Knocking noise

[keithmr2]

Hi
I've got a knocking noise, i can hear it up to about 2500 revs it almost sounds like it's coming from the inlet manifold . I've checked the valve clearence's they seem fine, i put a seconed hand head on and it been doing it since then. I'll be rebuilding it again soon anyway does anyone know what it could be to save me a bit of time.
Cheers Keith

[Lauren]

tappets? because they are not hydraulic on the 4A.

they normally rattle a little, wouldn't call it knocking though as such, is tooo tinny for that.

[keithmr2]

It's definatley not the tappets, or injectors. Its more of a knock, its stumped me i just hope it will become more apparent when i strip it down.