240z w/L28 - No Tach Signal??

[Hugh]

I didn't install the engine, so I don't know what they did to the tach signal. I have no tach whatsoever right now. (just bought the car)

 

I'm going to pull the engine soon for my SR20DET, but I'd like to have a tach until then. Can anyone point me in the right direction to get the tach signal from the L28 into my dash?

 

Thanks for being patient with me. I am a newb to the Z, but not a newb to Nissan racing.

 

Oh its a 73 240z, and I was told a 75 L28.

[evildky]

you sure the tach is not broken? my 240 had a burned out diode in it when I got the car, I modified a 280 tach to fit the 240 housing then had to rewire it when I changed to a 280 alectronic dist, I know somewhere along the line the changed from a positive to a negetive signal, guess first you'll need to determine which signal your tach needs then run the wire from the approrpiate side of the coil

[Guest bastaad525]

his tach's not broken, I had the exact same problem when I swapped my N/A 280ZX motor into my '72.

 

 

Unfortunately I dont' have any good news for you, after much asking around both here and at zcar.com, no one was ever able to tell me how to get the stock tach to work. That's not to say there isn't a solution though. I do remember having the reason explained to me as to why it happened though, something about the 240's tach works very differently from just about every other tach out there, basically it works the opposite way.

 

At any rate I finally got tired of it and just bought the cheapest autometer tach I could find for about $50 and didn't look back.

[Hugh]

Thanks guys.

 

I hear that on the aftermarket Tach. I figure thats best for when my SR20DET goes in, anyway.

 

I guess its time for shopping.

[Guest steves280]

Or get a 280Z tach. They are a "normal" tach that runs off the negative side of the coil and work with a Z/ZX ignition just fine. Just run a wire from the post on the back of the tach to the negative side of the coil. If it has aftermarket ignition, you'll have to do some internal mods but they will still work and are stock/fit the dash.

 

I've swapped ZX distributors in 240Z's and the original current tach still worked so maybe it's how they wired it? You have to remove the balast resistor at the coil for it to work as the ZX ignition doesn't use a ballast and also uses a lower ohm coil.