Has anyone ever replaced the rod bending 3.5L OM603 in the W140s with the 3.0L version that's not as prone to rod bending as the other? I read somewhere that someone took a 603 from an 86 or 87 300SDL and put it in their 90-91 350SD/SDL, so I assume the same thing can be done to the 92-93 300SD and 94-95 S350D.
-Joe

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'81 MB 300SD, '82 MB 300D Turbo (sold/RIP), '04 Lincoln Town Car Ultimate

Sooner or later every car falls apart, ours does it later!
-German Narrator in a MB Promotion Film about the then brand new W123.

I don't see why it couldn't be done--that's what I'd do. You'd have the best of both worlds; a bullet proof bottom end and a much improved cylinder head. If my '87 TD were ever to become totalled, I plan to transplant the running gear into a late model TE ('93-'95 E320) which is a stinking Vergasser--that's got to be much harder than swapping virtually identical series engines. YMMV

It would be a dog, the W140 weighs 4,700 with a 3L 603 it would have 148hp. However a turbo intercooled 606 in a W140 like the rest of the world got would be a real nice combo. Even the M104 I6 makes over 220hp, and it is just enough.

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

We were more lucky in Europe, since last of the W140 diesels were equipped with 3 litre/177 hp engines. These engines last forever with no problems as MB engines should do. You could try to import an European engine and bolt it on.

Konstruktionsbezeichnung: W 140 D 30 LA
Baumuster: 140.135
Produktionszeitraum: 06.1995 / 06.1996 - 08.1998
Motor
Arbeitsverfahren: Viertakt-Diesel (mit Vorkammereinspritzung, Abgas-Turbolader mit Ladeluftkühlung und Abgasreinigungsanlage mit Oxidationskatalysator)
Motor-Typ / -Baumuster: OM 606 D 30 LA / 606.960
Zylinderzahl / -anordnung: 6 / Reihe; 15° nach rechts geneigt
Bohrung x Hub: 87,0 x 84,0 mm
Gesamthubraum: 2996 ccm
Leistung / bei: 130 kW / 177 PS bei 4400 /min
Drehmoment / bei: 330 Nm bei 1600 - 3600 /min

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S320L -97

What would be really nice is to try to put a 606 in a 86-87/90-91 SD/SDL W126. Now, has that been tried before? Can it be done without extensive modification?
-Joe

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'81 MB 300SD, '82 MB 300D Turbo (sold/RIP), '04 Lincoln Town Car Ultimate

Sooner or later every car falls apart, ours does it later!
-German Narrator in a MB Promotion Film about the then brand new W123.

The Finns have successfully installed the OM606 in 123, 201, early 124 chassis, so a 126 should be a piece of cake. Exhaust system mods would probably be the most extensive. Keep in mind that for even less money and effort than an engine swap, an OM603 can be tweaked to produce similar or even more hp/torque than a stock OM606, so don't lose faith in those engines just yet.

Exactly my thoughts, H202.

Plus the fact, why would anyone want to substitute a mechanical IP for an electrical IP?

There is no need for replacing a 603 with a 606, unless your 603 is already needing a rebuild. Mauri replaced his 603 engine with a 606 because the 603 he had before was already tired when he had first bought it.

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1987 300SDL (324000)

1986 Porsche 951 (944 Turbo) (166000)

1978 Porsche 924 (99000)

1996 Nissan Pathfinder R50 (201000)

A 606 would probably slip into a W126 without to much work. On the intercooled models I bet the exhuast would almost bolt right up, any it come out in the same location a custom exhuast with flowmasters could be made. Their is a lot of room in the W126's engine bay the intercooler pipes and everything else should fit. I like the 606 it is an evolved 603. That electric IP delivers better fuel mileage and gas engine like winter starts. If my engine ever blows this is an option.

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200