Valve Opening Comparator & Transfer Gauge
This is a straightforward tool that performs a VERY VITAL job in flycutting pistons. It is very critical that the valve relief in the piston is the same angle as the valve in the head ~ especially on high RPM applications where piston-to-valve clearance is at a minimum.
Usually, if you float the valves and they hit the piston squarely, little damage is incurred. However, if you hit a piston with the EDGE of a valve, it will always bend the valve, and many times, will break a valve head off (which is a disaster, especially at high RPM). You can’t take for granted that the existing angle on the piston is correct, especially after angle milling, etc.
This tool is simple to use and a lot less time consuming than clay. Simply:
- Set the tool on the cylinder to get the valve angle.
- Lock tool at this angle.
- Set the fixture on the piston to check piston relief angle.