tachometers .... gas vs. diesel

[Bertramp]

Hi folks ... quick question
Is there a difference (aside from the range of numbers) between tachometers for gas engines and those for diesel engines ?
Are they driven differently ?
Are they interchangeable ?
thanks

[thoward]

They differ. The old DDs(71series) can have a gear driven or an electronic setup but it is specific to DD. The gas engine tach would most likely pick up off a coil and could not be used on a diesel.

[BUSTER]

Thoward is absolutely right.Most modern diesel engines send data to the tachometer via opposing magnets on the flywheel and bellhousing or a sender on the alternator

[Brian Degulis]

The Tachs themselves are similiar most are adjustable for the # of pulses per revolution. Gas engines can pick up the pulses from the ignition system since diesels don't have an ignition system the pulses come from. A pulse generator mechanicaly driven from an engine accessory drive, An alternator, A device that counts the teeth on the flwheel or on the newer electronic engines the ECU (computor). If your looking to match a tach to an engine you will need to know the pulses be generated by whatever is doing that and the pulses aceptable to the tach itself.

Brian

[Bertramp]

Engine is a mechanical Cummins 6BT in a 24 Topaz.