Any of you familiar with the 840 X-XX motor (fx. r1223) -when lifting off alu-top I find some quite accentuated marks in all 4 combustion-chambers-All situated in the squishband area .All pretty the same courseness. Looks like someone has banged on a flat screwdriver and left marks in a random criss-cross pattern.. These "marks" is also to be found at corresponding/same location on each piston-crowns First thought were massive pre-detonation but then I thought..could these corrugations-marks be there for a reason? namely to make the fuel/air move into squishband in a kind of erratic/swirly way? Or have I finally closed the circle to full-blown madness???? Looking at Malcoms pixes showing head and top of pistons I can't see these marks at all,maybe they're not on aftermarked pistons,and might have been removed in head when it was rectified ??? Also I noticed the arrows on all 4 pistons-crowns on mine has the arrow (that I've always believed should point 2wards flywheel) is pointing 2wards the timing-chain. Untill I noticed the squish-area on pistons corresponds with same area in head.... So Must be right -right? I'm near the end of mission of bying in new parts one or two smaller items left then its all personell to the pumps here....Even found the 1,9mm head-gasket (gr.2) as the compression is already high enough.. PS: I just saw an ad on LBC right now showing the same "pattern" inside head,which made me feel a little better (the 4 Kronenbourg Had nothing 2 do with it) then again-other ads does not have them ?? What says the tech-brigade ??? -As always;Any/All well informed info/tips greatly appreciated! Thanx in advance.. -Reid.