If you want to measure oil perimeters accurately, dispense with the clock & the oil clock & fit a proper oil pressure gauge & temperature gauge. There’s something odd about the existing gauge if you have a VVC engine, the system doesn’t much care for a proper gauge, so I left mine connected & tucked it behind the dash promising to sort it out later. This later I alluded to is an unspecified time, much as it was two years ago when I fit the instruments.