JL Sargent

With 100K miles on the truck and an engine ticking noise for 500 miles or so, I thought maybe one of the AFM lifters on this truck had dropped. I began to tear into it. After pulling the lifter trays I found a nickle sized piece of a piston skirt wedged under the tray. Knowing I had to dig deeper I pulled the oil pan and found the #2 skirt with a nice chunk broken out. After seeing that I went ahead and pulled all the pistons. As expected compression rings looked pretty good but several oil rings were pretty locked up with carbon.

I plan to do an AFM delete, 212 218 Comp Cam, Valve seals, LS6 springs, new oil pump, timing sprockets and chain with LS1 damper, pistons, rod bearings and headers.

I'm just wondering if any of you have been here before?

JL Sargent

I should have mentioned that the motor internally is very clean with no sludge at all. All bearing surfaces look very good. No other problem found except for the piston on the photo. All cylinders checked with a bore gauge and well within GM specs for a 5.3. I found a max of 3 tenths taper and that wasn't even the #2 hole. All original cross hatching clearly visible.

FFDP

iTrader: (2)

Well, you don't see that everyday.

One of them weird things you know, maybe a defect in the piston to begin with but took a long long time to finally break.

JL Sargent

My dad cuts hair and one of his customers is the GMC dealership manager in a nearby town. He told us that the 2007 has oil consumption issues and a broken piston skirt can be the result of this. Now I can report that keeping oil in it is a constant battle but I have never seen the oil light come on but often it is a quart low. So who knows?

JL Sargent

About to put this all back together. Just cleaning everything right now.

Yipykaieh

My aluminum 5.3 was built on the factory assembly line with one extra windage tray nut that was loose and free roaming in the oil pan. This loose nut collided with number 8 piston and broke the skirt, shattering it. My photo of the failure looks nearly identical to yours. There is no physical space for the nut to migrate down from the valve covers had this nut been introduced post assembly process. The nut was a ticking time bomb since day one. I too has VLOM issues however this did not take my 2009 GMC Sierra out of service, the broken piston did. My last GM truck ever. Upon disassembly,I can see why all the class action lawsuit are piling up.Poor engine design and material selection among many concerns here. I am building the engine the way I feel it should have been manufactured in the first place.
polishing a turd on my dime....

swathdiver

Care to expound on your thoughts here? What is a poor design and what poor material choices? What will you do different?

00pooterSS

iTrader: (40)

That's wild. Never seen or heard of that one.