1300mpi Compression test

[buckman63]

Bought a 2001 Cooper S500 a few months ago in quite a poor condition as a restoration project.I,ve got bored of doing the bodywork so this afternoon I did a compression check ( all plugs out, open throttle and rockers not checked ). Can somebody please confirm what readings I should be getting on a 1300mpi ?. My reliable old gunson tester came up with 210 - 204 - 200 - 190. Now that seems a little high to me, but all close readings ??. My downloaded Haynes manual may have hidden the reading somewhere but I can't find it !!!
I have no history with this car but it has a 5 speed box, high - lows and a full sump shield, so I guess it may have been tuned ???

cheers

Bob

[Cooperman]

A figure of 210 lbs/sq. in would be a compression ratio of c.14:1 and 190 would be 12.66:1.

[Mr2Mike]

You simply can't estimate static compression ratio with any reasonable degree of accuracy from a simple compression test. The important point of this test is cylinder to cylinder variation, which seems to be fairly reasonable in this case.