Guys,

I've just bought a real nice 1991 W201 2.5 Diesel with full black leather and factory Cosworth kit, in dark grey metallic ("blue black").

Its my first Mercedes-Benz after 5 VW diesels (all good, just wanted a change). I've been looking for one ever since the thread I saw a few months back about the guys out in Finland who make such an impressive job out of these W201's. I've been putting in the overtime and given it a lot of thought and I've decided I'm gonna get a 6 cylinder to put in it. I've just finished a VW Golf mk3 rebuild (TD conversion +) and this is exactly the sort of project I am looking for.

Here in the UK the multi-valve 6 cylinder can be got, but its not cheap. I rang a guy in England who runs a Mercedes-Benz breakers yard. He put a multi-valve head on a 603 but said there was somthing wrong with the way the injection pump bolted up, so the conversion never happend !

Since I cant get in contact with Muari I am hoping you guys can give me a hand. Just a few questions and I think i'll be ready to go parts finding !

1) If a Mercedes-Benz diesel engine is non turbo, does it have under-piston cooling thus making it turbo-ready ? (some VW/Audi Diesels are, nt sure about Mercedes-Benz)
2) The 2.5 5 cylinder is a 602, the 3L 6 is a 603. I know the 606 is a multi-valve version of the 603 so does this mean there is a multi-valve 2.5...605 ??
3) What type of turbo / manifold flange is used back on the 602,603 & 606 ? std T3 type?
4)Does anyone know what model of fuel injection pump they run out in Finland ? Was it an MW ?
5) Would I be right in saying that somone on this forum sent a pump to Myna Diesel in Finland for re-build ?


Any help you guys could give me would be very much appreciated.

Regards, DM

Yes, I believe the OM602 equivalent with a twin cam head is an OM605...

OM601 --> OM604 OM602 --> OM605 OM603 --> OM606

You do not want to turbo an NA engine if longterm reliability is your goal.

The stock OM602/603 uses a standard T3 flange, but I can't confirm the turbo configuration for a stock OM606. The Finns typically use a Holset HX-40 turbo, which I believe uses a T4 flange, but they also build their own headers.

I do not believe Myna can or will modify the MW pump, rather they seem to focus on the fully/partially mechanical M pumps, as found on the OM601/602/603. The M pump has a side cover, which when removed, reveals the fuel rack. Apparently, over in Europe, the OM617 engine comes with an M pump, rather than the MW we have over here in the states...don't know why.