I need a tach and have a question

[red_dog007]

Will a 1975 Datsun 280z Tachometer work just fine in a 1971 Datusn 240z? Mine isn't reading correctly, and is getting stuck so I am in the market for one that works.

My tach, the yellow line starts at 6.5k with red line starting at 7k. This one, the yellow line starts at 6k with red line starting at 6.5k both showing a max of 8k.

I hope that this one works. I like that this ones yellow line starts out at 6k as the peak HP ends at 5.6k.

[EScanlon]

Nope.

The 71 uses what is referred to as a "4-wire" tach and the 75 uses the "3-wire" tach.

E

[red_dog007]

So then I basically have to try and find a 240z tach. Are there any oem after market ones?

[Arne]

You need an early 240Z tach. They used the four-wire tach in '70 and '71, and the three-wire in '73. I'm not certain about '72s.

[ktm]

You can use a 1975 tach in your 240z. However, it is not plug and play. I am swapping in a 280z tach as well with my build, as the tach signal provided by my EMS would require a signal converter to work with the 240z tach. I figured I might as well eliminate my old inductive loop tach for a modern design, since I am converting to coil-on-plugs as well.

The 240z tach uses an inductive loop off the positive side of the coil. The 280z tach uses a single line off the negative side of the coil. If your car is not bone stock and you do not care about not using original parts, you can use the 280z tach but you'll have to do a little bit of wiring.

Chances are that the plugs will be different as well. I know that with the 280z clock, voltmeter and oil pressure gauges I am installing, the lights are incorporated into a common plug with the gauge inputs. The 240 gauges kept the lights separate.