Water temp gauge in 273

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Jake lagrange

Jake lagrange

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Hello I have a 69'dart with the 273 in I bought some gauges and the only one I haven't hooked up yet is the water temp gauge, I've heard there is a bolt on the side of the block you can poke it in I've heard there's adapters for the thermostat just looking for any advice any of you guys have
 
My 273 has the temperature gauge in the intake manifold. I don't know about the block
 
if youre talking mech. sender, that's news to me. As far as I know, there is no place to put a mech. thermocouple on a mopar. The bulb on a mech. temp gauge is quite large. Mopar SB's normally have a small NPT hole in the front of the intake manifold, that can only accept an electric sender. Maybe you could make something big enough to accept the mech. sender, but it would still have to neck down to fit in the small stock hole, where it would be rather divorced from the flow of coolant, thus of questionable accuracy. In the past, aftermarket has always been made for Chevy, possibly Furd. If it fits Mopar, it's purely by accident.
 
Well, you could try the water drain plug holes, about midway down the side on either side of the block. Same size thread as a radiator drain tap.
 
I used a number of fittings to use a mechanical sending unit. It is pretty big!!

The gauge seems to be pretty close to the right temp. I run a 180* thermostat and the mechanical gauge reads 180* normally. It starts increasing in bad traffic and after shutting off the engine, but goes right back to 180 when I start it again. I kept the factory electric sending unit you see in yellow (which reminds me I really need to redo it with some heat shrink!)

Temp Sender.jpg
 
I am just trying to think outside the box, but couldn't you drill out (make larger) and tap the existing temp sensor hole in the intake. NPT taps are available.
 
first of all it will require a pretty large hole to be tapped, which would probably take out most, if not all, of the existing casting boss, so the casting wall is only like a 1/4" thick to tap. Second, the bulb on the end of the tube is like a couple of inches long, I think the water jacket there is probably only an inch deep.
 
Jake lagrange said:
Is that on the intake? Where do you get the fittings?
Click to expand...

Just got back on FABO...long work days lately!!

I think I got all the fitting at Home Depot or Lowes. The fitting that came on the gauge sender is not NPT (can't remember what is ) so I had to get a fitting from it to NPT. From there it was all NPT. No leaks. It looks a little gnarly up close, but when you stand back it really doesn't stick out. And the fuel pressure regulator is close by.
 
Just put elec in. If it was me I wouldn't be tapping any holes to run a copper capillary tube 8 ft long. Copper breaks and then what? Another gauge.
Elec sender fails? Wire breaks? 5 minutes and $10 to fix.
Autometer has them, thats what I installed.
 
Here's how I've done it for years, we just did one on the kid's car...

The bushing in the gauge kit is 3/8" pipe, you have to find the proper one... Then you drill a 37/64" or 9/16" hole in the water jacket of the intake on the driver's side of the intake manifold next to the thermostat... Then tap it for 3/8" pipe thread....

Be careful when tapping the pipe tap so you don't go too deep... Make a few threads, then try the bushing... Then try a few more threads, and then try the bushing... Repeat until you can get to just thread like shown below. You just want to be able to get the bushing in and not bottom out the threads on it as then the sensor may bottom out on the water jacket...


Drill Size for Pipe Taps

Pipe Threads Frentz.jpg


Here it is from a top view...

DSC04044 b.jpg


Here it is more from a side view... Notice how many threads I have left above the hole, but the bushing is tight and will not leak... This is what you want to shoot for when doing it this way...

DSC04047 b.jpg
 
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rustycowll69 said:
I congratulate you. I didn't think it was possible. the brass fitting is a bushing but it's 3/8 male x 3/8 female?
Click to expand...

65Val said:
Nice work!!!
Click to expand...

Thanks... I've done this a few times over the years...

Like I stated before, you have to be very careful not to tap too deep with the tapered pipe tap... Depth is critical... Tap just deep enough to get the threads on the tip of the bushing to engage, then it will be good and snug and you will have some threads above the intake to help from bottoming out the sensor...

If you tap too deep, then you would need to go one step bigger on the hole and then get a 1/2" to 3/8" reducing bushing... Then there is another connection that may become a possible leak path in the future... I like to keep it as simple as possible....

Plus I like to read the temperature as close to the thermostat as possible so I know what it is seeing...
 
rustycowll69 said:
I congratulate you. I didn't think it was possible. the brass fitting is a bushing but it's 3/8 male x 3/8 female?
Click to expand...

I believe that it's 3/8" male with a flare thread for the female....

That's why I didn't use teflon tape on it - you don't need to use teflon tape with a flare thread as it seals on the flare, not the thread.... Teflon tape may disturb the sealing surface of the mating flares...
 
rustycowll69 said:
is the bushing readily available? or did it come with the gauge?
Click to expand...

It comes with the gauge, but I've seen them sold separately at Mancini Racing... I can't find a link to it on their web site, but I know that I've seen them in their showroom in the past when I was there... It's the bushing for the temp gauge, you would have to call them and talk to them so they can figure out what it is...

I haven't seen anything like it in a hardware/home improvement store... It has a special landing on the inside where the sensor bulb seats/locates that you don't have on the generic hardware store bushings....
 
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