[CEOG]

My beloved 85 300GD seems to be getting ready to give up the engine. It has a terrible loud ticking sound that doesn't sound too good. In trying to locate a replacement engine I can not seem to find a 617.931 however I have found a few 617.951s. Not being a mechanic I ask for some insight as to any significant issues that I might run into by using the 617.951 in lieu of the 617.931.

Thanks Terrance

 

[inkblotz]

Any of the OM617 engines that came out of the 300d, 300td (wagon) will work, and of course my favorite the 300 turbo diesel engine. Which is a marked performance improvement. These came out of the 300SD, 300TD (turbodiesel wagon) and 300DT. Early 80's models

Mark

 

[Hipine]

the 951 is the second generation variant of the 617A three liter turbodiesel engine. They started that series with the .950 in '79. They progressed to the 951 and then 952 during the early to mid '80s. Along the way they added stuff like an oil trap in the intake system, EGR, strengthening ribs at the rear of the oil pan, a smaller water pump pulley for better cooling, a new design of vacuum pump, higher lift cam, and probably some other stuff I'm leaving out. What I don't know is which, if any, of those things corresponded to the number changes on the motor.

I don't know what a 617.931 is. Is that the engine that came from the factory in your 300GD? A normally aspirated 3 liter diesel?

-Dave G.

 

[gwagoncar]

Good info.

The 931 engine is fitted to my 84 gd 332.

This is the basic engine no turbo.

Dave

 

[Desertstar]

617.950 = 1978-1980 W116 300sd
617.951 = 1981-1985 W126 300sd
617.952 = 1982-1985 W123 300d,300cd,300td
All turbo, mostly differences in attachment parts etc. IE: 300TD had oil pump for auto leveling system.
Mike

A quote from another forum regarding the engines:

The only differences between the OM617.95_series are so that they will work in that chassis. Like oil filter housings, oil pans, motor mounting, & ect. Every engine can have a slight variation in power due to tolerances durning assembly. Used to dyno all diesels at another dealer & found up to 5-6 REAR wheel hp differences on these engines.
A lot of 1982-83 engines USED too much oil, factory honing process was incorrect & rings never seated.
__________________
MERCEDES BENZ MASTER GUILD TECHNICIAN (6 TIMES)
ASE MASTER TECHNICIAN
27 YEARS DEALER M.B. Shopforeman
MB technical information Specialist (7 years)
190E 2.3 16V ITS SCCA racecar (sold)
1986 190e 2.3 16V 2.5 (sold)

 

[Dai]

My understanding is that the later of the series (617.95 turbos)have some important combustion chamber improvements. I think these were in the late '83 to '84 introduction timing. They run smoother with slightly more power and a lot of the lopey idle issues the five cylinders had, were smoothed out. The later '84 and '85 motors have the dreaded trap oxidizer that can disintegrate into the turbo. I believe these are in the California cars but may also be an issue in the "Federal" car motors. The later motors have the high mount turbos.

-Dai

 

[CEOG]

If I post the vin 4603317040449 could some kind soul verify the engine number?

 

[CEOG]

If I post the vin 4603317040449 could some kind soul verify the engine number?

 

[Dai]

Could you be missing one number? I tried to plug it into the Russian decoder with WDB in front of it and it won't process it because there need to be 17 digits. Is it 460332170XXXXX? Yours is only a few hundred away from mine.

If it is an '85 300GD with the origional engine then it should have a 617.931

-Dai

 

[CEOG]

The vin 46033317040449 is correct. The 17 digit is a US identifier. I went round in round with the state of Washington when I got the car titled here. Finally the state tried to use WST46033317040449, but they then accepted the original European 14 digit vin. It does have the original engine, so I thank you. I think I found a donor from a 85 sedan.

 

[alaskagwagen]

I almost hate to even bring up the topic as I am moving in the direction of SVO myself, but do you think the SVO use is implicated here? It would be interesting to get the postmortum and see what is going on.

 

[whelanrob2002]

Dai do you mean there are high and LOW mounted turboes? This is interesting as it would explain why some people think the turbo engines can't be fitted to RHD vehicles, (early, low mount turbo?), due to interference with steering shaft, while others like 4x4rancher prove it can be done, (late high mount?) and report no steering issues.Anyone got pictures of both to compare?
Bob

 

[inkblotz]

I checked my EPC and your vin shows you have a 617931 12 001368.

Mark

 

[CEOG]

The SVO had no affect on the dang engine. I will try and relay the mechanics finding on the forum today. Thank you Inkblotz for the confirmation. I also am considering putting a CDI engine in in lieu of the 617. I will post my progress. Thanks to all of you for your help. I appreciate this forum very much and read the postings daily to keep up on others events and I always learn alot.

 

[Dai]

Bob, Yes there is a high mounted turbo that is in the later '84 and '85 model year 123 and 126 chassis US cars. I don't have a photo for you but it significantly higher than the older turbo setup. I bet it would solve the RHD issues. I don't own one or I'd photograph it for you. Perhaps someone who does could shoot a picture?

CEOG, there was a digit missing in the second group of three in your first vin post. If you add WDB to the front of your vin# and plug it into the Russian decoder site I think you can get the build sheet for your vehicle. Sean at Eurotruck might have the ability to do that for you as well. When Travis was at Europa he produced one for me.

What exactly is going south with your engine? They are not that bad to rebuild usually. If the pistons are in good shape, then new sleeves, rings and a valve job will return them to service. It is also possibe to get a lot more power and torque with some upgrades to the stock not turbo but at that point a 617.95 turbo might make more sense.

-Dai

 

[warren t]

I beleive all turbos are mounted the same, but
there are two brands of turbos KKK and Garet, they
are physicaly the same exept for the position of
the waste gate, one is higher up.
Warren

 

[CEOG]

My mechanic responds, The camshaft, cam followers and valvetrain are all OK, they removed the rod caps and bearings from cylinders 1 & 2 and found the bearings to be good. There is a loud metal "clank" syncronous with the movement of a single piston (1 or 2 ) and the sound is comming from the area of the cylinder head. The injectors were removed and the prechambers examined and found to be OK, the compression is also OK. In the end they determined that a ring or part of the piston crown had broken off from lack of lubrication and is sitting on top the piston bangine into the head each time the piston comes to top dead center. So my question is should I continue to drive it, replace it or rebuild it?

 

[alaskagwagen]

Here is a 83/84 SD vs 84 300D engine from the sedan. Is one turbo lower than the other? Is it just the photo?

 

[alaskagwagen]

Wow! If the head is OK from the beating and the cylinder walls are not scored - a new piston and rings (gaskets etc) and you would be good to go. It all depends on your goal. Its a good time to justify a 617A if that is what you are looking for[]

Adam

 

[Thomas.Schumacher]

GEOG,

I would repair and drive on.

So, why was there insufficient lubrication on that cylinder? Seems to suggest that something else is going on with your engine. Oil pressure has been OK?

Is your engine running hot?

Best wishes.