Also, I have some good lq4 pistons if you need them with the rod hanging on them still. If you were wanting to do a quick cheap fix. You can have it all it would cost you is shipping down and shipping me your rod back.

 

As BlackGMC said. It indicates wear. Might just be flash and reflection in the picture.

As MJ points out it could be a send ring land busted that would be hard to see without the pistons out.

You really have a strange condition. I can see broken ring or blown headgasket affecting 1 or 2 cylinders. All 4 down in compression and nothing obvious with the head off is seriously strange IMO.

 

I find it odd that four pistons that operate independently on the same side would loose compression at the same time, Im swaying more towards the problem being with the head

 

Quick update:

Engine removed
2 Broken rings on 1 piston, still pulling others. (piston tops were intact on all)
New 6L getting the cam/springs/sensors etc...
will have pics later, I'm covered in oil right now
Broken pulley puller .....

 

Are you going to swap in another stock 6.0 with your cam and valve springs and cut the boost to about 6 1/2 lbs until you can do a 408?

 

Yes, except for cutting the boost.

 

Glad you figured it out at least. Didn't you run around for a while without an updated tune?

 

You don't suppose that this engine had this problem already do you? Maybe that is why it was pulled out of the truck? Maybe it just got worse with the boost.

 

glad you found the problem, interested to hear the results for the remaining cylinders... but for now concentrate on getting the other motor prepped and installed

 

Sucks man, dont know how you do it. First the 5.3 and now this. Something like this would set me so far back I would be eating beans and rice for a very long time.