So as suspected, the piston is burned thru. We haven't pulled the report from the onboard computer, but suspecting it will support a fuel delivery problem in #1. While we are at it will run the report from the other engine and I am keeping my fingers crossed...I thought these "smart" engines where supposed to protect themselves from problems like this?

http://www.intored.net/images/496/49...ons_003-50.jpg

http://www.intored.net/images/496/49...ons_004-50.jpg

http://www.intored.net/images/496/49...ons_001-50.jpg

http://www.intored.net/images/496/49...ons_005-50.jpg

Naughty kitty , I had the same problem last year. My piston looked exactly like yours... I'am just getting mine back in the water I feel your pain...

What did you attribute the failure to? For giggles, I contacted my insurance agent (statefarm) and was told that contaminated fuel is a specific exception in coverage.

Leaned out cylinder, assuming bad injector. Never tried ins claim. Just for my own knowledge how many hours were on your motors???

200 hours...really hurts

it looks like there is one spot on the edge that is burnt thru, that would make me wonder about detination in that cyl?
looks like there is a lot of black on there for it to be lean? lets see what some other have to say. sorry for the loss, we've all been there.
larry

I think the black is a post trama sign...once the burn got down into the ring lands, oil was free to get into the combustion chamber. What struck me strange was the relative area of clean on the head. It almost looks like a coolant leak.

What you are seeing on that piston is the result of a piece of the top of the piston by the valve relief that sometimes breaks off on the 496's with detonation or a lean burn condtion. t
This piece will bang around in the cylinder and make the marks you see on the top of the piston and cylinder head quench surface. Obvoiusly from the overall damage to the piston side and ring pack the motor was run quite awhile after this event occured.
If your interested in a new short blcok with forged pistons,HD rods and such, give us a call and we can get you pricing and delivery on an a short block and such.

Best Regards,
Ray @ Raylar

Thanks for the input Ray. If the respected builder (PowerSource) in my area had not been so responsive, my next call was going to be to you. I don't believe it was detonation as the other 7 pistons all look good with no signs of peening on the head. so this points to the injector, which we will look closer at this week.

To prevent this problem from re-occuring in this or the other motor, can someone recommend a decent fuel additive to clean injectors?

I was out at the builder on Saturday. The block was sitting in the honing tank and looked like the .030" oversize bore cleaned up the damage. I also noticed the new pistons have a symetrical head, with valve relief on both sides of the wrist pin. Is this a newer design, or just unique to this manufacturer?

http://www.intored.net/images/496/496_Pistons2-50.jpg

http://www.intored.net/images/496/496_Pistons1-50.jpg

http://www.intored.net/images/496/496_Pistons3-50.jpg

ny codes or tell tale signs of this happening?

Rough running or ???
Good luck and keep us posted.
I tohught the earlier HO's had better internals. like the 2002 and 2003 496 HO's? (forged)

Dennis