Megasquirt 4.2 ABH V8

Why is the engine dead?

the pistons melted into the sides of the bores and the engine went BANG! its on youtube http://youtu.be/ID5D728VGyw

The previous owner of the car had run it without water I think and melted the insides. The new AEW is perfect, I have just changed all the valve stem seals, and am doing a cambelt change. Hopefully I will get its started today.

Ahh. You didn't opened the engine?
Turbo with stock CR? Oha :-D

Do you have pictures of the damage?
Melted piston is normally a lean mixture or a lot of knocking.
Without water it's more or less a seized piston.

Such much white smoke?

yes, lots! and bangs, the pistons melted into the block

Your description sounds not realistic to me!

If a block went dry, maybe the pistons melt to the cylinder - then you never will run the engine again... and why the white smoke?

More reasonable seems to me, headgasket damage -> water in oil and/or combustion chambers (white smoke) -> not enough lubrication -> piston damage.

Well, I know how it works with a dry block in front... 7 Years ago... 50km, including traffic jam (half an hour in Zurich rush hour) and highway (120km/h and more) and at the last 10km a intensive inclination... replaced a hose, filled in coolantwater - it runs till bevore i come from work... 110tkm later...