Surplus Tach wiring help

[Barrman]

This is a tach off of a MV. I don't know what kind though. I want to put it on my 6 cylinder 24V Gasser. Does anybody have any ideas of how to make it this work or what it is from?

Thanks.

 

[badgmc56]

Looks to me that - signal terminal is hooked up to the negative side of the coil. Where did you find it? I have been looking for a 24 volt tach myself. My gasser has a reb- shift kit and a tach would be very helpful in shifting.

 

[Barrman]

I got it from Sermis.

So, you are thinking one wire hooked to each side of the coil?

 

[emmado22]

it's a Humvee tach... Look in the Humvee TM's.. Should be under special kits section.

 

[Barrman]

Great, thanks!

Umm, that means it is a V8 diesel tach and probably not going to work on my I6 Gasser. I will look it up and see if I can even hook it up. If I can get a reading, then I will worry about accuracy.

Lets see, a V8 sends 4 pulses per crankshaft revolution while a 6 sends 3 pulses per rev. Which will make the tach 25% slow, right? It will match the 12% slow speedo. I need to make up little placards like airplanes have next to the compass and air speed indicators showing the conversions to make them accurate. I will be so busy doing math in my head, I will never get bored while driving.

 

[aboonski]

I recently bought one just like Barrman has on Ebay - NOS. When you look at the wiring schematic for the Humvee, there are six (6) terminals on the Hummer tach vs. four (4) for the tach we have. Also, I have been told the Humvee tach has a black indicator needle where mine is red. The lamp wiring is separate from the screw terminals and is merely a red & black wire that attaches to the lamp itself. The person I bought the tach from indicated it might fit an LMTV dump truck? What is that? I think the wiring for this is quite simple requiring a pulse generator from a 6.2 Humvee motor; unfortunately if I install that in my CUCV I will not have a vacuum pump to shift my transmission. I know I posted pictures on other threads but wanted people to know that the person I bought mine from has others and is also a member of Steel Soldiers. His user name is aarron81. I was happy to have seen this thread because of the photo with the wiring sticker on the back. Mine was covered up with the mounting bracket - when I pulled that off, I got to see the wiring order for the first time.