Hi Everyone,
I thought I'd share this topic with the group as I know there are a few MB's in this situation.
I have been working on a 250se. A total restoration for a client. The car sat for over 20 years near a beach house in California.
The engine had low compression, about 60 psi or so in each cylinder. I sprayed a bit of oil into the plug holes and did another compression test. It came up to 110 psi. (Oh by the way. I had to redo the head because of a few loose valve guides.) The car has low mileage so I didn't think the rings were shot.
The next thing that comes to mind in a engine that has been sitting for so many years would be stuck rings. I went ahead and used this concoction that I found from the net that made sense. It's part transmission oil, part carburetor cleaner, and part diesel fuel. I squirted a good amount into each cylinder and let it sit for about ten days moving a little a few time so the liquid would do its thing. After ten days or so, I sprayed a bit more before I did another compression test. It was nearly 200 psi.
After a bit of work was able to start the engine & run it for about half hour letting all the oil out of the tail pipes. Then I did another compression test and there it was at 130 or 140 psi where it should be.
The rings have sprung out. The engine runs very smooth and is ready for another 40 years of use.
Hope someone can use this!
Like to Thank Jo, Erick a other members for their help.
Cheers,
Shaun