You may want to verify the accuracy of your HF gauge. Mercedes spec for a new engine is 22-24 bar (319- 348 psi), wear limit is 15 bar (217 psi)
If it is accurate, your combustion/pre-combusion chamber may be packed with carbon, raising the compression ratio.
Quote:
Originally Posted by mikeyfev1
Because of this forum I decided to do a compression test on my recently acquired 1985 300D KaliKar before getting serious with money and time. The results are:
#1 450 lbs
#2 ???
#3 400 lbs
#4 450 lbs
#5 450 lbs
The bad part is that I couldn't do cylinder #2 
I was doing the "glow plug" method. Managed to rip the screw-tip off plug #1--the little nut was so tight and corroded on. BTW, has anyone noticed that little glow plug wire nut is SAE 5/16"? Not quite 7mm or 8mm.  As soon as I pulled out a nice new 5/16" wrench those nuts came off easily.
Anyway, I was using my new diesel compression tester from Harbor Freight. Gauge goes to 1000 lbs. Could not connect to cylinder #2 because I couldn't fit all the adapters between the head and a protruding box on the block-side of the IP. You install a glow plug fitting, which sticks out about as far as a glow plug, then a right angle fitting, which wouldn't fit on #2, and then click-on the gauge fitting.
So I'm going to presume for now that #2 is OK. The engine was starting quickly in the cold (well, in Houston cold  ) but had a lot of off-throttle clattering (meaning like when coasting down to a stop from freeway speeds). The driver-side engine mount is squashed like play dough in a press, the right-side engine shock is missing and I want to install new injectors. I have performed 2 valve adjustments (second one a few hundred miles after the first to confirm). After all of that I hope the clattering goes away. What are the symptoms of a spun rod bearing? |