements. NOW reversed.

W124 Keyless remote, PM for details. http://www.peachparts.com/shopforum/mercedes-used-parts-sale-wanted/334620-fs-w124-chasis-keyless-remote-%2450-shipped.html

1 X 2006 CDI
1 x 87 300SDL
1 x 87 300D
1 x 87 300TDT wagon
1 x 83 300D
1 x 84 190D ( 5 sp ) - All R134 converted + keyless entry.
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  #2  
Old 09-16-2011, 09:08 PM
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Quote:
Originally Posted by ah-kay View Post
Questions:

1) Which part of the engine could be damaged?
2) How to fish the chain out?
3) What it takes to fix it?
4) Do I need to take the head off?
5) Why the engine will not turn over? Chain jammed?

Any info is appreciated.
1) The cam towers and valves
2) One of those retractable claws ought to work fine. Although it could be jammed in the crank sprocket.
3) That depends on what's damaged. Clearly, you need a new chain as a minimum.
4) Only if the valves are bent.
5) The chain is likely sitting on the top of the crank sprocket. Also, the engine cannot rotate even without a chain because several valves are open. The pistons won't clear the valves and they won't close..........because you have no chain driving the camshaft.
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  #3  
Old 09-16-2011, 09:12 PM
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ouch!

was it an IWIS chain? OE? mileage?

oil pump chain may have snapped causing parts to fling into the chain...

vacuum pump may have emptied it's guts into the chain...

any valve cover damage? markings inside?

damage could be limited to chain binding on things, or it could be snapped and bent valves/cam/cam towers etc...
only way to find out is to gently wriggle crank back and forth until the chain can be fished out.
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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!
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  #4  
Old 09-16-2011, 09:15 PM
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Quote:
Originally Posted by ah-kay View Post
This is what my friend told me. The car was idling in the garage then heard a 'clunk' and the engine stopped. It will not turn over again. Remove valve cover and timing chain is no where to be seen - it is down inside. I have not seen the car but it is beyond me in any event.

Questions:

1) Which part of the engine could be damaged? Pistons crown dented possibly, cam broken, rockers broken, valve stem's bent

2) How to fish the chain out? Coat hanger, magnet, might help to remove the vacuum pump to get a better view where the chain might be

3) What it takes to fix it? New chain, tensioner, probably some or all guides at minimum. Possible crank sprocket, oil pump, cam, rockers, valves, probably not the pistons as dents are not pretty but don't effect running so much

4) Do I need to take the head off? Possibly
5) Why the engine will not turn over? Chain jammed? Yes chain is jammed, if you can get hold of an end you can sometimes gently rock the crank and lift on the chain to free things up

Any info is appreciated.
Good Luck!
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  #5  
Old 09-16-2011, 09:25 PM
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Thanks for the quick inputs.

Mileage is 280K or there about. ODO never worked since he bought the car.

1) Not sure what is an IWIS chain as engine is 'Greek' to me.

2) Is a bent valve quite obvious with the valve cover removed?

3) Would removing the oil pan help to fish the chain out or has a better idea on what is damaged underneath?

I will take a look tomorrow as a courtesy but I have no clue.
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Not MBZ nor A/C trained professional but a die-hard DIY and green engineer. Use the info at your own peril. Picked up 2 Infractions because of disagreements. NOW reversed.

W124 Keyless remote, PM for details. http://www.peachparts.com/shopforum/mercedes-used-parts-sale-wanted/334620-fs-w124-chasis-keyless-remote-%2450-shipped.html

1 X 2006 CDI
1 x 87 300SDL
1 x 87 300D
1 x 87 300TDT wagon
1 x 83 300D
1 x 84 190D ( 5 sp ) - All R134 converted + keyless entry.
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  #6  
Old 09-16-2011, 09:32 PM
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no, bent valves are nearly always imperceptible from the cam side... unless it's REALLY bent. you may be able to feel loose rockers/followers, but I doubt it.
since you were at idle, little damage may be there, still, even at idle, a diesel motor has a LOT of force.
likely the only way to know the full extent of the damage is to replace the chain, which will require REMOVING the cam to align the timing marks of the crankshaft, then installing a new chain, then performing a compression test to see if any valves are not seating...
THEN before the car will start you will have to align the IP and get it timed...
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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!
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  #7  
Old 09-16-2011, 09:34 PM
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So, do the valves have chance at damaging the pistons, or what?

Threads like this make me glad I have a new timing chain
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  #8  
Old 09-16-2011, 09:35 PM
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also, since the valves may be lightly bent, and seat fine for a compression test, but fail shortly thereafter... pulling the head may be the best choice to look for damage.
it'll make it easier to get the chain out too...
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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!
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  #9  
Old 09-16-2011, 10:21 PM
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Quote:
Originally Posted by Crazy_Nate View Post
So, do the valves have chance at damaging the pistons, or what?

