distinguishing between the two 240d engines - PeachParts Mercedes-Benz Forum

dks · #1 12-04-2003, 05:02 AM

I have been trying to find a way to disstinguish between the pre 1979 and the post 1979 240d engine.

From the web they seem to be virtually identical.

Anybody know any markings or visual differences between them?

BobK · #2 12-04-2003, 07:40 AM

I thought they all used the 616.912 engine from 1977 forward?

leathermang · #3 12-04-2003, 08:01 AM

I think there were three different horsepower ratings for the 616.

Ken300D · #4 12-04-2003, 09:46 AM

The older engines use series glow plugs, so you could check for wiring (including the zig-zag resistance wire in some places) between the glow plugs. The later engines used parallel glow plugs and had an individual wire from the glow plug relay (on the driver's fender) to each glow plug.

This is subject to an owner upgrading the series style to the parallel style.

Ken300D

R Leo · #5 12-04-2003, 10:03 AM

Quote:

Originally posted by leathermang
I think there were three different horsepower ratings for the 616.

Greg's right, there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! (this engine was installed only in 240D w/automatic transmissions)

Seriously, according to this site: http://www.geocities.com/SiliconValley/Pines/6633/w123engine.html the OM 616.912 installed in the W123s made 65hp from 1976 to mid 1979 and 72hp from mid 1979 to 1985.

I guess the only way to tell which engine you have is to look at the production date on the chassis.

#6 12-04-2003, 10:11 AM

I'm assuming you are referring to the ones as they were installed in the W115 chassis. There are numerous differences. Older 240D engines had the oil filter installed down in an (almost) impossible to reach place on the block. The series glow plugs are another difference, and they also had a pneumatic governor, and thusly a butterfly valve in the throttle similar to a gasser engine.

Stevo · #7 12-04-2003, 10:45 AM

dks

The pre "80s" engines have a 13mm bleed nut on the t-stat housing, the later ones are easier to bleed with a redesigned T -stat housing

the later 616 engines have hardened cam and rockers.

The HP between the "77" to "80" and "80" to "85" 616 engines is I believe just about the same, you could not tell the diff.

The earlier 240s used a York AC compressor, mounted on top.

dks · #8 12-04-2003, 12:11 PM

Many thanks to all.
Oh well, I was really hoping for a location of a big sticker on the engine saying its horsepower...

I have a 240d, made in 1978, registered in 79 wich was bought second? hand with a 616 engine of unknown heritage in it. I also have another engine, reconditioned which is supposed to be a 240d engine but (i have not seen it yet) apparently has the air intake coming over the top or something....

I intend to install the 2nd engine as soon as the first one goes (idling problems, smoke...great ones it gets going on a motorway, no apparent loss of power) and was trying to find out whether the 2nd engine was the most powerfull one or the original 65 Hp one.

Having run out of diesel lately, due to a faulty gauge, I know that the diesel pump on the current engine has some sort of plastic circular, white top, pump that you unscrew with your hands to pump the air out, but that migh be a later addition.

I will check for the things that were pointed out.
Again, many thanks.

leathermang · #9 12-04-2003, 12:44 PM

Well, this is from memory.. since I don't have time to find the manuals and check...
One difference was in early and later piston tops and the precombustion chamber shape to match...
Another was the cam lobe design...
Not exactly stuff you can see from the outside of the engine... as the manual also suggested " upgrading" if work was done on the old style stuff...

Stevo · #10 12-04-2003, 04:17 PM

"air intake coming over the top or something...." That would be pre "77" but how "pre" I dont know.
I bought an engine off eBay.....when I got it home and started looking at it real good, I discovered it was a auto tranny block (12 not 10 in the eng # ), the PO had installed the clutch, there is "82" stamped on the rod bearings, the head has 12mm GPs, so maybe "82" with the block. The power steering pump, air intake, motor mounts were all the pre "77". I dont know how long that basic engine was built but you could "mix and match" for a long time.

Rick Miley · #11 12-04-2003, 04:44 PM

Yeah, but did it run?

DieselAddict · #12 12-04-2003, 06:36 PM

Quote:

[i]the OM 616.912 installed in the W123s made 65hp from 1976 to mid 1979 and 72hp from mid 1979 to 1985.[/B]

The manual for my 83 240D says it's a 67 hp engine. I always thought all the W123 240D's had the same hp.

Stevo · #13 12-04-2003, 08:48 PM

Rick

"Yeah, but did it run?"

Well that remains to be seen but I think it will. The liners were bored and I have installed O/S pistons, new main and rod bearings, crank was good. The head looked good NO movement of the valves in the seats, lapped em, and installed new seals. About $650.00 into the rebuild, I am hopping it will run. Putting that engine in a Bronco or some such thing, was a project the PO had on the "back burner" for years, got married, wife gets tired of looking at junk in the garage, ....One thing that was a little odd, ALLOT of the rings were broken and really carboned up.

kerry · #14 12-04-2003, 09:55 PM

The 616 also went into many many MB vans in the 70's and 80's. I think they were rated a little higher in horsepower than the auto versions.

Stevo · #15 12-04-2003, 10:08 PM

kerry

A guy I know has a MB van with a 616 (4 spd) in it. Its really a "dog". Dont know which van but it would be nice with a 617 engine and a 4 speed. I would love to have one.

Steve