Hello, I'm new to the forum, and the M-B diesel world as well. I have a '67 200D that is in need of an engine upgrade/overhaul. What I have is two clapped out, but complete OM621 engines. They were torn down when I got them, with reports of smoking badly. Upon inspection of the cyl-heads the cam/rockers/bearings look pretty beat up, and nothing measures up to spec according to the factory workshop manual that I got. I havent torn down the bottom ends yet, but the piston tops look hurtin', and the bores look a little oversized as well. Is there any common failures on these engines that I should know about? If rebuilding is not economical, what engines will bolt in with minimal or no modifications. I can handle the work of retrofitting an engine, but would rather keep it stock, or stock looking as possible. I did a search, but didn't find anything out there. If anyone knows any good sites with engine data and such, please let me know. I really want to drive this thing.

Thanks
Erik

If you want to spend some $$$, metric motors will sell you a good reman. short or long block:

http://www.mercedesengines.net/products.asp?cat=22

I've driven them for years and they are fairly durable engines, although sloooow from 0 to 60 mph. They do have a habit of getting cracks in the heads between the prechamber hole and valve seat, or otherwise out from the prechamber hole. A crack to the valve seat is bad, but other cracks are not fatal. The bottom ends are pretty rugged, though on manual transmissions the thrust surface on the crankshaft can wear and need machining. Not sure if oversize pistons are available yet, but standards are and the block can be sleeved at a machine shop (as it doesn't have sleeves from the factory) to bring it back to standard. You would want to check the condition of the prechambers for cracking or a damaged ball inside, as I have heard of and seen engines that have had the bottom of the prechamber break and fall on top of the piston. A rebuild requires a new timing chain, and a new kit for the vacuum pump is a good idea as well. New injector tips are probably a good idea too. Never heard of much of a problem with injection pumps. If these engines are maintained properly, they will run for many many miles without problems. Parts are still available, and I would get an itemized list for cost before you start, as the costs can add up quickly.

If you do want to retrofit to a new engine, I know a later 220D engine used from 1968 on will bolt right in, and I think the early 240D engines will too.

Thanks for the help guys! Looks like I'm building up the engine I have. I'm in the process of listing parts and wondering where to get them. Is anywhere good online, or should I just go through Mercedes? The heads are being sent out this week, and injectors will be cleaned and other good stuff. If I had the money, I'd buy a complete engine, but they're about 3x what I paid for the lump in the first place.

Erik

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1967 200D FINTAIL (in service)- 86K
1983 VOLVO 244 DL (daily driver)- 300K
1988 VOLVO 244 DL (ice racer) - 345K

The plans to build up the engine are looking grim now. I cleaned up the heads a little before sending them out and here's what I found.



The cracks are on all four cylinders and numbers three and four are heavily coated in oil/slime. It's a little hard to see in the picture, but between the prechamber and valve seat it's cracked, and heading out on the other side of the prechamber. The other head is also cracked, but is oily only on cylinder one. What would cause this to happen? Or is it the cracks?



Should I still bother to send these out to be pressure tested and checked over? If these engines turn out to be a boat anchors would a 240D engine from a 115 chassis bolt in? I've got a line on a complete running unit locally, and may go that route.

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1967 200D FINTAIL (in service)- 86K
1983 VOLVO 244 DL (daily driver)- 300K
1988 VOLVO 244 DL (ice racer) - 345K

I'm new here, and still fairly new to the Mercedes world. But, your project car is very similar to one I am restoring, a 1964 190D. Mine had a fatal engine death by lack of timing chain, haven't opened up the engine yet to see what it looks like, might be repairable with some valve work. I recently got a 1980 240D that was parked due to #1 rod sticking out the side of the block, and that car came with a spare 5 cyl out of a 300D, got that all swapped in and should be road ready this weekend. While I was working on this one, I got to thinking, this 240 engine has a bad bottom end, the 190 has a bad top end....hmm, will they interchange parts? I need to do some measuring with things torn down to know for sure, but at first glance it looks like it would work, other than a few cosmetic casting differences. What I also noticed that may be beneficial to your situation, is that the block casting appears to be the same in the areas of mounts and transmission facings. I would feel good about thinking it could very well work out with the 240 engine for yours, and they are plentiful on the cheap at wrecking yards in rear ended cars and such. I did notice the block bosses were a little different on the lower right front, where the alternator mounts on the 240D, nothing a newer bracket wouldn't fix.
-Chris

i have a head from a 74 240 that was gone through about 20k miles ago. it came from an engine that i had had completely gone thru and my lovely #3 daughter filled with gasonline and drove two hours scoring the cylinders and cracking the block. i believe the head is good. it will have fresh valves and guides etc.

i dont guarantee it will fit the 190 but it sounds like it will. if you are interested in it i will sell it for 200 and have it checked before shipping. you pay shipping.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.