Cleaning the top was done with a fine oil stone, the top of the block soaked repeatedly in
WD40. This does not cut the metal. I was cautioned against using a Scotch-
Brite pad on a drill to do so. That this machinist has seen numerous blocks and heads absolutely ruined in this way.
Measurement of the block face was done using a machined piece of square stock and a .0001 and .0002 of an inch feeler gauge. At no point was there more than .0001 of a gap on the face. Maximum tolerance was .0002 and no more. This was GREAT news. The block was not damaged or warped.
The next critical measurement was the bore.
Pistons are made to be .00015 to .0002 smaller at the top than at the bottom (measured across the bottom of the full skirt). This being the hottest sustained area in th bore, the top expands, making the piston sides fully parallel with the bore in an engine at 160 - 180 F degrees. The biggest problem of running a cold engine is of a not fully expanded piston top which is then able to torque on its stroke and will make the bore elongated. When the bores were measured they were found to be .0001 out of round. If they are too elongated then the
cylinders cannot be bored out and the newly-rounded cylinders refitted with
over-sized pistons...a few thousands larger than original.
The other GREAT news is that the bores were well within tolerances to qualify to be newly bored!
IN OTHER WORDS THE BLOCK IS IN ALL LIKELIHOOD 99% OKAY!!! This is terrific news.
The bottom end of the cylinders need to be checked out. But the bottom ends of most German and Japanese diesels rarely go bad. Main bearings, etc. will need to be replaced.
This is a good, good start...