4PISTON Flywheel Bolts. 4P Flywheel bolts are stronger and reusable, unlike the OEM flywheel bolts. They are also the proper length for all aftermarket crankshafts, which frequently have shallower threaded bolt sections. Say goodbye to loose flywheels, ruined crankshafts and clutches, and stop buying new bolts every time you unbolt your flywheel.