Threads like this make me glad I have a new timing chain
Most of the time the damage to the piston is dents in its crown from the valves making contact. From that collision the valves and the valve train usually take the brunt of the damage. At high engine speed the damage could greater to a piston or even its connecting rod being tweeked as is from a hyro-lock occurance.

Yeah, a new timing chain is really cheap insurance for any engine over 200K and especially any engine where you really don' know the maintainence history.
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  #10  
Old 09-17-2011, 10:29 AM
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It seems to me that if you know very little about how to repair this major problem, and if your friend the owner knows even less. then it is probably time to find a good Independent service mechanic who knows these engines and have the car towed to him. However, if you want to know how to do this, and no one has any great need for this car for a long time, well then get into it. There is plenty information on this Forum to help you along, but at the least you should have a Haynes Service manual and a factory Service CD. You can find them for sale here on the Forum, (usually) and on Ebay for I would guess $75.00 for both of them including shipping. That would be the best way to start. But if the car is needed no later then sometime next week, better ship it out. Also, you need a rather complete set of mechanic tools. This is not a hammer/screwdriver type of job.
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1983 Mercedes W123 240D 4 Speed 285,000 on the road with a 617 turbo, beautiful butter yellow, license plate # 83 240D INDIANA

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  #11  
Old 09-17-2011, 11:35 AM
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Quote:
Originally Posted by junqueyardjim View Post
It seems to me that if you know very little about how to repair this major problem, and if your friend the owner knows even less. then it is probably time to find a good Independent service mechanic who knows these engines and have the car towed to him. However, if you want to know how to do this, and no one has any great need for this car for a long time, well then get into it. There is plenty information on this Forum to help you along, but at the least you should have a Haynes Service manual and a factory Service CD. You can find them for sale here on the Forum, (usually) and on Ebay for I would guess $75.00 for both of them including shipping. That would be the best way to start. But if the car is needed no later then sometime next week, better ship it out. Also, you need a rather complete set of mechanic tools. This is not a hammer/screwdriver type of job.
I have the Haynes Manual, Good tool set. I have replaced timing belt, taken gas engine head off and replaced the rings by dropping the pistons. What I have not done is diesel engine so I ask the experts. My friend is asking me to assess the damage so I promise to take a 'look'. He had it towed to a Indy but they claim they do not do diesel. This is not a DD so we can take our time and map out our options. I will see the car later today.

Thanks for the advice.
__________________
Not MBZ nor A/C trained professional but a die-hard DIY and green engineer. Use the info at your own peril. Picked up 2 Infractions because of disagreements. NOW reversed.

W124 Keyless remote, PM for details. http://www.peachparts.com/shopforum/mercedes-used-parts-sale-wanted/334620-fs-w124-chasis-keyless-remote-%2450-shipped.html

1 X 2006 CDI
1 x 87 300SDL
1 x 87 300D
1 x 87 300TDT wagon
1 x 83 300D
1 x 84 190D ( 5 sp ) - All R134 converted + keyless entry.
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  #12  
Old 09-17-2011, 11:50 AM
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Isn't pulling the front cover a given? In the unlikely event you fish out both ends of the chain and its still engaged to everything below the head gasket, wouldn't you want to look around for the cause or collateral damage? Can you see the oil pump chain with the lower pan removed?

Sixto
87 300D
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  #13  
Old 09-17-2011, 12:49 PM
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Drop the lower Oil Pan and look for pieces of Metal.

MY Question on Timing Chain Failure
Who has or knows someone that has experienced a timing chain breakage/failure?

Who has or knows someone that has experienced a timing chain breakage/failure?
Who has or knows someone that has experienced a timing chain breakage/failure?

What in particular causes vacuum pump failure?
What in particular causes vacuum pump failure?


New Vacuum Pump Ruined due to too much Timer Shaft End Play (the title from my notes).
second vacuum pump, help! on a trip-Toronto
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  #14  
Old 09-17-2011, 01:02 PM
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I would suggest pulling the cam and allowing all valves to close, then run a leak down test and see if the valves are sealing or not, after visually determining that nothing is too badly amiss with the valves after taking off the cam cover.
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..I also have a 427 Cobra replica with an aluminum chassis.
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  #15  
Old 09-17-2011, 01:59 PM
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Ive got an 85 CA motor in Dallas area with a blown headgasket-if you got a pickup. Has to be r-n r'd for that , But would be much cheaper, especially if the smog goons wont let you put in an earlier engine there.


Last edited by panZZer; 09-17-2011 at 02:12 PM.
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