Compression for the 8:1 Engine

Per Stenius asked:

Here is a quick question regarding the Series 1 6cyl engine: I have an engine marked with 'S' which the owner's manual claims stands for standard, which I presume was 8:1 compression ratio. The owner's manual says the markings used were /8 and /9 or, later, S and H (standard, high). The factory manual says the markings used were L and S, however. Nigel Thorley's book seems to mention all three, ie. L, S, and H. Does anyone know what these three designations mean, and specifically, was the S indeed 8:1? Also, some years ago, before the PO did a valve job on the engine, a compression test was done with the results 135 115 135 145 140 145 What should this result be for a 'new' engine with the S marking? I suppose doing a valve job also changes these readings quite a bit? The engine runs nicely as it is, I just got curious about this... Thanks.

These compression pressures are for the 'S' (standard) 8 to 1 compression engine. Yes, 'S' DOES mean 8:1.

Expect an even 145 psi when the engine is in very good condition (low miles). Should hold at least 125 psi for some years.