Before
Original customer-supplied valve stem with Ra 5.49 µin roughness before polishing.
Second customer sample showing Ra 5.13 µin prior to process optimization.
After
Initial Bel Air polishing trial reduced Ra to 1.90 µin—already outperforming the baseline.
Refined polishing process brought Ra down to 0.73 µin for a superpolished finish.
Objective
Bel Air Finishing was tasked with automating an ultra-polish solution for high-performance engine valves to enhance operational efficiency and meet precise surface requirements. The goal is to achieve a consistently polished, high-quality finish that improves the performance of racing engine valves.
| Industry | Automotive, MicroTech |
| Part Description | Racing Engine Valves |
| Fabrication Method | Ground |
| Material | Titanium |
| Process Technology | Burnish, Superpolish/Ultrapolish |
| Equipment Type | Automated Finishing, Drag-Spindle Finish, Centrifugal Barrel/Harperizer, Dry Finishing |
Solution
Bel Air evaluated several high-energy polishing methods to improve the surface finish on racing engine valve stems—achieving results beyond what cylindrical grinding could offer. The initial process brought Ra down to 1.90 µin, already an improvement over the customer’s 4.25 µin average. After refining the process, Bel Air achieved a superpolished finish of 0.73 µin—an 80% reduction in surface roughness.
These results were achieved using either a Mini Hoppa Harperizer or the AutoHone™ Robotic Reverse Drag Finisher. Each option offers different advantages depending on part geometry, production goals, budget, and the level of automation required. The project highlights Bel Air’s ability to develop scalable, high-performance finishing processes tailored to customer needs.
If you are unsure what equipment and media you require to achieve your desired surface finish, then send us your part, and we will evaluate it and provide you with a metrology report.