Can anyone I.D this engine?
 

I have a 79 300cd. I suspect the engine is not original,1 It has a transmission vaccume valve mounted on the IP (not hooked to anything) but my transmission doesnt have a modulator valve. 2 it takes the pencil type glow plugs. This makes me think that it must have a newer then 79 engine,but it does not have an egr valve! can anyone tell me what year this engine is by these numbers?or point me somewhere to look them up? 617 912 12 105 499
P.s this is the BEST website ever! I have learned more here in 3 hrs then in 3 weeks searching the other mercedes sites!

That would be a 617.912- it is the right engine for your car. The 300D and 300CD had it through 1981, I believe, and the TD through 1980.

Could be the transmission is not OE.

Could also just have had an Injection pump from a different engine that utilized the VCV on the IP.

Pencil glow plugs did not come out until the 1980 model year, and I think the early 1980 models still had the loop style. The early transmissions did not use the vacuum valve, but mechanical linkages. Not sure when exactly they went to vacuum. The 617 912 12 ###### is correct for a W123 non-turbo car with an automatic transmission (12) from 1977 to 1981, but the 105499 sounds like a 1980 or 1981 engine. Probably a California engine given the EGR valve. I suspect you're right about the engine being changed.

I've got a 79SD with an OE engine and pencil plugs (not the retrofitted pencil plugs). It also has vacuum control to transmission.

correct, 1979 300SD's had the newer pencil type plugs, possibly 78's did too but i havent seen one to confirm this, could be that just the turbo models had this and the non turbos had the loop. by 1980, they were all pencil.

johnhef,

I have a '78 300SD. It has the pencil GP. I think all the 300SD engines (which strarted in 1978) have pencil GP.

P E H

For clarification, I was referring to the OM617.912 engine which dieselfumes has. The 300SD had the OM617.950 and 951 engines which very well could have had the new style glow plugs and vacuum controls earlier, as they were the top of the line diesels.

I have a '78, '79 and '80 300SD and they all have parallel (pencil) GP and the vacuum valve on the IP that controls the vacuum to the transmission.

P E H

yes, we have established that the SD 116 and 126 Mercedes diesels all came with Parallel pencil plugs. this question is about a NON TURBO 123 300 D
in 79 it should NOT have come with Pencil plugs. in 80 it would have had pencils, if it was a late build.

OP, I bet either the head or the entire motor was swapped from a newer car. enjoy it.