Whitehead Performance N42
N42 Head ported by Whitehead Performance in Ontario
Un-shrouded and polished combustion chamber. Bowls are both very polished
Exhaust Port: note the shortened exhaust valve guide and reduced pile of
aluminum. An end mill from a milling machine on a drill press can do that.
Exhaust port detail. Median is bowed around water passages. Look at the coarse
machine lines
Intake Port and valve guide. It has been shortend or a shorter guide installed.
As well, the aluminum build-up around the guide is nearly gone!
Intake port and short side radius. Not so polished near the roof
Rebello N42
Rebello Porting Job (Intake) Very smooth but no changes to valve stem, just the
aluminum mountain around it is reduced and blended.
Rebello Porting Job (Intake)
Rebello Porting Job (Intake)
Porting N42 from a Japanese Site
Cross Section of an N42
L28 Cut-Away exhaust port and cooling passages
L28 Cut-Away exhaust port and cooling passages
L28 Cut-Away intake port and cooling passages
L28 Cut-Away intake port and cooling passages. Boring in with a 40mm hole cutter
at 15° should accomplish the above. However no details of side water passages
are shown.
Port Details
Intake Before & After
Exhaust Before & After (look at the base of the valve seat where it has
been blended with the port wall.
Valve Job
E88 Head on big bore
Polished and Ported E88 (note the bronze intake
valve seats)
Polished and Ported E88. Very Smooth Chambers and
relieved valves.
