has anyone had experience with the 603.970 engine known as the 3.5 for the 90-91 350sd and sdl in reference to rebuilding?
reading from the engine cd there is a statement that the engine has no cylinder sleeves and that it is not permissible to install sleeves.
there are no oversized pistons made for the engine,so it sure looks like they made a throw-away.
also the 603.971 was used in the 91-95 300sd,could anyone comment on that engines ability to be rebuilt?
larry perkins
stuck on 72 old cars

You can get anything sleeved....even engines that didn't have sleeves originally...the 3.5's major problem was with the rods bending not the sleeves.

__________________
Proud owner of ....
1971 280SE W108
1979 300SD W116
1983 300D W123
1975 Ironhead Sportster chopper
1987 GMC 3/4 ton 4X4 Diesel
1989 Honda Civic (Heavily modified)
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Section 609 MVAC Certified
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"He who fights with monsters might take care lest he thereby become a monster. And if you gaze for long into an abyss, the abyss gazes also into you." - Friedrich Nietzsche

but the block is at its limit and cant be bored, apparently. apparently the block would be weakened too much if bored enough to sleeve it.

in general i agree with dr bones anything can be sleeved but possibly this is an exception. in any case if my 350 has a major failure i will be getting a 3 liter 603 block to use in place of the 3.5.

__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

I am 90% sure that info is wrong I would double check that. I know my 603 has sleeves and would be shocked if they didn't sleeve the 3.5.

Unless they sell oversized pistons you need sleeves and a set of pistons to do a proper rebuild.

Metric Motors does a lot of these I would talk to them about getting a kit for this engine. But you can probably buy a brand new short block from MB for $4k or so, by the time you spend close to $3k on internal parts and some machine work on your block and crank you may just be better off buying a new bottom end.

__________________
1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

Would You Explain How You Know Your 603 Engine Has Cylinder Sleeves?
Larry Perkins

I thought the only non sleeved deisel engines were the GM 6.2 and 6.5 engines.

__________________
Proud owner of ....
1971 280SE W108
1979 300SD W116
1983 300D W123
1975 Ironhead Sportster chopper
1987 GMC 3/4 ton 4X4 Diesel
1989 Honda Civic (Heavily modified)
---------------------
Section 609 MVAC Certified
---------------------
"He who fights with monsters might take care lest he thereby become a monster. And if you gaze for long into an abyss, the abyss gazes also into you." - Friedrich Nietzsche

I know the OM621 engines from the 1960's (190Dc and 200D) did not have sleeves from the factory. I assume the earlier ones probably didn't either.

I have seen one with the head off, besides Fastlane lists them.

A2070-21022 Cylinder Sleeve Mahle IN STOCK $0.00 $49.01

I would consult with the dealer, they have a nice diagram.

__________________
1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

Were 603s particularly 603.97s used in trucks?

Sixto
95 S420
87 300SDL

most of you know i have only 3 years experience on mercedes, am learning.
i can tell you that slevees are sold for the 603.970 engine but you cant use them to resleeve a 3.5 , not enough material left after cutting out for the sleeve.
i havent rebuilt all the deisels yet but the 617 5 cyl is the last sleeved engine i have seen and i have built the 615-616-617-
my point for this thread was to see if anyone had worked out a solution to the throw away engine, other than throwing dollars at it with a new short block.
larry perkins

You could buy a 126 with a gas engine and avoid problems with the bottom end altogether.

__________________
'90 300SE 298k
-300K and it gets put into retirement.
'80 300D 255k Purchased new by family in 1980.

Had a:
1973 220 (gas)
1980 300SD
1992 400E

if it comes to that on my 350 knock on wood it seems pretty fine at present, i will find a good used short block for a 3 liter and put my rebuilt head on it. that seems a better alternative to buying a factory block at what 5000?

__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.