M-B IDI Diesel Engines - what was available through the years

Discussion in 'Mercedes Benz Diesels' started by The Warden, Oct 12, 2005.

  1. The Warden

    The Warden MiB Impersonator Supporting Member

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    This thread is intended to complement the “M-B Chassis” thread. To try and make the “Chassis” thread somewhat less confusing, I’m referring to the engine model numbers listed in here when describing what engines were available in a specific chassis. I figured that it'd be better to break this up into two threads than to try and make one monster post. I know that this is a lot of information and can seem very confusing; if anyone has a better suggestion on how to present it, I’m all ears. :)

    First, all M-B engines have a 6-digit model number, similar to the chassis number. The first three digits indicate what "basic" engine it is, with the last three digits indicating what "version" of the engine it is (i.e. is the engine turbocharged, does it have an EGR setup, etc). The model number on an M-B gas engine begins with the letter M ("motor", I think), while the model number on an M-B diesel engine begins with the letters OM ("oel motor"; basically, "oilburner ;)). I'm limiting this to diesel engines, since I know jack-squat about the gas engines...and I'm going to try and keep this chronological. Again, these are only engines as seen in U.S. models; European models ARE different (for instance, the OM616.912 was only sold in the U.S. until 1983, but was sold until 1985 in Europe). On that same note, keep in mind that there are Euro-market cars floating around in the U.S. that, due to having been originally sold in Europe, may not conform to this list. If you come across a car that does not match anything in this list, you are almost certainly looking at a Euro-market car. Furthermore, I opted to not include the new Common-Rail Direct-Injected engines (CDI's) that are available today, due to a lack of readily available information.

    The following are cast-iron block, cast-iron head indirect-injected (IDI) engines. All are single overhead camshaft engines, with a timing chain connecting the crankshaft to the camshaft and to the injector pump drive gear. All have the OHC equivelant of solid lifters, requiring a valve adjustment performed every 15K miles. The OM61x engines listed below are the most common engines you will see in a U.S. M-B diesel, and did a lot to solidify the reputation M-B diesel engines have of lasting forever.
    OM636.930 - 1.8l (I think) inline-4 n/a, used between 1953 and 1961. The OM636 and the OM621's are likely the same basic engine block, and are unique compared to other engines.
    OM621.910 – 1.9l (I think) inline-4 n/a, used between 1958 and 1961.
    OM621.914 - 1.8l (again, I think) inline-4 n/a, used between 1961 and 1962.
    OM621.912 - 1.9l inline-4 n/a, 60hp, used between 1962 and 1965.
    OM621.918 - 2.0l inline-4 n/a, 60hp, used between 1966 and 1967.
    OM615.913 - 2.0l inline-4 n/a, 61hp, unknown age span. The OM615, OM616, and OM617 share a basic block design and construction (although there were many changes, including adding a cylinder in the OM617).
    OM615.912 - 2.2l inline-4 n/a, 60hp, used between 1968 and 1973.
    OM616.916 - 2.4l inline-4 n/a, (probably) 67hp, used between 1973 and 1976.
    OM617.910 - 3.0l inline-5 n/a, (probably) about 90hp, used between 1975 and 1976.
    OM616.912 - 2.4l inline-4 n/a, 67hp, used between 1977 and 1983. Oil filter relocated as compared to 616.916, due to different chassis design.
    OM617.912 - 3.0l inline-5 n/a, about 90hp, used between 1977 and 1981. Oil filter relocated as compared to 617.910, due to different chassis design.
    OM617.950 - 3.0l inline-5 turbocharged, (probably) 120hp, used between 1978 and 1980. Note that this is the only turbocharged 617 that did NOT have factory EGR equipment, at least as sold in the U.S.
    OM617.951 - 3.0l inline-5 turbocharged, 120hp, used between 1981 and 1985. EGR equipment added.
    OM617.952 - 3.0l inline-5 turbocharged, 120hp, used between 1981 and 1985. Believed to be identical to 617.951, except for minor differences to accomodate a different chassis.

