if you saw detail of the piston its was melt cause by detonation,If valve touching its won't be on a side and you can saw a very new hit mark by valve , if head touching you can saw their the mark was around the piston if i can get back the picture piston touching the head i will post it hereloo, that doesn't seem typical of a detonated piston. Detonated piston have telltale signs of melting at the edges, and pitted surfaces. Which aren't apparent in your example.
It looks more like a head piston contact, or piston valve contact, and not at high rpms. coz at high rpms, all you get is a 3-20 pieces of piston in the windage tray, if the tray hasn't broken yet.
I also seen another forged piston (CP) with that kind of breakage. the piston actually hits the head at high rpm because the piston head clearance (or quench, as I've seen it referred to in some books)
The hot spots are always near the valve pockets because even on the stock engine, the hot spots are there as well. I think there's a picture I posted a while back of my engine with detonation signs on pistons, and as can be seen, it's localized to the valve pocket area mostly.. then again, most other engine too. I don't think it's cureable, because of the distance between the two exhaust valves, and that thin slice of aluminium seperating them.if you saw detail of the piston its was melt cause by detonation,If valve touching its won't be on a side and you can saw a very new hit mark by valve , if head touching you can saw their the mark was around the piston if i can get back the picture piston touching the head i will post it here
For NA CP piston i not like much i have tested to install on 2 engine and its generate 2 much heat at valve pocket(hot spot) but for turbo i could tell you YES its really a nice piston i ever saw for turbo after MAHLE & Fierra
no matter what stand alone ECU/Piggyback you tuning your car running in 13.5:1 < CR with pump gas (petronas,sheel,mobil,bla bla bla) daily driving confirm your piston will melt/blow your engine
some sample picture show below using wesico 12.5:1 CR and skim head&block and around 13.5++:1 CR after 15000 KM tune with microtech LT 10s
yeah dulu la for jun3 cams.... now skunk2 cam..bro..
thought ure using Jun3 in b20b..
did u do some mod on p3f for valve clearance(i mean valve pocket) to support high lift frm tht cam?
Do NOT VTEC 8,200 rpm all the way KL to Ipoh..............hi there
sorry i'm new in here
i'm not quite understand some info in here
so i want to ask some question
actually i'm interested to get honda with oredi change the block to b20b and b16a head
what i want to ask is the reliability compared to the standard one, like b16a, b18c
not rojakla, like i mention just now
is there any restriction that to be observe when using this setup