How to determine the clearance and how to supplement the compression top dead center when adjusting the valve of single cylinder diesel engine; No time scale

How to determine the compression top dead center when adjusting the valve of single cylinder diesel engine? Disassemble the nozzle in advance, and find a long cross screwdriver to extend from the hole where the nozzle is installed, which will push it onto the piston head. When you slowly shake the flywheel, the Phillips screwdriver will slowly extend. When the Phillips screwdriver changes from extending to contracting inward, and the intake and exhaust valves are closed, this is the top dead center of the compression stroke. At this time, the clearance of the rocker arm of the intake and exhaust valve can be adjusted. Turning the flywheel counterclockwise is the injection advance angle.