gnolo,

To answer your question simply, I would say "yes" that the intended units called pounds are pounds per square inch. And they are typically pounds per square inch over atmospheric pressure.

I hate to get nasty discussion on compression going, but the reported values are approaching those of a high performance gas car, not a Diesel, and in my neck of the woods I think if I could get the car started it would be by pulling it down the road at thirty miles an hour in third gear for a few miles.

With a compression reading like that I would invest in a wet compression check to see if the leakage is going past the piston rings and cylinder walls, or if it is due to valves and possibly valve timing problems. With that in hand, I might do a leak down test to find out where the leakage was going as well. Then I might invest in a chain, if the test results supported that the chain was going to help. Otherwise you might as well face it, you're a victim of prior owner abuse. If the car is really nice, I might invest in a rebuilt engine from a place like Metric Motors, or rebuild it locally if you have a source of good independent mechanics familiar with these cars. Running the car trailing a cloud of nasty oil smoke just because you can does not sound like much of a choice to me. I like my cars and I would have a hard time liking a machine that was borderline EPA disaster material, and might abruptly decide not to run once I got somewhere and shut it off.

Good luck, Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)