The process of reconditioning Piston Crowns.
Each Piston Crowns which enters our workshop for reconditioning is treated as discribed in our General Procedure:
Preliminary Inspection.
During the complete premachining of the piston, all cracked and burnt areas are machined away. Lifting holes are drilled out. We try to keep as much as possible landing material between the grooves
The grooves, crown and diameter are welded semi-automatically using the submerged arc process.
1. If the piston crowns are badly burnt away, thery are rebuilt using welding material compatible with the original base matal. This ensures that the heat transfer properties of the original design are retained. Application of a special thin heat reflecting layer of high chrome alloy steel completes the welding of the crown.
2. In the case of all-steel pistons the ring grooves can be reconditioned by one of two methods. a) Hard face welding b) Welding using the original base material, followed by chrome plating.
The piston and seating surface are finished in accordance with the specification of the manufacturer. If the piston is to be chrome plated, the grooves are machined oversized. New lifting holes are drilled and tapped. The piston and seating surface are finished in accordance with the specification of the manufacturer. Piston crown grooves are reconditioned with the guarantee that the exact profile of the crown and the diameter and groove area are obtained.
After refurbishment every piston undergoes the following tests:
1. Inspection of the inside and outside for cracks,
2. Pressure testing in accordance with the specifications of the classification societies.
All items are checked on the Master Check List