Bad news.
The workshop stripped the engine down today and found a few problems. The Cam chain was fine and well oiled. The balancing chain was very slack but well oiled.
When the mechanic lowered the cam chain by removing the wheels he found a nut/bolt sheered off that holds the chain guide into place.
There is minimal room between this fitting and the car body work to get a drill in place to drill out the sheered off bolt. Even so he said you could not guarantee a straight drill in and risk ruining the thread and therefore it would then need a new head.
He is now pricing up to remove the head or lift the engine to deal with the issue. Anyway it appears the noise was the balancing chain as it was slack and the cam chain hitting the guide. Its going to be expensive but sheer luck the chain didn’t snap as the guide and the sheered off bolt were hitting the cam chain.
:thumbdown:
