Differences 1977 300D Engine US vs. UK/Euro
 

I am comparing 1977 300D, W123 diesel engines 617.912 type (one a US model and the other a UK/Euro model) and want to know if anyone knows about differences between the two engines? I have looked at the engines from the outside and they look the same, for example: engine mounts, York AC mount/bracket, alternator bracket mount/bracket, power steering mount/bracket, etc. etc. The official M-B engine manual also shows no differences (other than the need to retorque the head after R&R'ing the head gasket for some versions), but the M-B manuals have been wrong before. I am also looking at the flywheel (both are auto trans), flywheel mounting bolts/pattern, starter mount/bolt pattern, bellhousing mount/pattern, etc., etc. The internal components also look the same according to the M-B manual (crank, rods, pistons, cam, rockers, etc., etc.), but I have not actually compared them since the UK/Euro engine is still assembled (I did remove the valve cover and everything looks the same, but I did not use a micrometer to measure and compare components).

From the info I have and my visual inspection, both engines look the same. However, my knowledge is not perfect and would appreciate any info from more knowledgeable members/moderators.

Thanks,
Tom

You will possibly find some minor differences in the sensors and possibly an EGR valve on the US engine. The guts of the engine will be the same including bellhousing pattern, etc. On any engine the pilot bearing area is different from manual to automatic.

The only significant difference is the injection pump. Euro models have a Bosch and US models have an American Bosch. The pumps themselves can be interchanged among engines, but the parts for the pumps will not necessarily interchange.

Good luck,

Larry:

Thanks for the info!

Both engines are mated to an auto trans, so the pilot bearing area should be the same. The flywheel for the auto trans is supposed to be the same for all 615, 616, and 617 engines; the flywheel for the 617 manual trans is heavier (width is 90mm) than the 615 & 616 (74mm width) according to the M-B manual.

Are you aware if the UK/Euro Bosch early IP had the same problem as the Am. Bosch 617 IP? I have come across some info about the copper sealing ring leaking for the individual injection pump element causing problems - the IP tries to create two columns at once. Seems M-B had to redesign the copper sealing ring two times before fixing the problem.

Tom