Why did MB design the 616/617 with a non-crossflow head? - Page 2 - PeachParts Mercedes-Benz Forum

franklynb · #16 09-08-2008, 05:17 PM

Excerpted from Paper 780633, SAE: "The Turbocharged Five-Cylinder Diesel Engine for the Mercedes-Benz 300 SD" by Kurt Oblander, Manfred Fortnagel, et al, Passenger Car Development Division, Daimler-Benz AG: June, 1978: presented at the Passenger Car Meeting, Society of Automotive Engineers, Troy MI:

Quote:

In 1936 Daimler -Benz introduced the first Diesel passenger car model 260 D with a 4-cylinder 2.6 liter engine. Today's success of the Mercedes-Benz diesel cars was founded in 1948, when the model 170 D was put into production as a fuel efficient alternative to the corresponding gasoline-powered vehicle. The next important step was the modern engine type OM 621 with overhead camshaft in the 190 D, in 1958. This engine was the basis for today's Diesel engine production program. Its last stage of development is represented by the OM 616 with its 2,4 liter displacement and a bore of 91 mm which was obtained by means of the well-proven patented cooling arrangement between the cylinders.

i think these guys would know. The "patented cooling arrangement" also goes some measure toward explaining the non-cross-flow head feature. A brief review of the water jacket diagram in the paper <30 PAGES!!! of technical FACTS> will inform, I think. It would have been quite challenging to build a cross-flow head using this cooling arrangement.

The authors also do a fabulous job of highlighting all the design changes from OM 617 to OM 617a, and their research/reasoning of same.

--frankb

Quote:

Originally Posted by TimFreeh

The OM621 was a "clean sheet of paper" design - it was state of the art thinking... in 1957.

I'm not sure why you used the smiley icon? but the engine that preceeded the OM621 was the OM636, used in the 180D.

Hatterasguy · #17 09-08-2008, 05:20 PM

Quote:

Originally Posted by ForcedInduction

The OM61x series was basically a modified version of the engines thay had been using for decades. It wasn't until the 1984 OM601 that MB made a complete redesign of the engine.

They look very similer to the old 636 I think its called in the 170D's. There roots are pre war.

Either way they got 125hp out of them, which for the early 80's was pretty damn good. GM's big V8's of the day were not putting out that much more. What was an early 80's IROC good for? 175, maybe?

Hatterasguy · #18 09-08-2008, 05:22 PM

Quote:

Originally Posted by pawoSD

And what did the OM621 descend from?

A steam engine.

leathermang · #19 02-28-2011, 05:54 PM

Even so they did not get it perfect right out of the factory..
thus if you are replacing the head gasket on a 616 or 617 you should make sure you have the latest version recommended.... I believe the difference happened around the number of number one cylinder coolant holes....