Pinpointing the OM evolution: 617->603 ->606 - PeachParts Mercedes-Benz Forum

Rashakor · #1 08-29-2006, 07:56 PM

For a while now I am trying to determine what are the details and advancements that have graced the light duty diesel from Daimler over the the 80's and the 90's.
Now, I would the great people from this forum to start a connaisseur/scientific discussion about what design detail makes a OM603 and by extension a OM606 better mills than a OM617.

For example as a starter:
What are the advantage brought by the aluminum head, besides what it obvious (weight!)... Why it produced more power? Why the 603 or 606 can be turboboosted way beyond what a 617 can?

#2 08-29-2006, 08:32 PM

The OM606 is basicly an OM603 with a 24 valve cylinder head.

Hatterasguy · #3 08-29-2006, 08:39 PM

I don't know why MB went to an aluminum head. Just that all modern MB diesels seem to have gone to this. I suspect it has to do with heat transfer.

The 603 and later 606 are similer engines. The 606 has a great head design. 24 valves, 2 cams, with the injector in the center of the valves.

IMHO the 606 is the best diesel MB has imported to this country, but I don't have any time with the new ones yet so this may have changed.
They get great mileage, are quite, have tons of power, and last forever. What more could be asked?

TimFreeh · #4 08-29-2006, 08:48 PM

Quote:

Originally Posted by Hatterasguy

...... What more could be asked?

Well I guess I'll start the list.

1) I'd like to have a better than 50% chance of changing the glowplugs without removing the cylinder head.

Hatterasguy · #5 08-29-2006, 08:54 PM

Well if the glow plugs were removed and the holes reamed once a year there probably wouldn't be a problem. Considering how simple it is to get at the glow plugs on a turbo charged 606, this is pretty simple.

But yes this is a bit of a down side. But what can you do nothing is perfect.

Rashakor · #6 08-29-2006, 09:05 PM

Quote:

Originally Posted by Hatterasguy

I don't know why MB went to an aluminum head. Just that all modern MB diesels seem to have gone to this. I suspect it has to do with heat transfer.

Ok that is a good start... why is that good for heat transfer? AL retains less heat than iron? How is the cooling system different from a 617 and a 603?

t walgamuth · #7 08-29-2006, 09:14 PM

i think the al head was purely to save weight. the six cyl engine is inherently a heavier design than the five. and more smoothness was apparently desired hence the six cylinder design.

tom w

Rashakor · #8 08-29-2006, 09:21 PM

so then why it produces dramtically more power than the 5 cylinder?
Why the finns can get 300Hp from a 3Liter 603? and not do at least 5/6 of that in a 617? why is there the concern that the 617 will melt?
Also what were the changes introduced in the 603 to increase efficiency (more valves?)

TheDon · #9 08-29-2006, 09:33 PM

the 617 is inherently flawed, not having a cross flow head is limiting

#10 08-29-2006, 09:58 PM

You have to remember that the 617 is basically the same design as a 616, 615, etc. These are 1960s designs, not 1980s designs. Comparing a 61x to a 60x is like comparing a 60x to a CDI. Even though, I'll stick with the 61x.

Dana B. · #11 08-29-2006, 10:19 PM

Don't forget the 602.

TheDon · #12 08-29-2006, 10:23 PM

Quote:

Originally Posted by Craig

You have to remember that the 617 is basically the same design as a 616, 615, etc. These are 1960s designs, not 1980s designs. Comparing a 61x to a 60x is like comparing a 60x to a CDI. Even though, I'll stick with the 61x.

id kill for a 603 SDL.. not the 350 but the 300..

t walgamuth · #13 08-29-2006, 10:25 PM

Quote:

Originally Posted by TheDon

the 617 is inherently flawed, not having a cross flow head is limiting

this is obviously a big part of it.

tom w

TheDon · #14 08-29-2006, 10:27 PM

yep it is... not only do you have such a small spot for the routing of tubing for an intercooled system youve got thermodynamics or something like that.. i know its alot better for the air to come in one side and the exhaust out the less... more efficient

Hatterasguy · #15 08-29-2006, 11:09 PM

Quote:

Originally Posted by Rashakor

so then why it produces dramtically more power than the 5 cylinder?
Why the finns can get 300Hp from a 3Liter 603? and not do at least 5/6 of that in a 617? why is there the concern that the 617 will melt?
Also what were the changes introduced in the 603 to increase efficiency (more valves?)

The 603 and 606 have better head designs and are able to push more power as a result. The 606 is the best in this regard and they have pushed them to 500hp. It has twice as many valves so much more air can flow.

The 617 is not able to produce these numbers, due too its design.