Just pulled the head. Is this bad?

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The_GDFP

Master Spanner Spinner
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I tore this down last night. Said it just stopped running. I'm sure it did. lol

Not s'posed to be twisted.
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Wasn't an S-cut when it went in.
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Rod that can poke around corners?
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Guys wins a bunch of 40+ races over two seasons, no problems. His kid runs it one lap in 12" Expert (leading), pushes it back to the pits. Prolly didn't heed the "short-shift it" advice?

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Why so destroyed?
Too many revs. Motor was built to sign off at 9K. It went higher this time.
Best I can tell, the heavy piston snapped the wrist pin, and sunshine went sour. Piece of sleeve got wedged in 1st gear, trashing the input shaft. Valves bent from loose piston debris. Hopefully it didn't jar the seats or guides bad enough to loosen them or the head's toast too. Ah, well. Chamber and dome say it was time for rings, any way. lol


Wat kit was he running in that
V2 with small cam, TB stroker, Akunar 65.5 piston. I have a couple of those slugs that have run for 2-3 years. Just have to keep them in their design envelope. I love the smooth dome for flame travel. I've switched most of my big builds to 14 or 15mm pins, for this sort of reason. And/or much lighter forged pistons.
 
just remove the fragments. put a new set of rings in and i would suggest an oil change but you dont really need to. should be all good to go again. good luck and happy riding.
 
ouch! you wasnt kidding when you said it tore it up. shouldnt of looked at this i have been wondering if the lil 13 will be ok for the rpms i wanna sling my mutant motor
 
seeing that it hasnt dropped a valve, you would think the piston has failed & cracked around the pin letting it rip out causing the mess you see
 
over rev, stretched conrod, kiss kiss.. pictures show the damage lol..

happens all to often for people that just rape engines and not ride them to there build design..
 
over rev, stretched conrod, kiss kiss.. pictures show the damage lol..

happens all to often for people that just rape engines and not ride them to there build design..

Are you telling me the build design of engines is not to be raped? haha
 
just remove the fragments. put a new set of rings in and i would suggest an oil change but you dont really need to. should be all good to go again. good luck and happy riding.

I checked with my dad, and he says it WON'T buff out :(


ouch! you wasnt kidding when you said it tore it up. shouldnt of looked at this i have been wondering if the lil 13 will be ok for the rpms i wanna sling my mutant motor

That Wiseco I sent you has a better 13mm pin, and a bunch less weight. Besides, your piston is a block and a half away from the head:mmph:


seeing that it hasnt dropped a valve, you would think the piston has failed & cracked around the pin letting it rip out causing the mess you see

Yup, either the piston or pin failed first. I'm guessing pin, but I wasn't in there went it went to Hell. Pretty happy aboot that. TB valves almost never break.

over rev, stretched conrod, kiss kiss.. pictures show the damage lol.. happens all to often for people that just rape engines and not ride them to there build design..

Yup. Needed rings, from the oil on the dome, but look at the nice clean edges. Quench area was doing it's job, keeping rings cool. Bore looked OK, besides where it was missing. Intake valve sealing face was concave and the cam shows chatter. Valves were being floated, sure signs. I love an autopsy:)


Another piston fail that was unable to break a TB valve. Suckers are pliable:)
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And another... This one ticked me off. 5 minutes or less, and the supplied piston failed. I'd said it would, but hoped not as soon. Bummer is, it loosened the guide in the head, so it was a tougher fix.
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Yer ive been doing it all wrong .

Nah, guys like you help guys like me pay their mortgage. Keep up the good work, mate:thumbup:

Kidding aside, Damo, if the intake lash starts tightening up on that SE head, STOP.
The 4mm stems WILL snap and pop the head off the intake valve.
 
The shop I ran, 15 years ago, did the repairs for a Top Fuel drag team. We'd get a pile of heads, 10-15, once a month. Best I saw was an exhaust valve head pushed most of the way out the sparkplug hole. Billet head are easy to fix, though. Weld, machine, ship, wait for it to come back with a different issue:)
 
Are you telling me the build design of engines is not to be raped? haha

im not saying dont rape them lol, but im saying people rev the hell out of them beyond there capabilities then have a cry when it fails.
a stock engine these days will out live a TB equipped engine as the valves will float well before destruction time..

see the Chinese aren't all that silly lol
 

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