    The following are cast-iron block, aluminum head indirect-injected (IDI) engines. Like the cast-iron engines, a timing chain connects a single overhead cam (except for the OM606, which has twin overhead cams and 4 valves per cylinder) and the injector pump drive gear to the crankshaft, but the OHC version of hydraulic lifters are used, eliminating the need for periodic valve adjustments. Some later engines have electronic controls for the EGR, and possibly for pump timing as well. All of the following engines share a basic block design and construction, although like the OM61x engines there were many changes. These engines share very little with prior designs.

    OM601.921 - 2.2l inline-4 n/a, 72hp, used between 1984 and 1986.
    OM603.961 - 3.0l inline-6 turbocharged, 148hp, used between 1986 and 1987.
    OM603.960 - 3.0l inline-6 turbocharged, (probably) 148hp, used in 1987.
    OM602.911 - 2.5l inline-5 n/a, 93hp, used between 1987 and 1989.
    OM602.961 - 2.5l inline-5 turbocharged, 123hp, used in 1987.
    OM602.962 - 2.5l inline-5 turbocharged, (probably) 123hp, used between 1990 and 1993. Believed to be identical to 602.961 except for minor differences to accomodate a different chassis.
    *OM603.970 - 3.5l inline-6 turbocharged, 134hp, used between 1990 and 1991.
    *OM603.971 - 3.5l inline-6 turbocharged, 148hp, used between 1992 and 1994.
    OM606.910 - 3.0l inline-6 n/a, 134hp, used in 1995
    OM606.912 - 3.0l inline-6 n/a, 134hp, used in 1997. Believed to be identical to 606.910 except for minor differences to accomodate a different chassis.
    OM606.962 - 3.0l inline-6 turbocharged, 174hp, used between 1998 and 1999.

    I hope this helps :) Please also reference this webpage. Link is now dead, but still available through Archive.org; take a look here.

    *WARNING FOR THIS ENGINE: There was a defect in the building of many of these 3.5l engines. The connecting rods were cast incorrectly, making them weaker than usual. As the rods begin to fail, they typically make the piston move about in the bore, ovaling out the cylinder to the point where the cylinders can no longer hold compression. For whatever reason, I don't believe simply re-sleeving the cylinders will correct this, so this can only be repaired by replacing the entire shortblock. I believe that some later engines were built with the correct rods after M-B realized that they had this problem, and many cars out there have already had the blocks replaced. But, I do not know of an external method of determining whether the engien has the old or the new connecting rods, so BEWARE when looking at any car powered by one of these engines. This problem is limited to the OM603.97x 3.5l engines.
     
    Last edited: Jan 1, 2011
  2. milner351

    milner351 Full Access Member

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    Thanks for posting this!

    What would you recommend for a service manual for a '96 606.910 engine? I've not had good luck finding anything that goes into detail about determining timing chain stretch or explaining how to change the timing chain.

    :eek: I'm nervous about the chain as the engine has 262k on it, and I have no prior record showing timing chain replacement.
     
  3. Desert Dually

    Desert Dually cane corso

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    Warden, thanks for the excellent and informative write-up on the M-B diesels. I am trying to learn as much as possible about them. Hoping to pick one up someday, just to have something to tinker with. :thumbsup:;Sweet:cool
     
  4. AzTraveller

    AzTraveller Registered User

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    Warden, Great info.
    I'm looking for an MB engine for a swap, however, I need physical specs on the engines. I have "ONLY" 22" to fit the engine into, front (pulley) to back (flywheel). I'd prefer a turbo'd engine, but again, don't know which would meet my limited space. Around 120HP, or more, would be preferred.

    Any recommendations? :dunno
     
  5. towcat

    towcat Administrator Staff Member

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    22" won't allow you to put in any MBZ motor.
    you might want to take a look at a VW diesel....
     
  6. AzTraveller

    AzTraveller Registered User

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    Not even a 4cyl MB engine ? :dunno
     
  7. The Warden

    The Warden MiB Impersonator Supporting Member

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    It MIGHT be possible, but I don't know. I don't have the measurements for a 4 cylinder engine...and bad news is, there wasn't a turbo 4 cylinder sold in the U.S. market, and no 4 cylinder M-B diesel put out nearly the horsepower you're looking for.

