I just checked this company’s website. Since you can read German, db4690, it’s:
I see it’s not located in Bavaria but south of Stuttgart. The auto repair shop owner who gave me their phone number mistakenly talked about Bavaria as their location.
Their website makes a reputable impression to me.
How they can give me a quotation which is so different from the Mercedes dealer’s quotation, still puzzles me. But maybe this is a very useful address for owners of older Benzes.
@H.D.
I took a look at that website, and these guy seem quite knowledgeable
I want to give you guys some news about my worn camshaft:
I bought the new valve drive parts I talked about in my last posting (camshaft, rocker arms, sprocket, adapter for distributor arm, hydraulic lifters, timing chain - see first picture). Everything looks like good quality.
I installed all these parts on Monday, plus other parts which are not in the picture (new valve stem seals and the rubber seal of the upper front cover including camshaft seal).
All went well, except the loosening of the srew which holds the distributor arm adapter at the front face of the camshaft. The Allen key turned round in it’s head. I had to drill the srew head off.
The complete job took me almost eight hours.
In the second picture you can see the wear of the first cylinder’s intake cam of the old camshaft and the corresponding rocker arm. The wear on both parts adds up to 0.09 inch, which reduced the cam lift, thus the valve stroke by almost 30 % (0.32 inch instead of 0.45 inch). The wear on the intake cams of cylinders 2, 3 and 4 is a little less (hardly any wear at the intake cams of cylinders 5 and 6, and only very little wear on all outlet cams).
Anyway – this wear was the main reason for this thread and it’s title “Mercedes 300CE rough idle”.
IDLE ISN’T SHAKY ANYMORE !
The smooth straight six engine feeling, I was missing so much stopping at traffic lights, is back! The engine feels like new!
However one of the new lifters seems to be a little noisy, particularly when the engine is warm.
All lifters aren’t far from being completely compressed now. I measured them this morning when the engine was cold with the rockers on the base radius of the cams. According to my measurements the intake valve lifter of cylinder 6 has the smallest rest stroke (0.1 mm when the engine is cold). And according to a stethoscope test I did today the ticking sound seems to be coming from cylinder 6. So I guess there is a metal on metal knock taking place in that intake valve lifter.
I’m considering to install thinner support plates on top of the lifters (1.5 mm instead of 1.8 mm).
As for the other old parts:
I measured the new timing chain (36 inch, pitch 3/8”) before I installed it and the old one with the same measuring tape. With the naked eye you can hardly see any stretch - maximum a quarter of a milimeter (0.01 inch) !
It also bends as much sideways as the new chain, and there doesn’t seem to be any wear on the old sprocket!
I tested the old hydraulic lifters again after disassembly. I had to push them out of the rockers anyway because I reused the a.m. support plates on top of them. They don’t collapse under pressure at all. I will keep them as spare parts.
The old valve stem seals were quite hard, especially the ones for the outlet valves.
So was the camshaft seal.
The new camshaft rotates very smoothly and without any lash in it’s bearings and the bearing surfaces look perfect.
Now I hope that the oil seapage at the front of the engine is history too. At least after about 120 miles everything is dry so far.
Quite a saga, H.D., and quite an education for all of us.
For future reference, a vacuum gauge should have showed a problem up like this pretty easily and possibly shortened the process a bit.
I agree !
I spent many hours hunting for the scource of the problems with my car, and I learned a lot along the way.
Some people suggested I should stop spending any more time and money on that car and get rid of it. But not only did I want to get it to work well again, I also wanted to understand what was wrong with it. And I think it was worth it.
Plus my wife doesn’t like the idea to get rid of this car – she thinks it’s a beautiful and timeless classic, and I think she’s right. Sometimes when I return to my car on a parking lot I find a name card stuck under the windshield wiper asking me wether I would like to sell it.
“…a vacuum gauge should have showed a problem up like this pretty easily and possibly shortened the process a bit. …”
Okay, you’ve convinced me, I add a good vacuum gauge to my shopping list.