Technical 12V Tach on 6V System

I picked up a 12volt electric 4 cyl tach for my model a banger build. I'm running the original 6v positive ground. How do I need to wire this tach up for it to work?
Thanks

 

do you have the wiring info for the tach, for a normal 12v - ground application?

 

No I don't have any wiring diagram for it. I guess my question is more on: since the tach is designed to work on 12v system, must I add a component or wire differently for the tach to work accurately?


Drive fast & take chances

 

then I guess the first step is for you to tell us what kind of tach it is, and how many wires it has, what color they are, etc. With pictures. Figuring out the "normal" wiring for a mystery tach can be a challenge in itself.

 

I did the same thing, 12 volt cheapy jap tach and a step up transformer on my 6 v positive ground plymouth. It worked but was jumpy at rpm's so much so it was basically useless, I figured it was the cheapy 12v tach and a 6 volt points issue and disconnected it.
basically, my post is useless to ya as I answered naught.

 

On the jumpy thing, my son put a modern tach on his old Volvo with points, it was jumpy as soon as it revved up a bit. I built a tach filter with some capacitors and resistors from Radio Shack, it fixed the problem. so don't give up quite yet.

Problems with SW Tach - needle shakes

 

Ok thanks. I'll take a pic and post this evening.

 

Years ago, before cars had electronic ignition, I ran tachs , as did countless others, and had no erratic needle movement at all.
As Squirrel mentions, the problem isn't necessarily point style distributor.

Ray