The V8 Owners Forum -

The pully was loose, so was the bolt, only because the bottom sprocket was missing, so it had nothing to lock up against.

thats a right bugger ian,
hope the pistons and heads are not damaged.

Hi Ian
any idea why the bottom timing chain sprocket broke? never heard of that one before, must have taken alot of energy to break a sprocket axially into three bits, sure it is not the result of somthing else going wrong?
best of luck
Mike

I have no idea why it broke, I think it broke after lifting off from a burn out, so there would be some reversion on the chain on over-run, so I was wondering if the chain climbed a tooth and jammed.
Ive got my engineering hat on at the mo, but untill I can get the engine apart fully any meaningful answer is just guess work, making an educated guess about the chain, this could have easily taken off a tooth, and if it has jammed near the root of the keyway, that is quite a good point to act as a stress riser and break thru the keyway, which is where it has.
I will try and download some pics later, The key is deffo not rounded off, but it has some damage due to hitting bits of shrapnel

Ive taken one head off now, and it appears to have clipped all the exhaust valves, mainly due to the reason being the valves are too big for the cutouts I will do a parafin test tomorrow ust to see what, if any are bent, but i think I will change all the exhausts, just for safety,
The 4 pistons I can see dont appear to be too damaged, with just a small witness mark on the edge of the cut outs

Sounds like it may not be too bad at the moment then mate?