04/09/2026
Re-machining valve seats on 3 Skinner DV-3 upper cylinder heads for V***r Motive Company using an original Skinner seat cutter and a new arbor guide manufactured by Northwind Composites. These heads had worn and corroded valve seats as they had a very long run (built 1966) and have been out of service since 1982. The tool upgrade was designed from a verbal description by my Skinner technician mentor, Al Mattichak, in a phone conversation shortly before he died- unfortunately his modified service tool got scrapped, but there were multiple cutters for this size head in my stock. The cutter is designed to face both valve seats simultaneously and is also guided by the bores, however, this and machining them horizontally was found to be problematic. The stand to orient the valve bores vertically and lifting lugs were also designed and fabricated by Northwind/VLC for this project. You can see a valve was blued-in to verify both seats contact. From this point, the valve to be used is lapped into the seat. If it is a free seat valve, this is done with a shim for expansion from heat and if it is a later resilient seat valve (we have made new ones for this project) the lower valve face is skim cut afterwards. One of these heads will initially be used on the new TRV-1 single-acting research engine.