    I tend to agree with towcat; you'd probably be better served with a VW engine...and, for that sort of horsepower, you'd probably be best off with a newer TDI. It's doable, but quite a project.

    What are you planning to put the engine into?

    Would love to hear more about it...good luck! ;Sweet
     
  8. dozer

    dozer Full Access Member

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    Warden, thanks a lot for taking the time to type all that up......very useful, and I've already copied it to my MB 'notes' file.....and emailed it to my buddy too.... ;Sweet

    ps; I too would be very interested in a listing of physical dimensions and weights for each block/displacement/configuration.

    Especially a table which included clutch, spline, shaft, and other such dimensions. Also, I'd love to find a known-precise/accurate CAD drawing of the block bolt-pattern, to build G-code files from.

    I don't drive any MB's any more (had a 300SD and 300TD in prior years), but I do use the engines as replacement for gassers in mining and ranching equipment; as well as mini-truck conversions.

    pps; that link you included....

    http://home.hiwaay.net/~gbf/mbmodels.html

    is a 404 now.....fyi....

    thanks again for your post Warden
     
  9. The Warden

    The Warden MiB Impersonator Supporting Member

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    I'm glad it was useful :) and I'd love to find something giving block dimensions and weights as well...the moment I come across something like that, I'll put it on here :) I wanted to swap an OM616 into an '80's Toyota pickup a few years ago, but didn't have the $$ or the resources....and, even if I had had that, trying to get it titled would have been a cast-iron bear, eh?

    Shame that that site died...it was my basis for much of the information I posted in this and the other thread (particularly on the older models)...I did find it via archive.org; the link via that site is http://web.archive.org/web/20080214224212/http://home.hiwaay.net/~gbf/mbmodels.html
     
  10. trev0006

    trev0006 Dunce

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    Yes, Thank you for posting. Very useful information.




     
  11. Boston

    Boston Full Access Member

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    I found a 1978 Mercedes 300cd for sale dirt cheap
    thinking of converting it to run on WMO and was just wondering if this is a likely candidate
    IE I seem to remember this engine being a good one for conversion but just thought I'd ask

    thanks
    B
     
  12. The Warden

    The Warden MiB Impersonator Supporting Member

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    The 61x engines are excellent candidates for WVO conversions; I imagine they'd be fine with WMO but I'm not aware of anyone who's tried (which doesn't mean that no one's tried, just that I don't know about it ;) ). Biggest concerns with that car will be the climate control system (which is an early design abandoned by M-B in 1981 and is VERY prone to failure) and the rear window regulators (which are unique to the coupe and IIRC tend to be troublesome). I would suggest spending some quality time on this site: http://unwiredtools.com/accii.asp ...it offers a replacement for the heater servo that will make your life easier AND is likely far less expensive than the factory servo :shocked:

    Hope that helps some...good luck!!
     
  13. itsacrazyasian

    itsacrazyasian residentcrazyasian

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    The unwired setup is nice and much much cheaper than the retarded oem MB setup. Hardest part is mounting the box. I installed one in a customers 500 sl fairly recently.

    BTW the OM617 loves WMO.

    Heres my half million mile 1983 300SD cold starting in 35F last week on 50% WMO/30% waste tranny/20% #2
    [​IMG]
     
  14. Boston

    Boston Full Access Member

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    thanks
    as it turns out when I went to go look at the car it didn't seem worth it
    they guy had parked it for five years without making any preparations for long term storage. Then when I showed up he was trying to crank it over, and over, and over, and over. Miraculously he hadn't killed the starter but when I asked him if he soaked it in oil for a few days before trying to roll it over he said; huh, did I do what, why. Then I noticed the can of either.

    I passed on the car
    cant imagine dry starting a vehicle after five years of being parked wouldn't break a few rings so I decided to let it go to the next guy
    I wasn't looking for a complete breakdown I just wanted to tinker and go.
    oh well
    thanks for the advice

    B
     
  15. The Warden

    The Warden MiB Impersonator Supporting Member

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    Sounds like you made the right decision...yikes!! Best of luck to the poor guy who ends up with that car! :(
     

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