Hi iv recently bought a series 2 as a project, it's had a 1.8 zvh conversion done and when driven normally everything seems fine but drive it for any kinda distance at 70-80 mph the tappets get really loud, leave it for 5 minutes it goes away a bit but soon comes back, previous owner said he took it to a garage who told him it was the oil pump starting to fail, does this sound right to you guys I don't really know a lot about these conversions so have no idea if he's right or not so thought I'd ask you guys that know what your on about lol, if you drive the car at 50 ish mph this doesn't seem to happen, the car has also had efi conversion as well if that makes any difference and the guy who had it ran 10-40 oil in it, any advice would be great fully appreciated,