piston on crack!

[85-m1028]

I just pulled the heads off my old motor to find them in very good condition "no crack visible between the valves at all!!" but upon inspecting my block found the rear piston cracked severely and a hairline running through the front piston "passenger side" I have yet to pull the head on the other side?? Is this only caused by poor injectors or are there other factors?? how can this be avoided on my hmmwv 6.2 that I will be putting in??

[john8662]

Pistons crack for several reasons, the biggest being heat.

So if I understand you correctly, you pulled the passenger side head. This will have cylinders 2,4,6,8 the cylinder closest to the front of the truck is #2 and the back is #8. So #2 is cracked?

[85-m1028]

both #8 and #2 are cracked #8 being the worst splitting down the center, down and around the dish, #2 has a hairline in the middle going about halfway into the dish, *when the oil cap was removed a steady stream of white smoke billowed out, piston crack explains that. *glow plugs had white coating on the ends, looks like calcium and were partialy swollen. "brand new about 2 months ago, autolite #1110's"