Q: Dial Gauge Timing .. what does this mean?
A: Dial Gauge Timing is a method of timing the fuel injection in diesel engines. This involves placing a dial-gauge into the pump assembly and measuring the pump plunger lift .. usually from 0.5–2.0mm. The point of lift may not be the actual injection timing, depending on whether the pump has any pre-stroke in the design. The engine is hand rotated back 90 degrees before compression TDC on the cylinder to be timed and then hand rotated usually to TDC. At TDC the dial-gauge is read for the recommended lift measurement.
Using the dial-gauge method is often difficult in modern compact engine compartments due to limited access. (This is a bit of an understatement!)