Strange engine rattle

[Loltr]

My TR7 has developed a rattle in the engine (well I think it is the engine).
The sympton is that there is a real death rattle when accelerating tthrough 3000rpm.The sound seems to be coming from the top of the engine.
If gear changes are kept to below 3000rpm the rattle is not there. Also there is no rattle when engine is revved when gears are in neutral.
The engine has done 190,000km and other wise runs strongly.
I thought initially that it was the timing chain and have replaced chain, tensioner and guides.
The problem also seems to be worse when the engine is hot.
I suspect that it may be oil pressure problems. However the oil guage shows a running pressure of around 38psi.
Any suggestions as to what the cause may be or any further diagnostic tests that I can try would be greatly appreciated.

[REPLIC8]

Have you checked for play in the bearing on the viscous fan coupling? I had a similar thing on my V8 and the fan bearing was badly worn. It only made the noise whilst driving along, couldn't replicate it in the garage. I think it was affected by the air flow through the engine bay. Turn the fan and try to wobble it, it should have very little play, mine had a loose point where the blades could be wobbled about 5mm or more. Worth checking before doing engine work.

[rugbyref1]

I agree with the above and on a similar note i had a problem with an alternator causes intermittent noise.

[Hasbeen]

Yep, give it a run with the fanbelt removed, just don't do it for too long.

Hasbeen

[gaz]

Have you checked your timing,
When my electronic ignition got fitted the timing got set wrong it was able to start drive and sound smooth.
However I'd just had my engine rebuilt but under load just when came of the gas to change down I was getting the noise you speak of.
I took my car to the engine builders who re set the timing and happy days followed.