Ah.......didn't realize that.
I wonder if the V10's do have spring failures then?
If not....gotta' be detonation and poor fuel quality/injector causing lean burn conditions.
Al

 

I think it's a combination of his engine work lowering compression further than the OEM 8.4:1 and the crappy fuel octane rating he's using.... I think he needs to get a completely custom tune, on a dyno... personally I'd tune that truck to 91 Octane.

 

I dont think valve spring is the issue here.

Notice those thousands of little marks in the surface.... THAT is from detonation caused by 87octane.
The ringlands and edges are notorious for breaking off after significant detonation weakens them. I would guess the outer edge chunk broke off and punctured the top of the piston as it probably got caught between the valve and piston top.

 

Valve spring not an issue on the V10. It probably dropped a valve seat.


Yes, 87 way to low for the bored over engine. I'd be running 93 octane...

 

That was my first thought also, but you do not see any seat scoring at all on the surface anywhere around the hole which you would be expecting to see.


Mike

 

I guess if it were mine, I would run tecron through or Seafoam to clean injectors/fuel system.
Did you move injectors and throttle body from old to new block? I know the injectors rarely fail.


Mike

 

Thanks y'all! Sorry I've been away.

I know that it's bored over, but I also had the block and heads decked slightly to help. Although I'm dying to get a programmer.

I re-used the same injectors and throttle body, but the injectors got juggled into new homes.

The valve seats were intact and the heads were reusable.

 

This piston looks just like the one from my boat motor. (chev 350 with carb.) the long block was rebuilt and same thing happened again. cyl #6 both times.all other pistons were fine. second time was at 8 hrs run time.traced it to ign. system

 

Can you sense detonation? Does it feel like a knock or something? Can I tell before damage is done, or is it a silent killer?

 

I run 89 in my 04 Hemi now. Didn't for the first few months of ownership. Maybe its just me but the Hemi responds so much better to the 89 octane vs 87. Sometime i'll see how it does on 91.