hmmwv tachometer installation

[Retiredwarhorses]

Because the military tach is a 3500 rpm gauge which is more responsive to a low-rpm diesel engine. I am preparing to install a new HMMWV 3500 rpm tach in my M1028 in a custom-built cluster and have the HMMWV sending unit which mounts on the oil pump drive, however I have not tested this connection and do not know that the signal from the sending unit will be correct. I am also interested in knowing the outcome of this thread. Here is a photo of my sending unit and cluster -

View attachment 820184 View attachment 820185

1st, The tach you have pictured is simple, I have installed many and sell them, the instructions for install are available via search in this forum.
2nd, the OP is not installing this into a hmmwv from what I gathered, it a 12v civilian truck.
so instead of reinventing the wheel, just buy a civiy Tach already available The civilian H1’s all have Tachs.

The Tach drive you refer too in your pic is for the STE/ICE application, it was not meant to produce the correct signal for
TCM applications but does for this Tachometer only, the cannon plug version of late style Tach gets its signal from the
generato.

 

[Sharecropper]

1st, The tach you have pictured is simple, I have installed many and sell them, the instructions for install are available via search in this forum.
2nd, the OP is not installing this into a hmmwv from what I gathered, it a 12v civilian truck.
so instead of reinventing the wheel, just buy a civiy Tach already available The civilian H1’s all have Tachs.

The Tach drive you refer too in your pic is for the STE/ICE application, it was not meant to produce the correct signal for
TCM applications but does for this Tachometer only, the cannon plug version of late style Tach gets its signal from the
generato.

Warhorse - Thanks for your reply. I apologize, the thread is so long and old that did not read all the way back and see that the OP intended to install the tach in a civilian truck. Regarding my tach, do I understand you correctly that the sender that I have will indeed provide the correct signal for my tach? If not, is there a specific sender available that will provide the correct signal? Thanks again for your help.

 

[Retiredwarhorses]

The statement about the OP’s application vehicle is the post above my reply....

But yes, if you have the 4 screw Tach, that sending unit provides the correct signal.

 

[Sharecropper]

The statement about the OP’s application vehicle is the post above my reply....

But yes, if you have the 4 screw Tach, that sending unit provides the correct signal.

Thank you soooo much! Yes I have the 4-screw tach. Question - would you happen to have the male end of the cannon plug so I can fabricate the harness from the sender to the tach? Here's a couple photos of the female end at the sender -

 

[Valor]

why waste the time and money trying to make a military 24v Tach work in a civilian truck, there are many civilian Tach’s designed to work in your truck.

Good thought! I'll have to check on that. Thank you.

 

[Valor]

Thank you soooo much! Yes I have the 4-screw tach. Question - would you happen to have the male end of the cannon plug so I can fabricate the harness from the sender to the tach? Here's a couple photos of the female end at the sender -

View attachment 820187 View attachment 820188

I would need one too.

 

[Retiredwarhorses]

Thank you soooo much! Yes I have the 4-screw tach. Question - would you happen to have the male end of the cannon plug so I can fabricate the harness from the sender to the tach? Here's a couple photos of the female end at the sender -

View attachment 820187 View attachment 820188

just cut the plug off and use new connectors, makes no difference which wires you use for signal, works
either way. Or use Posi-taps.

 

[Sharecropper]

just cut the plug off and use new connectors, makes no difference which wires you use for signal, works
either way. Or use Posi-taps.

Thanks !!!

 

[Thumper580]

Can someone tell me the outside diameter of the 3500rpm M998 tachometer body, not the ring that goes around the face. Need the body OD for fitting into a housing. Thanks, guys.

 

[Sharecropper]

Can someone tell me the outside diameter of the 3500rpm M998 tachometer body, not the ring that goes around the face. Need the body OD for fitting into a housing. Thanks, guys.

Yeah let me get back to my shop and I’ll measure it for you.

 

[Sharecropper]

Can someone tell me the outside diameter of the 3500rpm M998 tachometer body, not the ring that goes around the face. Need the body OD for fitting into a housing. Thanks, guys.

The tach body will pass through a 3-3/8" hole. There will need to be a small notch at 6:00 for an indexing ridge on the tach to fit into. Hope this helps.

 

[Thumper580]

The tach body will pass through a 3-3/8" hole. There will need to be a small notch at 6:00 for an indexing ridge on the tach to fit into. Hope this helps.

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Perfect. Thank you.

 

[Crapgame]

The tach body will pass through a 3-3/8" hole. There will need to be a small notch at 6:00 for an indexing ridge on the tach to fit into. Hope this helps.

View attachment 820249

Is that a 24v Map Light out of a VW Typ 181 Thing or Typ 183 Iltis?

 

[Sharecropper]

Is that a 24v Map Light out of a VW Typ 181 Thing or Typ 183 Iltis?
View attachment 820340
View attachment 820341

I bought those lights a few years ago from a lady on EBay who stated that they were for a Pinzgauer.

 

[Agelai]

why waste the time and money trying to make a military 24v Tach work in a civilian truck, there are many civilian Tach’s designed to work in your truck.

which ones?

 

[TenTires]

Ok.... thread from the dead here, but a lot of good info so I'm going to keep it going.

I have an M1038, 3spd truck. I'd like to get a tach working in my truck like several others. I'm seeing a couple different NSN's and a hand full of different sensor #'s, hook up methodologies etc.

The two main NSN's I see are 6680-01-474-0384 and 6680-00-825-2076. What gauge/sensor combo will work for my application?