Hey guys, came across a vintage Mack truck tachometer and was really wanting to put it in my 91 Dodge 12 valve. Really have no idea how to hook it up though there aren’t any wires hanging off. Any advice?

 

It's cable driven, it needs a cable driven from the engine to function. The b series did have a provision that was installed in oil fill location used in the dodge trucks. I would bet the parts are still available but I remember them being very very expensive.

 

I was able to get some images of the tach drive from Cummins but they were not sure where I could get the parts, it drives off the injection pump drive gear nut.
Jim

 

Found this:


The Mechanical Tach drive mounts on the timing case cover and connects with the Injection Pump Shaft for drive power. From the Cummins Parts Catalog you need;
1 Coupling, Tach Drive 3905306
1 Seal, Rectangular Ring 3903475
1 Adapter, Tach Drive 3903476
1 Drive, Right Angle Tach 3905217
2 Retainer, Tach Drive 3903644
2 Screw, Hex Head Cap 3027685
1 Seal, O Ring 3905218

In the Cummins Parts Catalog, it appears that;
Drive, Tachometer 3905309 is a kit with all of the above parts. But that is not spelled out clearly

Also, it does not state if the drive adapter is a 1:1 ratio or ? You need to check with your Cummins Parts Counter on the Ratio.


here: https://www.dieseltruckresource.com/...-drive-247108/

Hey, that's us ...Mark

 

I used to drive a Mack tow truck back in the 70's, powered by a twin turbo 903 Cummins, that truck could pull transit coaches just idling.

The mechanical tach pointer would bounce in tune with the clap of the rain caps.
Loved it.

 

I’ve read some articles about people converting mechanical tachs to electronic. Think that would work on this one? Might sound like a dumb question just a young kid trying to gain some knowledge

 

I am sure that you googled it:

https://www.google.com.mx/search?q=t...hrome&ie=UTF-8

, but it seems that any tach can be converted. Post up your result, as I am sure that there are others interested in this. Since I was never a young kid and was born with all my current knowledge, I can't relate .The only stupid questions are mine ...Mark

 

The tach drive parts from Cummins are available to the tune of about $350. The assembly is NLA but the individual pieces are still available.

 

On the cummins parts website or a different website?

 

From my local Cummins dealer.