I was wondering what the engine difference between the 300D and the 300SD of oh lets pick a year say 1983 or earlier would be. It's my understanding that there both 5 cyl. and of the 617: series. I'm just curious!

Assuming that you are talking about 300D-turbo's, I think both engines are the same (5 cyl, 617...). Before '82, US model 300D's were normally aspirated and 300SD's had turbo's.

Yea I was talking turbo. It sure seems that the SD would at least be dialed up with a few more ponies. Given it's larger size and weight. I know my 83 300d Turbo is slow off the line I can only imagine what a big SD would be like. I would assume that at highway speeds it would do ok.

I have often wondered the same thing. My W116 SD is engine no. 617.950, W123 300D Turbo is 617.952, W126 300SD is 617.951. They all have a different end no., but the same engine manual of 617.95. I think each has slight differences like the later W126 300SD has the cyclonic oil separator in the air filter which the W116 does not have. My '79 300 SD is incredibly fast. The kickdown switch at the base of the fuel pedal is a lot of fun. I hear they are slow, "Super Turtle", but not mine. Maybe it is because it has a new turbo? I also don't have any problem with hills, or lagging off of the line.

hey Patsy why did you replace the turbo? Did it freeze up or what? My 83 300D turbo runs ok but I sometime think it should be 1) quicker off the line and 2) have more power at higher speeds. This is my first MB and I don't have any thing to compare to. I've always thought that it should run better. It uses absolutely no oil. Starts well except when it gets into the twenties like it has lately.Even then it only tanks a couple of tries. Also while I'm taking up space the previous owner told me when the car only had about 20K or so the dealer replaced the short block. She said they never she had no idea why, she thought they said it was a recall? If any body has any insight on this let me know. Again just curious.

My turbo was leaking oil and burning it in a major way. I have never heard of a turbo going bad(although I'm sure they do) except for the oil leak. I wonder if timing or injectors might have something to do with sluggish behavior. Hopefully someone will know. You might try bleeding the air from your fuel system like the manual says. When I replaced my leaky hand pump, mine started right, up unlike before, in colder weather. I think I run much better now too. Do you have the kick down switch when you floor the accelerator pedal? Check it out, it really is great for passing, or when extra power is needed.

I just read a post about the aneroid adjustment being responsible for sluggish behavior. Do a search under "aneroid".

[Edited by patsy on 12-31-2000 at 11:07 PM]

Slight differences
 

The only differences between the OM617.95_series are so that they will work in that chassis. Like oil filter housings, oil pans, motor mounting, & ect. Every engine can have a slight variation in power due to tolerances durning assembly. Used to dyno all diesels at another dealer & found up to 5-6 REAR wheel hp differences on these engines.
A lot of 1982-83 engines USED too much oil, factory honing process was incorrect & rings never seated.

My '80 300SD accelerates faster than my father's '85 W123(turbo). The accelerator on my father's car takes a firm push to get it going. Mine on the other hand is almost like driving a gasoline car. When the turbo spins up, you really feel the power rush. At highway speeds (60-70), acceleration is really good. I figure that is attributed to the turbo being at full boost at that speed (3000-3200 rpm). I get the same thing from my VW Passat 1.8 Turbo. Granted the VW moves along faster, but like my Benz, it accelerates faster going from 65-75 than it does say, 55-65.

The 1985 cars use a different torque converter & the rear ratio is 2.88/1 instead of 3.07/1. IF the 85 model is a California version the hp is also less.

I found most of the info. I needed in my CD manual. I also got a really good feel on how the turbo and related control's work! I am going to check the boost pressure next week when I can get my hand's on the proper gauges from the shop. I will keep you posted with the result's.

TX Bill the plastic line that connect's to the aneroid compensator goes through an electric valve then on to the intake manifold. I plan to take a look at that hose this week when I get back to the shop where I have all my tools and equipment. One thing I'm not real clear on is the function of that electric valve. Is it normally open or closed, and what effects would a malfunctioning valve have? I don't mean to sound as though my car is a "dog", but it does not sound as though it's as fast as some other's I have read about.

Yes it located kind of behind the power brake booster on the firewall. The line from the manifold goes into the bottom, the line from the aneroid goes into the top. The 2 wire connector connect's from the bottom. My cd manual calls it a change over valve.

The oil consumption wasn't a ring problem but was a honing problem, as the angle that the cross-hatch was finished at was 20deg from the correct angle. Many engines used way too much oil until 100k miles or more.

So MB just replaced the short block's on these engines? Sound's real exspensive!!!