Slipped cylinder liner??

Any more ideas on how to diagnose this? How can I tell noisy tappet apart from other problems?

piston would be engine speed tappet half,i had a piston that deformed when hot and would tap

i would look at the rocker arms first as it could be the cups rattling free

Looking at some exhaust manifold and coolant leakage problems first, when that's solved I'll start her up and record the sound, maybe that helps.

It's definately half engine speed, so it has to be something to do with the valve train. Some more background, the engine's a 4.6 V8 and has done approx 250k km.

I think I can either look at just the rockers first, or replace rockers+arms, cam followers, cam shaft and timing chain (it's probably a good idea to replace the chain anyway at this mileage?)

250km proberly fubar if it is the original item!

250k km.. that's 170k miles (iirc). Should not be fubar I think? At least it doesn't drive like it is. It's just a noisy when the engine gets warm

i referre to the cam anything over 70,000 and they are 50% on the way to worn out most engines i rebuild have less than a 100,000 miles

Ah I thought you meant the engine was fubar Current plan is to leave the heads on for now, and replace camshaft, tappets and rockers