A nicebig parcel of parts arrived this week from Colin via the consortium so this has allowed me to check the piston liner height, which has highlighted just how spotless the seating area of the liner and the block need to be. With no gasket the liners were still sitting proud of the block, by quite a bit more than they should sit once a gasket is in place!
With more careful cleaning and in particular to the areas at the outer edges of the lands the liners all now go in with a reasuring change of tone when very lightly tapped with a rubber mallet, signifying that they have seated fully. That they then sat perfectly flush with the blockface, not a chink of light showing with a straight edge across the liner top.
Of course they need to sit higher than the block face so when the head is tightenned down it gives a great clamping seal, but only by 0.05mm or 2 thousandths of an inch in old money, which is precicesly the thickness of the gasket.
Should soon be able to start building the engine up, just a few things to button up still.