Technical Engine forensics/ catastrophic failure

The right term is reversion. If you want to see eye opening info, go to John K***e's website and watch some of the videos. It's amazing how much is p***ed from cylinder to cylinder. What you have is very common with any rpm. If an engine is idling, usually the damage is localized.

 

Without more head damage it would make you think that It was not foreign material damage. Would make a good add for forged pistons. I just pulled the intake off a LS and the head of a valve out.

 

Consider #3 piston blew apart and backed thru the intake valve ****tering thru the other cylinders.
Pushrod for #3 intake was broken. But it could have happened after a few revs of that valve opening and closing letting debris back up thru.
May not have been simultaneous. Piston broke/ pushrod broke. Coulda been piston broke, valve kept opening until debris caused the pushrod to break after multiple engine revolutions.

Have you had a chance to tear it down and see what's salvageable? Might have a cranks. 7 rods and pistons, heads to work with. Depends how much debris got in the journals.

 

May have been mentioned already but pushrod probably broke later after debris hung valve, created slack in valvetrain and pushrod hit off center on rocker. Pressurized hot water could have helped move debris as well, especially if piston didn't disintegrate right away.

 

I've had it in the top of a tunnel ram before, that 12 inches of uphill travel !

 

Open carb spacer or nitrous plate that would allow cross over from what a 180 design wouldn't allow?

 

Unfortunately I've seen this twice. Once was a SBC, damage was pretty much identical to what you have and for the reasons given. Once the cylinder seal is broken and crankcase pressure becomes unbalanced, the shrapnel travels in the intake tract to all other cylinders that share that tract, helped along by the coolant that's also now mixed in. It's hard to tell in the pics, but do I see a 'lip' at the top of the hole in the cylinder? Could the cylinder have been the initial failure, with the piston failing when it hit that lip?.

The second case was more extreme. It was a FE Ford that dropped a valve from a broken valve spring, and was being driven by the owner's GF at the time. She was on her way to pick him up at work, heard the racket but drove several more miles to his work. I can only ***ume that it took a very large throttle opening to keep it running because 'stuff' got into all cylinders; there was shrapnel in the air cleaner housing. But the damage in the 'shared' cylinders was worse that what you have, all four of those were beat to hell. Found the head of the dropped intake, couldn't find even one recognizable piece of the OEM piston. There was much less of the cylinder wall left than what you have.

 

Looks typical of damage to other cylinders and pistons I’ve seen before ,,,,,it can bounce a lot of **** around very quickly.

What amazes me is the amount of junk in the lifter valley !
It looks like someone was panning for gold,,,,and dumped their rocks and gravel in there .
It must have ran for some time like that,,,,that’s a lot of **** deposited in there .

Tommy