Piston broken

After getting some great help to get the engine out we continued and removed pistons 2 and 3, the ones showing sign of low compression.

Umm been here before - third time lucky perhaps!

Removing one of the remaining timing chain guides so the chain could be removed. It's tied to the cam sprockets so hopefully the timing won't be too difficult to set correctly later.

I will remove the mount, alternator etc. as I may need to take the block somewhere to get it honed (I'm not sure that I trust myself to do it so the cross hatching is at the right angle). 

Well not a pretty sight. This is piston 3, the one showing signs of wear. The rings are still whole and in place but the piston is broken between the ring grooves. Two bits were ready to fall out completely! The side of the piston is also worn so what's happened? 

The wall of the cylinder is slightly scored but maybe it's enough to use a honing tool?

Now this is interesting, below is piston 2, also showing signs of low compression. Took the piston out, no damage to the actual piston but straight away noticed that the ring gaps were lined up and not at the usual 120 degrees offset alignment. From what I have read it is usual that rings rotate over time so perhaps it's coincidence that they are aligned just now! But this can't be good for compression can it? I'll replace them with new ones and put them back to 120 degrees.

Is it the cross hatching in the cylinder that makes the rings rotate?

I'd like to get the head and valves looked at too just in case there's something that needs doing. Hopefully I'll be able to start putting bits back soon!

Here is another close up of the broken piston. Only the rings were keeping the bits together. Is this the sign of over heating due to running too lean? This injector was showing signs of low fuel throughput.