gas to diesel swap

[justnuts]

have a late 60's cabin cruiser that was was originally powered by two 292 Chevrolet inline 6 cylinder engines. I have replaced them with 2 ford senator diesel engines have them running now and every thing works except the tachometers. Anyone have any idea on how to hook them up?

[GordMay]

Greetings and welcome aboard the CF, justnuts.

/w Flywheel Proximity Pick-Up ? ➥ http://www.cruisersforum.com/gallery...r&imageuser=79

[Capt Nemo]

Originally Posted by justnuts

have a late 60's cabin cruiser that was was originally powered by two 292 Chevrolet inline 6 cylinder engines. I have replaced them with 2 ford senator diesel engines have them running now and every thing works except the tachometers. Anyone have any idea on how to hook them up?

Hi Justnuts

Unfortunately, you will need to replace the existing gasoline engine tacks with diesel engine tacks. The gasoline engine tacks have an electric pick-up on them, where-as, the diesel engine does not. This is how it has been explained to me.
I did a similar swap a few years ago.

Good Luck
Capt Nemo

[justnuts]

The new engine are inline 6 cylinders as well, but diesel engines have no ignition coil to hook the tachometer sensor wire too. I'm thinking it must get its signal from either a crank sensor or from the alternator, but i don't know which do you remember where your tachs got there signal from?

[Sailmonkey]

Originally Posted by justnuts

The new engine are inline 6 cylinders as well, but diesel engines have no ignition coil to hook the tachometer sensor wire too. I'm thinking it must get its signal from either a crank sensor or from the alternator, but i don't know which do you remember where your tachs got there signal from?

Tach signal can come from either of the two sources you just listed. If the bell housing has a threaded hole and a magnetic tooth on the flywheel you'll need to source the parts to install a mag pickup there. Otherwise a signal is provided by the alternator, assuming it's wired to provide said signal.

[GordMay]

See ➥ Troubleshooting Teleflex Tachometer Gauges

[phorvati]

There is a way to do it but you need to be handy with fine tip solder iron and understand how frequency to voltage converter ICs work.
Two years ago i went from Atomic 4 gas engine with Coil sensor based analog tachometer, to westerbeake 1-108 with magnetic pickup. My main reason for doing this besides $$$, was that i wanted to use my old instrument panel and diesel tachometers do not come in 2-1/8" diameter. I had no room for a 3" or 3.5" hole on my instrument panel.
What i ended up doing is taking the tachometer unit apart and modifying the circuit board to work with magnetic pickup based signal.
Then calibrating display unit under various RPMs using a separate RPM meter. Most tachs have a potentiometer(calibration knob) in the back to use a fine screw driver and adjust the needle deflection.
Saved me few hundred dollars and more importantly, space.
Let me know if you're interested on how to do this.