Something's gone terribly wrong... (hole in piston)
So, I recently finished reassembling my engine. After some cranking (to be expected), it finally started. It seemed to run alright, but was making a significant rattling/ticking noise. The ticking was very consistent -- sped up and slowed down along with revs. I wasn't sure what to make of it. I know it wasn't the cam chain because I just replaced the tensioner. Anyway, after a few minutes of running, I heard a louder crack and it died. Pics below show what I found when I investigated. Note that the damage is only to cylinder 2, all of the others are completely fine.
What happened? Did I replace the cams incorrectly and cause a timing issue? Was there debris inside the cylinder? The hole in the piston doesn't appear to be burnt or melted...just punched through. Same goes for the spark plug. I'm just not sure what I did wrong.
You messed up the timing, the piston hit the valve. Then in bent. Then it broke. Then it banged around in there and punched a hole.
That motor is junk now. Sorry!
ALWAYS check and double check your timing. Then spin the motor through by hand several times. If you don't feel any clearance issues then check the timing again and finish putting it together.
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i'd suspect a rod failure, or if valve springs were removed, a keeper may have popped out....there should be impact marks from other valves touching the pistons, either intake or exhaust if it was drastically miss timed...
it's a 98-99 so parts should be plentiful and cheap
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"SuperCharged fun with 751."- Book of Kawi 7:51
Anytime you disassemble an engine, always mark where the timing was prior to you fiddling around with it, not to mention following step by step in the manual.
Shit happens, sucks, but hopefully you learned from this.