K Series cylinder head page
Below is a standard out of the box K16 cylinder head, note the small valves and rough finish around the valve seats where the inserts dont align properly. Note also the valve guide and boss protruding into the inlet port and the comparatively wide valve seats. There is also 'pocketing' around the valves and a degree of shrouding at the corners of the combustion chamber.
Std. K16 Cylinder head
This is a modified K16 head using the Paul Ivey 30mm inlet valves and 26mm exhaust valves in the standard seat inserts, note the smooth contours around the valve seats which are now thinner and the abscence of the protruding guide and guide boss in the ports. The combustion chamber has been modifed to remove the pocketing on the standard head and to unshroud the valves in the corners of the combustion chamber, the head has been skimmed a little to bring the CR up to a little over standard since opening up the combustion chamber lowers the compression a tad. The valve throats have been enlarged by 3mm in diameter on the inlet side and 2mm on the exhaust side. This cylinder head flows better than a VVC/VHPD head throughout the lift range. The ports although not that visible here have been enlarged by 4mm or so on both inlet and exhaust which brings their area into line with the VVC/VHPD casting, This head belongs to Johnty Lyons and is currently fitted to his Caterham Superlite.
Modified big valve K16 Cylinder head
A standard VVC/VHPD head, note that although the combustion chamber is a better design, the valves are 'pocketed' and again there is poor aligment between the seat inserts and the valve throats. The ports although larger still have a protruding guide and boss and the throat area is poorly finished. Having said that the head is a big improvement over the standard K16 head.
Std. VVC/VHPD Cylinder head
Modified VVC/VHPD cylinder head
Below is the same head after I have ported and reworked it, note the pocketing round the valves has disappeared as has the valve guide boss and all the misalignment between the valve seat inserts and the port/throat, the throat area has been enlarged considerably on both inlet and exhaust as has the port area.
Combustion chamber and throats