Everything under the head is basically flush, so the only spacing between the piston tops and the valves will be the head gasket thickness. If I recall the head gasket thickness from Nissan comes in 3 thicknesses. I may be wrong on this but I think they are 1.15 - 1.25 and 1.5
The protrusion is a concern.... here's a few quotes from my original post...
a) Fitting the sleeves are simple and engeneering has to do that.The sleeves HAS TO PROTRUED THE BLOCK.According to specs 0.02-0.09mm
b) The head need to be skimmed after that,because the precoms will stand proud.The specs say precom protrusion are -0.05mm.Dont try to get that,some engeneering guys get it wrong and can mess up your head and head.
I don't think the pistons should protrude more than the sleeves !!!
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