5 inch gauge Britannia Coeur De Lion 70007 under test

Testing out a 5 inch gauge live steam Britannia Coeur De Lion to test new piston valves.
Old valves were a bad fit and the timing was out so a trial of new piston valves made with Flouosint heads sealing on orings to the valve bobbin. The main checks are to see if it seals and to make sure it doesn’t expand to much and seize the loco when hot.