Just bought a V8 '95 Disco, 3.9. I noted it had a slight knocking sound , which appears to be from top area of engine. It goes when revs increase above say 1200 to 1500 rpm, engine is quiet otherwise. I have heard that LR V8's can get cam knock due to some slack in positioning of the cam and LR issued tech note on this. Anyone had this and if so how do you fix it? What happens if you dont!!