elec. ignition with original 240 tach

[flomastr]

hey,

maybe stupid question for you smart guys, but if i use electronic ignition from a 280 on an original 240 tach, will it work.

if it won't, how can i use the original tach (or at least tach face) in the dash??

btw, its a '70 240 with i28 block, 240 heads, electronic ignition.

thanks for any help....

[Greygears]

No. Your 240Z - 260Z tach will not work With an electronic ing. In all 240's and 260's with points in the distributor, The positive 12 volts from the Ign. switch went through the tach on its way to the positive side of the coil. Very strange. Most tach's take thier pulse signal off the negitive side of the coil. When Datsun switched to electronic Ign. in 75', with the 280Z, they went to a regular tach that reads off the negitive side of the coil. You can't run the electronic system through the 260's tach because there will be too much fo a voltage drop to run the system under load. thats why Datsun uses a relay in this system, to supply max current flow to the electronic box (and it likes a lot). Your answer is to install a 280Z tach and run it's pickup wire to the negitive side of the coil. And make sure you install a Ign. relay (Raido Shack sells a 30amp automotive relay that works fine) that will take 12 volts from your starter motor battery post and supply it directly to the positive side of the coil.