Pud. You are missing the point. Dan is on the cheap and does not want to buy a compression tester. The tool I was refering to is used to hold the valve inplace when you want to replace the valve steam seal when the head is still on the motor. You get the valves closed, connect the fitting to the air compressor and that holds the valve inplace while you remove the rocker arm, valve keepers, spring and old worn valve steam seal. That is what the tool is made for. I was just trying to give Dan another cheap option to see if his valve was stuck open if he could not find a compression tester.