Exhaust Valve Spindle and Seats

Full recondition of piston skirts including removal of old wear rings, installation/expanding of new rings and final machining to original specifications.  Full reconditioning includes machining or Piston Seat Areas and Rod Seat Areas.

Our Capabilities include manufacturing of new tube seats, new tube bundles and final fitting and expanding using special tools back to original manufacturer specifications.



Piston Crown

Piston crowns are fully reconditioned from start to finish in our State-of-the-art Houston facility where we monitor all processes from pre-machining, to welding, to plating and finally the precision grinding. The piston crown is pre-machine using CNC equipment to remove all cracks on fireside face and entire groove area. Then units are placed in Fully automatic robotic welders that completely build up area into on solid pcs. Then units are stress relieved and placed on Vertical CNC lathes and an automated process machines the piston and grooves to makers specifications depending on model number and prepares the unit for plating of ring grooves. This CNC process ensures that every unit comes out identical and always to specifications. The piston crown is then prepared for the plating process which is conducted with all electronic and controlled equipment using the latest rotating plating technology. After the desired plating thickness is achieved the piston crown then travels to the automated precision grinding machine. During this stage the grooves are grinded using CNC and digital equipment which ensures the finished product is within maker tolerances and specifications.

A. Piston Crown standard full reconditioning procedure


  • Removing of all accessories
  • Grit blasting and cleaning
  • Visual inspection, mangnaflux crack test
  • Pre-machining, welding and final machining of ring grooves area and combustion face (up to 6mm).
  • Welding of combustion face with Inconel layer (option)
  • Stress relieving
  • Chrome plating of the ring grooves.
  • Final grinding to original dimensions
  • Internal cleaning of cooling water bores (if applicable)
  • Final inspection and hydro test
  • Fitting of removed and/or renewed accessories
  • Rust protection and packaging

The reconditioning of Exhaust Valve Spindles and Seats is done using fully automatic CNC equipment and automatic Robotic Welders to ensure that the process and finished product meets and exceeds original makers standards and specifications.


Exhaust Valve Spindle standard full reconditioning procedure


1)  Sandblasting

2) Testing and inspection of markings to determine is Stellite type or Nimonic

3) Machining of the seat surface

3) Machining of fire side face (up to 6mm)

4) Preheating

5) Gradual build-up of fire side face using original material (up to 6mm)

6) Gradual rebuilding with Nimonic 80A (for Nimonic Type) or Stainless steel with Stellite #6  

    in way of seat area (for Stellite Type)

7) Gradual cool down and stress relief after all welding procedures

6) Final machining to makers standards

7) Dye check for crack detection on completion of work

8) Grinding of the seat to makers tolerances

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