Summary

What does a port and polish mean on and engine? So this is a term that's applied to modifications on the cylinder head. Porting is a case where we're altering, removing material to alter the flow through the intake and exhaust ports on the cylinder head with the intention of improving the air flow in and out of the engine. 

00:00 - Marco has asked what does a port and polish mean on and engine? So this is a term that's applied to modifications on the cylinder head.
00:07 Porting is a case where we're altering, removing material to alter the flow through the intake and exhaust ports on the cylinder head with the intention of improving the air flow in and out of the engine.
00:19 And when this is done, generally the ports will also be polished.
00:23 So the rough cast surface is removed.
00:26 Polishing is a little bit misleading because we're actually not trying to achieve a mirror finish.
00:31 That actually, believe it or not is detrimental to air flow.
00:35 And what we want is a slightly rough surface finish and that reduces the boundary layer of air right on the outside diameter of the port, and by reducing the thickness of that boundary layer we actually get an improvement in the air flow through the port.
00:49 So that's a little bit beyond the scope, I don't really class this as engine building itself, it's a very specialist task.
00:55 And what we would recommend is that that's left to a specialist cylinder head modification company who know exactly what they're doing.
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