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Classic/Antique Car Repair/M-B OM617 engine performance


I own a 1984 Mercedes 300SD turbodiesel. Has anybody had success making significant power gains with the OM617 5-cylinder engine? The forums I read (and they might be part of the problem) display lots of blood, sweat, and tears for a 15% net gain. Call me naive or stubborn, but I believe everyone who tries isn't using the most intelligent and meticulous approach.

We have three 300D series cars. They have well over 200,000 each.  82, 83, and an 84. I have needless to tinkered a fair amount with them. Each time I have reverted to the way it came from the factory. The most critical thing that I have found is the valve adjustment . It requires special tools and I would suggest a trained Mercedes mechanic.these engines were designed to meet us emmision, give excellent fuel economy and run forever pulling a heavy car down the road at 80 plus miles per hour while delivering 25 to 30 miles per gallon. Two of our care are in show room condition and one is in good used car condition.

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Brad Sears


All automotive including antique and collectible. However if the car has been modified I can only answer in general terms and maybe get you pointed in the right direction.


Automotive tech instructor. Syndicated auto columnist 1970's though the early 1990's. Syndicated auto radio talk show, Ask Brad About cars, CBS Radio 70's through 90's TV Show "Last Chance Garage" 1980's PBS-TV syndicated. Auto instructor for the following companies: Fram Autolyte Holly Carter AMF Ford Motor University Of Conn Blue Hills Technical School Sugar River Technical Center Grew up in a family garage in Needham Mass and turned wrenches from the age of 14.

Manchester Union Leader, Nashua Telegraph, Motor Service Magazine, Yankee Magazine, Popular Mechanics (Saturday Mechanic early 80's), Los Angeles Times, New York Times, and lots more.

More than I care to remember. Basically Franklin Technical Institute in Boston, Northeastern University, Fitchburg State Teachers College, Tufts University, and a lot of factory schools along the way.

Awards and Honors
Moto Award winner. And much more.

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