Head Work

Skim

Skimming the cylinder head is a method used to increase the compression ratio within the combustion chamber. Although careful measurement is necessary to ascertain the desired amount of material to be removed, the skim process itself is relatively cheap.

Skim (Special)

During some of our supersport tuning work, a special skim can be employed. This involves the use of a CNC mill, allowing us to pocket the squish area. This can be an essential asset when the correct thickness 'head gasket' or 'base gasket' are no longer available.

Flow/Porting

Flow or porting work, to the cylinder head, is used to increase the flow of gases through the ports, into the chamber, and out of the exhaust port, into the exhaust system. There are various different methods that we can employ, ranging from simple matching of the valve seats to the throat of the port, full conventional gas flowing, or high velocity port work adding material to the port to reduce the size and increase the velocity.

Matching and Cutting Seats

Standard valve seats are sometimes inconsistent in seat height and width. Re-cutting the seats using diamond facing tools allows us to match all of the seat widths, and remove the inconsistencies from manufacture. We can also undertake a full re-cut of seats, to match their height across all four cylinders. This will ensure more consistent compression ratios, and will also allow for tighter tolerances in piston-to-valve clearance to be used.

Squish

The squish is the clearance between the piston and the cylinder head. Standard engines have large squish clearance, to compensate for machining tolerances. We can measure the squish clearance, and use this measurement to select a thinner gasket to reduce the clearance and increase the compression ratio (this is the only method that can be used to increase compression on a superstock engine).