According to Wikipedia, the 3005cc engine is the 617.910, 617.912 (installed in the early non-turbo W123 300D's) and 617.950 (installed in the early W116 300SD with turbo).

The 2998cc version is the 617.951 and 617.952.

The 617.951 was in the first Turbo W123 wagons. The 952 went in to the 1982 and later turbo diesels.

So just check the engine number.

 

Thanks, I didn't remember to check the engine number
Beside that, is there anything else that will tell you if it's an 2998cc or 3005cc? Or are they exactly the same on the outside?

 

Well, now I'm confused. My car's registration says that the car is from 1984, I always thought this was incorrect because it's a 1st series. A few months ago I contacted Mercedes-Benz Classic in Germany that confirmed me that the manufacturing year of the car was 1979, which made sense since it's a 1st series. But now I checked the engine number and it's a 617 912 which means it has to be before August 1978.
Is it possible that in the factory they installed an engine made before August 1978 on a chassis made in 1979?

 

Have you confirmed your engine is the original to your vehicle? You can check the engine number and compare this against the VIN.

If they match then it's possible the car was manufactured late in 1978 so it could have a 1978 engine but the model year was 1979.

 

This is what I found on wikipedia:

"The OM617.910 was a 3.0 L (3005 cc) engine. Power output was 80 hp (59 kW)@4000rpm. It was first used in the W115 chassis. The engine was left unchanged in 1977, when the W115 was replaced by the W123. An upgraded version, the OM617.912, was introduced in 1979 rated at 88 hp (65 kW) at 4400 rpm."

If I understand this correctly this means that:
- OM617.910 = 3005cc with 80hp
- OM617.912 = 2998cc with 88hp

Is that it?

 

I don't see in that Wikipedia article that it says the 617.910 and 912 are different displacement.

However you are correct that the 912 has a bit more power.

Have you checked the engine number on YOUR engine? Then you'll know which one it is.

They are going to look the same on the outside, when it comes to the general design of the engine. There are other differences between years that can help narrow it down, like whether the transmission is vacuum or rod controlled, for example. And of course the later ones you can tell because they have a turbo.

 

Yes, I checked the number on my engine, it's a 617.912.
What I'm trying to do is to figure out the displacement and horsepower of my engine.

Wikipedia doesn't say that the displacement changed with the 617.912, but wiki mercedes-benz-classic says that the 2998cc came in August 1978 and the 88hp version in September 1979. So, if the 617.912 has 88hp like wikipedia says, it has to be a 2998cc because the 2998cc engine appeared 1 year before the upgrade to 88hp.
First they changed from 3005cc to 2998cc in 1978 and later in 1979 they upgraded it (the 2998cc) to 88hp.

Right?

W123-300D-Motor/en ? Mercedes-Benz Classic Wiki - Online-Lexikon rund um Mercedes-Benz Oldtimer

 

The most noticeable external difference on a stock (so long as someone hasn't changed them!) engine is the glow plugs. The early type have the wire connections between them that gets hot. In the engine itself you have different pistons and different pre-chambers

Chapter 05-117 in the FSM shows the difference between the old and new internals

There's some spec information here

W123-300D-Motor/en ? Mercedes-Benz Classic Wiki - Online-Lexikon rund um Mercedes-Benz Oldtimer

(that doesn't help much)

 

That's the same link I posted earlier. I do have the older glow plugs version on my engine but if it is a 2998cc that doesn't make any sense.

 

The engines made from Dec 1979 should all have the reduced capacity and increased outputs. Check the block for casting date.

 

The engines made from Dec 1980 should all have the reduced capacity and increased outputs. Check the block for casting date.

The numbers on the block are: 617 011 09 01 and 15 F 79. I'm assuming that the 79 is the year. And the engine number is 617 912 12 080 898.

 

I found this info on another forum:

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, 62hp, used between 1973 and 1976.
OM617.910 - 3.0l inline-5 n/a, 88hp, 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, 88hp, 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, 110hp, used between 1978 and 1980. Note that this is the only turbocharged 617 that did NOT have factory EGR equipment until mid 1980 production.
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 accommodate the W123 chassis.


According to this my engine as 88hp so I'm assuming it's a 1979 OM617.912 - 2998cc 88hp.

Right?

 

I found this info on another forum:

OM617.912 - 3.0l inline-5 n/a, 88hp, used between 1977 and 1981. Oil filter relocated as compared to 617.910, due to different chassis design.

According to this my engine as 88hp so I'm assuming it's a 1979 OM617.912 - 2998cc 88hp.

Right?

Apparently the upgraded outputs began in August 1978.

And the N/A 300D was available in most countries until the end of the W123's production. We received the increased output engines here in South Africa starting 1980.

So yours may well be the "new, improved" OM617 (June 1979).

 

I read again the info I just posted and it says that the 617.910 has 88hp which is incorrect so I'm doubting the reliability of this info now.

 

How about the 617.953?

 

What's about the 617.953?

 

That's what I have. Didn't see it on the list.

 

It's not a complete list of all the different engines, it's just a part of a post that I found on another forum and copy/past here.

 

Chapter 00-010 in ye olde FSM also says the improved power output started in 1979 - so I think you have the more modern higher output lower cubic capacity engine

It is a shame Govert isn't about any more - the book worm of old would have known where to find that kind of information.

 

- so I think you have the more modern higher output lower cubic capacity engine

That's what I think too but not 100% sure. I never thought it would be so difficult to find out the displacement and hp of a Mercedes-Benz engine

 

617.912:

59 kW - up to August 1979
65 kW - from September 1979 (from engine nr. 617912 12/52/22/62 085946 (and some other), 617912 12/52/22/62 085209, for 123.190 from engine nr. 617912 10/50/20/60 095217 (and some other))

3.005 cc - up to August 1978 (up to engine nr. 617912 10/50/20/60 056044, 617912 12/52/22/62 053945)
2.998 cc - form August 1978 (from engine nr. 617912 10/50/20/60 056045, 617912 12/52/22/62 053946 and from engine nr. (65 kW) 617912 12/52/22/62 085946 (and some other), 617912 12/52/22/62 085209, for 123.190 from engine nr. 617912 10/50/20/60 095217 (and some other))

So post the engine number, and I'll try to determine version of the motor.


Ciao!

 

So post the engine naumber, and I'll try to determine version of the motor.

That's the 3rd time I post my engine number in this thread here it is:

617 912 12 080 898.

If I understand it correctly my engine is in fact a 2998cc with 88hp

3.005 cc - up to August 1978 (up to engine nr. 617912 10/50/20/60 056044, 617912 12/52/22/62 053945)
2.998 cc - form August 1978 (from engine nr. 617912 10/50/20/60 056045, 617912 12/52/22/62 053946 and from engine nr. (65 kW) 617912 12/52/22/62 085946 (and some other), 617912 12/52/22/62 085209, for 123.190 from engine nr. 617912 10/50/20/60 095217 (and some other))

 

OK. So now what?

 

So now that. OK?

 

Cheers :thumbsup:

 

:thumbsup:

And thank you all for all the help