Datsun 510 tachometer wiring question / 2 different tachs

[Retro Wave]

Ok so I am trying to help my father in installing a Tachometer on his 1972 Datsun 510. He has two available and I did read some of the wring diagrams but they sometimes contradict one another. I know its a basic "plug and play" thing with the factory plugs but I am confuse with the white wire. Im i suppose to just keep it loop like this as shown in picture? one of the diagrams said to connect from tach white wire  - to the coil positive - going back to white wire. another said to connect it to the ballistic resistor's black with white line wire. 

 

my other question is if you look at the two tachs one is wired differently and has an extra black with green line bullet connector and no white wire in sight. is the bullet connector the white wire that goes to the positive?

 

I don't have a blue cable on my car, they are green, black with a  green line and black. The tach with the bullet connector - the two spade connectors are connected onto the lightbulb wires, is that also correct? (forgot to take picture)

 

It looks like a very easy process but Im not sure about the white wire ( how to  connect it positive or negative) vs that black with green line bullet connector wire (where its connected to?)

 

 

 

 

 

 

[Retro Wave]

ok i think i found something on this site: http://dimequarterly.blogspot.com/2011/08/tech-how-to-510-factory-tachometer.html

 

I guess i'll got with the modern tach with the signal wire (black with green line) going to the negative side of the coil. everything else is connected together with the three pin connector lightbulbs. I just wanted to know what was the right way of connecting this and if i  was missing something from one or both of them and if the white wire is suppose to be loop like that and not connected somewhere like on the screw thread shown in picture. 

 

I did read this as well which is very useful but got confused a little and had to re-read it multiple times to try to get it and im still thinking (confused) about it

http://elfecc.no-ip.info/510/Tachometer/Simplified_Tach_Hookup.htm

[john510]

The one with the two white wires has had the bullet connectors cut off of it i think.I have one of each tach,a 3 wire and a 4 wire.One is inductive and i can't recall what the other is called.It should wire directly into the wiring harness in the dash.I think all 510's had the wiring for the tach in the dash whether it came with a tach or not.

[dgi]

3 hours ago, Retro Wave said:

I did read this as well which is very useful but got confused a little and had to re-read it multiple times to try to get it and I'm still thinking (confused) about it

http://elfecc.no-ip.info/510/Tachometer/Simplified_Tach_Hookup.htm

This write-up is specifically for the tach you have with the white looped wire.  The green and black are power and ground and on most 510s there is a corresponding connector usually taped to the harness with a green tape.  You will need to create a harness to connect the ends of the white wire to the coil and distributor as described in the write-up.   No, the white wire(s) do not connect to anything on the tach or inside the car.  They MUST be extended to the coil and distributor as described.   The loop creates the "induction" signal that drives the tach.