Just a query about 'polishing' the head? You don't mean the inlet manifold/port do you? Because this is a sure way to reduce flow and reduce the chance of fuel staying in suspension! Defiantly not good on ether account! Improving the combustion chambers surface finish is always a good thing... and polishing the exhaust port or using a ceramic coating can defiantly give good results. But the Alfa twin cam head has a very short port in the head reducing the effects of heating from the exhaust gas - which may make this quite a bit less effective compared to a BMC A or B series engine for example.
It was me, I'd leave the ports alone and getting the valve seat widths and angles sorted - good for flow, reliability and cheap too!
Just a note on valve springs - can't help with the alfa engine but its worth using the recommended springs for the cams for the RPM you'll be spinning the engine up to. Over springing the valves only wastes power though friction and puts greater stress on the valve gear. Probably not such a problem with over head cams but if you're talking push rod engines...still, every little helps!
Just my couple of pence worth! Toby
It was me, I'd leave the ports alone and getting the valve seat widths and angles sorted - good for flow, reliability and cheap too!
Just a note on valve springs - can't help with the alfa engine but its worth using the recommended springs for the cams for the RPM you'll be spinning the engine up to. Over springing the valves only wastes power though friction and puts greater stress on the valve gear. Probably not such a problem with over head cams but if you're talking push rod engines...still, every little helps!
Just my couple of pence worth! Toby
