Due to the extended forces placed on race engines, regular refreshes are strongly recommend. We will be able to tell you how often we recommend for different makes and specifications.
During our refresh process the engine will be stripped down to individual components. Every component will then be assessed, identifying damaged or worn parts which will need to be replaced. Plasti-gauged to check clearances and the correct shells will then be selected. Cylinders will be honed, if necessary, to allow proper breaking in of new piston rings.
Valve seats can be re-faced and valves can be lapped where applicable.
Valve Clearances will be checked and re-shimmed where applicable.
Skimming the cylinder head is a method used to increase the compression ratio within the combustion chamber. Careful measurement is necessary, to ascertain the desired amount of material to be removed. The skim process itself is relatively cheap.
Once skimming is done the correct thickness head gasket can be fitted to control Squish.
The squish is the clearance between the piston and cylinder head. Very important.
A Standard engine will have a generous clearance for manufacturing safety.
Flow / Porting
Flow or porting work to the cylinder head is used to increase the efficient flow of gases into the chamber and out of the exhaust port into the exhaust system. There are various different methods that we can employ, ranging from simply matching the valve seats to port throat to filling and re-profiling the port.
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 the seat 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.
The standard assembly clearances of a factory standard gearbox can vary. A lot.
We can adjust this by using manufactures optional shims or making our own.
Reducing excessive side-play also increases the depth of engagement.
This result in cleaner, faster shifts which also has the benefit of improving reliability.