I want to start a debate - a friendly one please! I say that as with many tech topics people have very strongly held views based on personal experiences / sacred texts(!!) and I'm interested in hearing them all, without a potential virtual punch up! Having adjusted my clearances a couple of Ikea now on my new engine, I notice that the stock quoted clearances for L28 in Haynes / FSM still sound a little tappety. A number of other owners at Goodwood pointed that out too. Also I am finding that on my new cam, the lifting bits are shiny but the base circle bits are still totally virginal - i.e. I don't think they are connecting AT ALL with the rockers. Is this how it should be!? I was under the impression there should be some small wear on the base also. BTW when adjusted and fully tightened, not being an expert, I always use feelers that are .001 over and under to double check it's within +/- a thou. I adjusted on hot and cold engine - while some strongly believe that cold setting is a waste of time, I wanted to play safe and check both scenarios. I have read that too tight a clearance can increase wear on cam/rockers + burn exhaust valves; and too loose can potentially damage valves / seats due to the valves slamming into seats rather than gently "coming off the ramp". So what is the wise counsel on this based on your experiences / reading? Does one stick with stock clearances regardless of the cam or get tighter on higher lift cams!? Also does oil viscosity have an effect on this? Tighter for thinner oils looser for the thick ones!?