Hello again everyone.
I have a 1985 280CE Euro with a bad engine. I brought it to this shop in CT. who advertised an M110 for sale. I saw the engine running in the car, and agreed to let them put it in my car. These guys seemed like car guys so I was pretty comfortable with them. As I left I told them to do a compression test just to make sure the engine was within specs. They told me that it was with each cylinder showing about 130 psi. they installed the engine and when I went to check it out, I noticed the idle was rough. They said something about the timing, I said ok, but fix it. I know from past experiences that this engine, when running right will idle very smooth. They could not get it to idle, so I would not except it. They again checked the compression, and the engine had very low compression in 2 cylinders. They took the engine out and only put new rings in. Reinstalled the engine, and low and behold, it still would not idle correctly. Those same two cylinders had very low compression. There explaination was that the cylinders must have gotten gas washed when they were oringinally starting it and ruined those cylinders???
Now they have another engine that has been sitting for a few years. I told them lets do a cold compression test. We did and we got readings of between 20psi and 150 psi. I told them to squirt oil in the cylinders and see what happens. Nothing changed so, I assummed the rings are bad. The said the rings must be frozen, and they poured oil into each cylinder,and said they wanted it soak for a couple of days. When we redid the compression test the compression was between 145psi(low) to 195(high). They think this is a good engine, I think not because 50 psi difference between high and low is unacceptable. I also think that these readings came up because who knows how much oil they poured into the cylinders. I will not accept the car, or pay them until it is running right. I hope some of you can give me some feed back on what you think.
Thanks so much, any info would be greatly appreciated. If you would like to e-mail me: jn67mb@aol.com

Thanks again
Jack Newman

I'm no "uber" mechanic, but I did not fall off the turnip truck yesterday.....a 50 PSI spread between the cylinders is not a good thing. How is the head?...maybe its a valve spring, or related issue.

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1993 190E 2.6 135k
1989 Ford Thunderbird SC 5 Spd 79K

Has anyone done a leak down test on this engine?? That would Really be the most telling... @ least that would have been my first step after a poor compression test.

Jonathan

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Blue Ridge Mercedes
Jonathan Hodgman
http://www.blueridgemb.com/
Enthusiast Service, Restoration & Tuning.
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Located in the Atlanta area
Specializing in all pre and post merger AMG's including Hammers and DOHC M117 engines.
Mercedes Repair Atlanta

I had idle problems on my 1985 280GE. I took it to a reputable mechanic who could never diagnose and fix my problem. I went to another mechanic who fixed it perfectly. Problem was 3 injectors and valve lash adjustment. These m110 motors will run real crappy when valves not adjusted correctly.
I also had an issue with cold idle staying too high and not idling down when warm. This turned out to be a vacuum leak in the plethora of "air-slide" tubes under the intake manifold.
One final note. My compession had variances of 15-20 and I am no mechanic, but I think valve lash may affect these readings. So here are some things to consider and keep in mind that all "good" mechanics are not created equal.
Mike

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1981 300SD (171,000 miles)
1985 280GE (205,000 miles)
1995 Dodge Cummins Turbodiesel (278,000 miles)

I recently had idle problem with my m110 motor and the problem was the intake manifold gasket was leaking. Check for leaks in that area.