Tachometers

VDO tachometers (rev counters) for petrol and diesel engines. Diesel scales of 3 000 and 4 000 rpm suit trucks, tractors, generator sets and boats; 6 000, 7 000, 8 000 and 10 000 rpm suit petrol and performance engines. Sizes are 52, 80 and 100 mm across the Cockpit International (12 V or 24 V), Cockpit Vision (12 V, with stud and bracket mounting on the 80 mm) and SingleViu (12/24 V) series.

A tachometer reads engine speed from a pulse signal. On a petrol engine that is usually the ignition coil; on a diesel it is the alternator W terminal or an inductive speed sender on the flywheel housing. Electronic VDO tachometers are set to the number of pulses per revolution when they are installed, so note the cylinder count or the alternator ratio before you start. Speed pulse senders are under Senders & Sensors > Speed Sensors.