Valve Seat Tooling & Valve Seating Cylinder Heads


Advanced Cutting Tool Systems Valve Seating Cylinder Heads provide exceptional tool repeatability and are compatible with all valve seating machines. Advanced Cutting Tool Systems offers in-house, turn-key capabilities for superior quality assurance.


  • Finish Seat and Guide
  • Rough Pocket
  • Porting Tools
  • Spring Seat
  • Freeze Plug
  • Seat Pocket

Cylinder Heads

Typical Cylinder Head
Valve Seating Sequence


In-House Turn-Key Capability

  • CAD/CAM Engineering
  • CNC Manufacturing
  • Certified Quality Systems
  • 24 Hour Service Center


First Part / Good Part

Tool Change Repeatability

  • Precise Concentricity
  • Superior Seat Finish
  • Rigid Construction
  • Precision Balanced
  • Indexable Inserts
  • Replaceable Bushing
  • Adjustable Sizing
  • Quick Changeover
  • Compatible With All Valve Seating Machines
  • Improve Tool Life
  • Reduce Cutting Force and Horsepower
  • Increase Productivity
  • Lower part Costs

The valve seat in an internal combustion gasoline or diesel engine is the surface against which an intake or an exhaust valve rests during the portion of the engine operating cycle when that valve is closed. The valve seat is a critical component of an engine in that if it is improperly positioned, oriented, or formed during manufacture, valve leakage will occur which will adversely affect the engine compression ratio and therefore the engine efficiency, performance (horsepower), exhaust emissions, and engine life.

Valve seats are often formed by first press-fitting an approximately cylindrical piece of a hardened metal alloy, such as Stellite, into a cast depression in a cylinder head above each eventual valve stem position,[1] and then machining a conical-section surface into the valve seat that will mate with a corresponding conical-section of the corresponding valve. Generally two conical-section surfaces, one with a wider cone angle and one with a narrower cone-angle, are machined above and below the actual mating surface, to form the mating surface to the proper width (called "narrowing" the seat), and to enable it to be properly located with respect to the (wider) mating surface of the valve, so as to provide good sealing and heat transfer, when the valve is closed, and to provide good gas-flow characteristics through the valve, when it is opened.