Disco V8 accessory bracket bolt thread Imperial?

[tailslide]

It looks like the bolts for the LH accessory bracket (ACE and PAS pump) are UNC 3/8 16 tpi.

I'm about to install heli coils as the threads in the head have been pulled/sheared out. I was expecting to see a metric thread. The current bolt threads are also mangled so I have new bolts on order. I thought I would ask here before I go and install the heli coils, not wanting to wait till the new bolts arrive from the UK, none in Australia...

Cheers
Ron

[p38arover]

I think all the engine threads into aluminium are UNC. There might be some UNF elsewhere.

[bee utey]

The 4.0 D2 engine that I wrecked had all UNC threads into the block and heads. Metric threads are found in all the other castings where parts attach to them. That is why they are all back convertible to the first Rover V8.

[tailslide]

Thanks guys for the confirmation. My current bolts are stretched, cross threaded, and full of aluminium... So it was a bit hard to accurately determine the thread, but I was betting on UNC 3/8.


I suspect that previous head gasket changes these bolts were done up by a monkey with a breaker bar and not a torque wrench. You may get away with this on a cast iron head but not with aluminium.


Cheers
Ron