Thank you for that introduction, TDIMeister.
I'm more interested in what your pistons look like right now. I am going to guess you have some 'upgrade' nozzles, perhaps a tune that has the engine way up in horsepower or maybe you simply drive very 'spiritedly'.
The first pic you have seems to 1) not have the valves turning, as the same spot is blistered on the valve seat and the valve. Probably if the valve were turning as it should, the valve would be spreading the heat over the perimeter of the valve. 2) that picture shows the bad erosion that the aluminum that should be between the injector bore and the intake seat is GONE. The valve is ruined. I'm guessing the lifters are dished and not rotating. I bet the cam is shot.
The second picture, again, shows severe overheating of the area around the injector bore. At the very edge of the picture, there is another chunk of valve missing into the seat. This is a variation of the first picture, not quite as bad, but no less, a ruined valve and the seat would need rebuilt.
The third picture is most telling as I can see it is the #1 cylinder. There are several interesting points on the head. 1) The nozzle is burnt and appears to be pitted. This is a very hot injector, probably overfueling is the worst on this cylinder. The overheated injector usually causes the nozzle to fail and it has a runaway fueling 2)There are extreme pits on the manifold side of the cylinder head at the edge of the gasket. The pitting is extreme. 3) The front side of the head appears to have been very hot and lost the headgasket seal. 4) The top of the intake valve and an area under the exhaust valve have some dusting of what I believe is melted aluminum. If you were to take a shot of the piston, I think you will find the radius going into the combustion bowl is probably more like 1/2" than the 3/16" it is supposed to be. You are melting out your pistons.
The #1 and #2 pistons are most likely to have problems with melting, as the intake manifold 'starves' those cylinders for air. Excessive fuel and insufficient air will cause this overheat condition, but it can also simply be injectors that are running too much fuel or fueling uncontrollably.
My conclusion is the head is ruined. The block is warped and I'm guessing there are at least two pistons that are melted.
I am making an attempt to remedy this vexing problem for injector location and damage to the intake valve and seat. As TDIMeister said, this is far from an isolated issue. All the PD motors, especially ones that are pushed too hard suffer a crack to the intake seat. Your situation is much more severe than normally seen.
I would like to see additional pictures of the #1 and #2 pistons. I would like to know which cylinders the first two pictures are related to.
Feel free to contact me.
