Ok i know the turbo 617 is around 425 new from the factory now whats the non turbo 617A rated at? i know the bore from 1976-1985 changed along the way from 3007cc or so to 2998cc so whats the comprsssion difference?

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Wie lange wird Ihr Auto leben?

The compression is about the same for both, 21.5 to 1 I believe.

Tom W

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[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.

The factory's "Technical Data/Passenger Cars" (April 1985 Edition) on page 106 gives the compression ratio as 21.5 to 22 for all diesel engines.

__________________

"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

The turbo engines have a 0.5:1 higher compression ratio.

Um i was asking in psi sorry i didnt clear that up.

425psi on each cyclinder is basically new for a turbo 617.......what is it for a non turbo?

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Wie lange wird Ihr Auto leben?

I thought 450 PSI was new... approx 30Bar...

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

615, 616, and 617 engines have compression 21.5:1
601, 602, 603 engines have compression 22:1

regardless of NA or turbo.

There is no compression difference between, for example 617.912 (NA, 88 HP) and 617.952 (Turbo, 125 HP), according to the Technical Data manual referenced in my earlier post.

Jeremy

__________________

"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

That is false.

OM61x.91x is 21:1
OM617.95x is 21.5:1

Attached Thumbnails

   

So the psi in each cyclinder is the same as for non turbo and turbo ...i always thought the non turbo was higher.

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Wie lange wird Ihr Auto leben?

Forced, please identify your source.

My source (see attached photos) is "Technical Data/Passenger Cars," April 1985 edition. The version that I have is a USA reprint (c) 1990 Mercedes-Benz of North America and Mercedes-Benz of Canada, part #2364. It covers models 107, 123, 124, 126, and 201 and includes (for us diesel-heads) engines 615, 616, 617, 601, 602, and 603.

Jeremy

Attached Thumbnails

   

__________________

"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

Mercedes service manual. page 030/1

Yours is probably another error in the translation. The manual also says the 116 300Sd has a 170hp om617 when we all know it does not.

MY service manual dated 1987 says that, as much as I hate to admit this, that Forced is correct. 617.912 is 21.0 and 617.952 is 21.5

Don't know why you need to know the psi when factory new but generally you check psi between cylinders to see if there is excess wear in one cylinder and don't pay much attention to the number only the difference.

__________________
1977 300D Lost coolant while someone else was driving
1983 300D Can't run without oil
1985 300SD (gone but not forgotten)
1990 300TE 4matic Sold
1991 Yamaha Venture
1975 Kawsaki 250 triple
1974 Honda 200CL
1951 8N Ford
2008 Wildfire 650C

What's a half a compression point amongst friends?

He did ask for EXACT numbers though.

Tom W

__________________
[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.

Just bought a compression tester, so I'll join the discussion by asking..

What psi/bar-ranges would indicate major trouble? What is normal readings?
I have two 617's (.910 & .912) and a 616.934, they're well worn all three of them. At what point should I know on the gauge glass and mumble "uh oh"?

Valves are adjusted on all of them.

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Tomas, Sweden
1966 Mercedes Benz 230S with OM617.912, automatic. Disk brakes from W108
1983 Mercedes Benz 300TD grey, OM617.912 and 5-speed manual
1983 Mercedes Benz 300TD blue 7-seater, OM617.912 and 5-speed manual

My opinion FWIW is that you want to look for at least 300 psi and the readings should all be within 10% of each other. Anything much below 300 is probably getting pretty well worn. For example my 617 turbo engine lost compression in one cylinder (100 psi) and the other "good" cylinders were down to about 250 psi; telling me that it was pretty much worn out (438K miles). This engine would still start with no problem down to about 10-15F (before it lost one cylinder), below that you had to plug it in or really work at getting it started.