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CNC Valve Seats

Newen Contour BB Seat Profiling MachineThe valve seats are an extremely important feature of any cylinder head. The quality and precision of the valve seat geometry determines how well the valves seal against gas pressure, how fast heat is transferred away from the valve heads and the rate at which the mating faces will wear in service.

Apart form these thermo-mechanical factors what is also significant in a high performance engine is the influence of the seat geometry on gas flow behaviour in what is a critical area for the gas exchange processes. Continuous development using air flow rigs and engine dynamometers has shown that real gains can be achieved by paying careful attention to this area.

It has been found that conventional 3-angle seat cutting machines have limitations in terms of cutting suitable profiles for performance as well as in the quality and consistency of the valve seats so produced. This is particularly true when fitting new, hardened, oversized valve seat inserts for big valve conversions.

Ford Zetec Valve Seat MachiningTo compliment its own leading-edge port machining process, Ultimate Performance has invested in the current state-of-the-art valve seat cutting technology and has installed a NEWEN Contour single point CNC machine. This uses a single point cutting tip radially and vertically positioned under computer control. Many roughing passes are automatically generated to remove material at high speed and with high accuracy. The final cut is a shallow, slow-feed pass and concentricity to the valve axis is ensured with a close fitting tungsten carbide pilot, pneumatically auto-centred and clamped at the beginning of each cycle. Seat height is controlled with an electronic reference probe.

All Ultimate Performance CNC heads feature CNC profiled valve seats but a seat cutting and seat replacement service is also available for those wanting the best at engine rebuild time. Please see the Engineering Services page for details.