I bought a 1979 240D with 275,000 miles which apparently has a broken timing chain. The quick question is: Is it possible that the motor can be feasibly repaired by a gifted ;-) diyer? Or is the motor usually shelled after a chain breakage?
Ok now for the long story:
This is what I know to have happened and how I purchased the car. The previous owner said she was driving the car on the interstate, when the motor died on her. She tried to restart the motor, but it wouldn't. She looked under the car and noticed a puddle of oil on the road and then called her son-in-law. His roadside review was that the timing chain was broken and the head was cracked. She then gave the title to the tow truck operator on the spot. I bought it on the tow yard's auction not knowing any of this. Thinking that for 225.00 I can't get hurt to bad. The motor does not spin over, but the starter engages and doesn't turn the motor. I'm thinking the broken chain, (if that is the problem) is wedged in some tight spot. The valve cover is cracked where the chain rides. I can see the chain through the crack and it is obvious that it is not where its supposed to be. (to high, maybe even doubled upon itself) I'll will pull the cover this weekend to learn more, but I don't see where or even if the head is cracked. (the son-in-law may have meant the valve cover) It shows about 1/2 a quart low on oil. What should I expect? And any direction or advise would be appreciated.
Thanks
Rick Waltman.

First thing to do-pull the cylinder head. Have a look at the pistons, if they are shot your waisting your time (a used engine will be cheaper). I have successfully rebuilt VW diesels that broke their timing belts, not a big deal. The Mercedes uses a chain, which is not as easy to set up but not impossible, but the internal parts can be expensive. It really depends what damage occurred inside the engine. You might get away with a new chain and related parts, head gasket and valve job if your lucky, but sometimes the pistons hit so hard the wreck the main/rod bearings too.
Greg

My 300SE had its timing chain snapped while I was at 140 km/p! Fortunately it was still under the workshop warranty period, and they fixed it up for me.

All the pistons and valves were gone, and had to be replaced. Somehow, I'm just baffled how the earth could the timing chan snap when it was just replaced a couple of months ago. Anyway, from what I saw, it certainly may be a sport for a gifted DIYer, but it was certainly a lot of work involved.

Got it all fixed in 2 days at no charge.

I would expect traveling at highway speed and the chain lets go. You're looking at major damage. When the pistons and valves suddenly go free at those RPM's they just tear into one another.

Ebay it!
 

Sell the useable parts on ebay! I agree if the chain broke riding down the hwy it's probably time for complete rebuild.