I checked the valve lash on my A12 after I discovered that the exhaust lash being set at .010 cold was too tight and was causing the valves to burn. When I set them at .010 In. and .012
Ex. cold and checked them after the motor had warmed up, they were at .012 In. and .014 Ex. The exhaust valves just weren't sitting on the seat long enough to cool properly and they would
get too hot. This is the limiting factor in valve adjustment as you will want the lash as tight as possible to get the full use of lift and degrees on the cam lobe but loose enough to give
the valve enough time to cool itself. Every motor is a bit different and has its own quirks. Sometimes it takes burning and breaking parts to find the optimum settings for your particular
motor to get its full potential from it. I found mine on the A12 motor the hard way.