Cylinder Head Reconditioning

  • Cap and Rod Grinding
    Cleaning & Degreasing
    Cylinder Boring and Milling
    Cylinder Head Services
    Dyno Testing
    Engine Balancing
    Engine Blueprinting
    Flow Bench Services
    High Performance Rebuilding
    Machine Shop
    Rod & Piston Work
    Speed Shop Services
    Valve Refacing
    We use a Sunnen SGM-1500 machine (see below)
  • All guides are checked using Sunnen Dial P310 Valve Guide Gauge Set for taper and trueness
  • All guides are replaced using the .030 bronze Guide Liner, then honed to size.
  • Valve seats are replaced with hardened inserts
  • Valve seats are cut using multi-angle cutter in the Sunnen SGM-1500 giving the valve-to-seat concentricity to industry standard or lower (industry standard is .001 per valve head size; 2.00 valve head should be no more than .002 concentricity)
  • All valve seats are cut exactly the same and also maintain the same height in the chamber
  • All valve seat pockets are cut to the same depth to maintain spring squareness and installed heights (out of square spring pockets cause abnormal valve guide wear)
  • Valves seal bosses are lowered for added lift and re-cut for positive seals
  • Installation of screw-in studs
  • Installation of .500 guides, bronze or cast
  • Installation of beryllium copper seat inserts for titanium valves
  • Pinning or welding for cracked heads (aluminum cast)
  • Installation of push rod sleeves
  • Match cc of all combustion chambers
  • Porting and polishing
  • Checking RMS for proper surface finish
  • Resurfaing heads
  • O-Ringing heads
  • Correcting intake angles
  • Angle milling
  • All valves are re-ground to correct angles and lapped to seats using a power lapping tool
  • All springs are installed to correct spring heights

Sunnen SGM-1500
The Sunnen SGM-1500 is built to handle everything from karts to Winston Cup race engines. It's built with all the features and benefits that assure the best valve seat concentricity of any machine. Optimum speeds mean no chatter and assure superior finishes and geometry, turning out top-quality work, every time.

The Sunnen SGM-1500 is a cylinder head machine provides complete valve guide and valve seat machining. The SGM-1500 is capable of reconditioning cylinder heads to factory tolerances as well as custom machining for high performance engines.


  • Simultaneous multi-angle cutting of valve seats.
  • Precision installation of valve guide inserts.
  • Spot facing of valve guides and bosses.
  • Cuts valve insert pockets - aluminum or cast iron.
  • Drilling and tapping for threaded studs or removal of broken exhaust studs.
  • Bronze guide liner installation and reaming.

Call for pricing and further details.


Mason's Racing Engines

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Contact Us: Mason's Racing 53 Hartford Avenue North Scituate, RI 02857
In RI: 401-934-9877 Toll Free: 1-888-235-1622

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