Broken Hemi.

[coronet68mx]

Hello everybody, I saw this video last night at Nick's garage and i thought it's real interesting, a valve seat broke inside the combustion chamber (the exhaust one)and literally explode, shattered six out of eight pistons also chew up the two heads, help me understand why an exhaust valve flew over the intake manifold through the carb and end it up In almost all the combustion chambers.

 

[mmissile]

My friend in the late 70's, had a valve face do about the same thing. It was a professionally built hemi, with about 8 passes on it. He was sick for months...

 

[RemCharger]

It happens with all motors, just the way the vacuum pulses pull the garbage around

 

[AR67GTX]

Damn, that’s crazy. I would never have guessed that was possible. He had some good spark plug tube seats in the heads - they didn’t want to turn loose of those plug tubes.

 

[Budnicks]

Yeah those low crossrams or any box manifolds easy for parts to jump
from side to side...
I had a 440 with a STR-14 4bbl dominator top
that did that too, like 6,5000 rpm
it broke off an intake valve & bent another
from the same broken valve I suspected...
Off of or in an earlier version of Stealth heads...

Foreign **** Chinese-ism 'alleged S-S' valve
(**** metal had all kinds of porosity in it),
that they/it came with & they were almost brand new too...

It wiped the bearing/s, scored the crank, (polish took care of that)
1 cylinder lil' scratches where the valve head dropped
& 2 pistons beat to hell & bought some good all new Manley SS Valves
for both heads, they were ported heads too...
More expense, I was lucky my head porter Mark Lowe (RIP) helped me out...
I had to try to match the other head, so we just went
a bit further with the port job, so both would match/flows etc.

I wasn't going to take any more chances...
I luckily caught it soon enough, it didn't ruin the cylinders,
just a hone cleaned it up...
Cam & lifters (Lunati or maybe Crane ?)
pushrods (Smith Bros)
rockers (Harlan Sharps) all seemed fine,
Melling HV oil pump had some stuff go thru it, so I put a new one on it
flushed it all out really good...
A call to Uncle Joe's, his Venolia pistons, he sent me 8 all new pistons,
with a lil' more compression zero deck, lil' bigger valve reliefs like 8cc's
'while I was at it' (IT had 0.120" clearance valve to piston reliefs prior too)
& new Childs & Alberts new rings/bearings & rod bolts,
Magni-fluxed & x-rayed everything to make sure, no damage or cracks
& 1 new *whole head it was pretty bad, I didn't want to repair it
& take that chance...
(they *440source made it good, the 1 head that is, he sent a head gasket too)

A month of BS, PITA was the worst part...
Tri-Valley Machine, Pacheco Ca. Manuel got right on it, did a great job...
Another $1500 in machining, parts & gaskets I had to pay for...
Could have been way worse...
Live & learn....

My race motors with 8 stack fuel injection never had them issues
it can't travel from cylinder to cylinder, unless it goes up & out
& then gets sucked (1 in a million) down another injector stack
out of thin air...
On my tunnel rams either, maybe just got lucky...

 

[threewood]

I learned this after I destroyed my 2.2l T2 4 cylinder. Valve lock failed, dropped valve in #3 chamber and killed it but the other 3 pistons were destroyed as well. It just happens.