[Mk2] [NA] Bad ratlle / tapping noise when driving

[**toyota-mr2**]

Hi all.

I have a really worrying rattle which seems to be coming from the top of my engine when you rev the car or drive it.

The sound sounds like a bolt or something being bashed about very fast or like a drill when it locks and chicks.

Any ideas because its worrying me.

Thanks.

[Quigonjay]

is it a constant noise that rises and drops with the revs?
possibly just worn shims if so
most older models do have a bit of a rattle