holy shit ur right...that looks loose man....with the piston at TDC, can u move it a lil bit with ur hand??? hold the piston with ur fingers and try and see if it moves or not...coz my supertech doesnt move when i do that...
got a friend who told me that his JE pistons in his old B20B moves around when he does that... makan engine oil kow kow... he said he has to top up engine oil every full tank... gila man
also u playing turbo right? why ur pistons look like high comp 10.5 pistons? why not get the mangkuk one?
yep, that is loose but without you putting the pistons at TDC, hard to say how much p2w clearance you have, but it still looks very loose IMO. No way you are going to run those pistons, A lot of noise when engine running for sure not to mention compression and oil seal will be out. As for actual oil and compression sealing, that depends on oil control rings and hone, and also how much compression ring gap with that kind of looseness. But with that kind of looseness. No, it's not going to work. If you can return it, get 82mm, but by the looks of it, you sure you were running 81mm pistons before this? It seems VERY LOOSE. even my b16a with worn liners aren't that loose with 81mm pistons.
Looks like you might have to get a new block, but if you do, make sure you have a dummy head (actually just a piece of metal with holes for the boring tool to torque to the block so that bore deflection when head is torqued is kept at a minimum. Also block guards are supposed to be installed before you bore, not after, if you've never done it that way. When you torque the head, usually the bore will be slightly out of round, minimized with block guard, but not totally eliminated. That's why now even the machine shop I sent my block too has a dummy head to bore, and the blocks they bored can actually hit 9500K safely, and not seize up even when water temps sometimes hit 110C.
And madman, with B16a block and 77mm stock stroke, that is not high comp. It is high comp only, if it has a 89mm (or more) stroker and/or bigger than 84 mm bore.
PeterJ, those are new version wisecos, marking now placed at piston skirts. Dunno about you, but my wisecos from 2 years ago also started having the logo at skirts already, so it's not really new versions already. :P