additional gauges

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Joined
Apr 8, 2015
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Location
Upstate NY
My Car
71 Mach 1, 351c 4v, C6 trans, grabber blue with white interior
I'm thinking at some point I would like to add additional gauges to my 71 namely, oil pressure and water temp (thinking both electrical). Never added gauges so have some initial basic questions. I'm assuming I would need new sending units for the new gauges.

Can I add these additional gauges and still keep the original working gauges? 

Can I use some kind of NPT tee for the oil pressure so that I can use both sending units for old and new gauge?

Is there any other threaded spot for the additional water temp sensor?

Would one of those hose adapters ( the heater hose for example ) work for the sensor? Is water constantly flowing thru the heater even when its off?

Or, is it easier to just remove the current water temp and oil pressure sending units and replace with new gauge sending units?

Thanks for any suggestions!

 
Yes, you can tee off the oil pressure to keep both the light and the gauge. Brass T-block fittings are more compact.

If you have a 351C there's another threaded port on the water pump that can be used. I would connect the warning light switch to it and the gauge sending unit to the hole where the existing temp switch is. The heater hose on non-air-conditioned cars flows water all the time, but it wouldn't be very accurate.

The easiest? Don't keep the lights functional and use the existing wiring for the warning lights to feed the new gauges.

I would also add a volt meter.

 
Read my posts in the Aesthetics, Interior, Exterior section.

You will see what I did. If you can get a set of factory gauges, the old Amp gauge can be changed to volts by Bob at Rocketman's Classic Cougar.

Good luck,

Geoff.

 
Yes, you can tee off the oil pressure to keep both the light and the gauge. Brass T-block fittings are more compact.

If you have a 351C there's another threaded port on the water pump that can be used. I would connect the warning light switch to it and the gauge sending unit to the hole where the existing temp switch is. The heater hose on non-air-conditioned cars flows water all the time, but it wouldn't be very accurate.

The easiest? Don't keep the lights functional and use the existing wiring for the warning lights to feed the new gauges.

I would also add a volt meter.
Don, this is exactly what I'm doing, but with mechanical gauges and I am keeping the idiot light for now in my upgraded Rocketman tach conversion. Spent a lot of money on it, so I want to keep it with lights for now anyways.

Geoff.

 
Thanks for the info guys!

Would someone happen to have a pic of the other NPT port on the water pump for the 351c?

I see the one where the current sender unit is screwed in but I'm not seeing an additional one?

Thanks!

 
The other NPT port is on the passenger side of the water pump, below the upper front heater hose, below and in front of the temperature switch, and kind of hidden behind the alternator.

 
Thanks for the info guys!

Would someone happen to have a pic of the other NPT port on the water pump for the 351c?

I see the one where the current sender unit is screwed in but I'm not seeing an additional one?

Thanks!
All my original center gauges are working, but I wanted something more precise and reliable to control the engine. To keep the original look inside and modify the least possible the car I did the following:

For the Amp meter I did the amp to volts conversion from the rocket man. It works great and have more usuful info than amps.  

For the water gauge I added a sending in the NPT port that Don indicates and for the oil pressure sending unit you can use the T-block.

The extra gauges for the water and oil pressure are hidden behind a “mach 1” plaque in front of my shifter. Usually cars have a clock in this place, but mine has this plaque than can be easily removed. While I am driving I remove the plaque and when I go to meets or shows I put it back. 

Here is a picture of the location of the two sending units for teh water temp:




 




This Is a picture of where i hid the extra gagues. 





 
Very nice looking and good idea to keep things looking original!

The issue I have is that where your second sender is located, I have the distributor vacuum control valve.

What type tee did you use for the oil pressure? Any pics?

My oil pressure sending unit is also the big canister style for the oil pressure gauge.

Is there a tool to remove this or will an open end wrench fit in there to remove it? 

I've seen oil pressure sending unit tools for the smaller oil light sending units but was wondering about the bigger one.

thanks!

 
Last edited by a moderator:
Yes, just use an open end wrench on the oil pressure sending unit. Make sure use oil resistant thread sealer on all the fitting connections. I like Permatex Pipe Joint Compound on this type of fittings.

Here is how I did my switch and sending unit:



 
Very nice looking and good idea to keep things looking original!

The issue I have is that where your second sender is located, I have the distributor vacuum control valve.

What type tee did you use for the oil pressure? Any pics?

My oil pressure sending unit is also the big canister style for the oil pressure gauge.

Is there a tool to remove this or will an open end wrench fit in there to remove it? 

I've seen oil pressure sending unit tools for the smaller oil light sending units but was wondering about the bigger one.

thanks!
You can use an open wrench. the space is tight so you can modify a cheap open end wrench. 



 
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