Temp senders on my '51 8CM

[WABOOM]

I need to replace 1 or both of my temp senders on my 51 Mercury. There is the factory one to the original dash gauge, and there is a second one to an aftermarket gauge mounted under the dash. Neither work. The aftermarket one is on the drivers side of the engine. Does this look like a universal type? I don't understand how the wire connects and also can't find a replacement online for sale. Any help is appreciated.

First picture is aftermarket, second pic is factory.

 

[flathead 53]

I would replace both with a dual gage panel under the dash and two mechanical gages .you can buy them at auto zone about twenty dollars each . do not use teflon tape or pipe thread sealer on the fittings . I have done the same in my 53 f-100 the new gages are better then the stock gage and you can see temps from both sides . only my opinion.

 

[WABOOM]

That sounds good to me.

 

[flatford8]

The stock one is electric. The after market is a capillary tube. I agree, two after market ones under the dash would work well. You can add an oil pressure gauge too if you want....Mark

 

[WABOOM]

The stock one is electric. The after market is a capillary tube. I agree, two after market ones under the dash would work well. You can add an oil pressure gauge too if you want....Mark

Should I get 2 capillary tube set ups?

 

[JSeery]

The capillary ones would work fine, the electrical gauges are usually more expensive. On the original electrical gauges the sender is a ground for the gauge. If functions by opening and closing a set of points very rapidly, which regulates the current flow to ground. This current flow in turn provides a gauge reading. Modern sender units function as a variable resistance. On an electrical sender unit you must have a good ground to the engine, with the capillary sender there is no electric current involved and grounding is not an issue. The capillary sending unit will require an adapter because they are fairly large for the hole size and depth available.

 

[mfirth]

Capillary's on mine are GR8. m

 

[Merc Cruzer]

Gauges in my 53' Merc......bought mine at O'Reilly's...capillary's...no issues

 

[tubman]

I have the same setup you now have. The stock gauge is connected to the one-pole sensor and an auxiliary mechanical gauge is connected to the other side. My stock gauge has always worked fine, and I didn't like the idea of having a "dead" gauge in the cluster. I am very satisfied with this setup and he gauges track each other well. One of the things that surprised me is that the stock gauge seems to react to temperature changes faster than the auxiliary gauge.

 

[rotorwrench]

The old King Sealy system was a damn good set up. They lasted years with no troubles and I'm sure that there are quite a few that are still in service. A lot of folks find it odd that they read full HOT when the ignition switch is off but that's the way they were designed. The right side sender was the one that gave an actual temperature reading. The sender on the left side head is just a high temp on/off type switch. When the temp reaches the high temp set point it just indicates full hot on the gauge. Since the two sides are independent outside of the radiator, they needed to monitor both sides for over temp so this is what KS came up with. I've found quite a few good senders & gauges from parts cars and even some NOS KS parts on flea-pay.

I just can't stand add on gauges hanging down from the dash. Just a personal thing though.

 

[Merc Cruzer]

rotorwrench,

If you can explain how to re-collaborate the gauge I will gladly reinstall the original sending units and re-hook it up to the gauge in the dash. I played with it for over two years, to include buying two sets of sending units (not cheap) and a second dash gauge then gave up with the original set up. I do have to admit that I do like to see the difference in the temperatures for the two sides (+/- 5 degrees). I do have a laser temp gauge and have confirmed the temps on the gauges. It may not be pretty but it gives me peace of mind when driving.

 

[JSeery]

So what is the issue Merc, are the sensors you have not working? You would think with that many senders and a second gauge one of the combinations would have worked!

 

[Merc Cruzer]

Reading 3/4 of the gauge at normal running temp (180), would like to re-calibrate it to read the middle of the gauge at 180.

 

[Drbrown]

Related .... Have a '47 AB and understand from various forum postings and my own experience that the right side of the engine typically warms-up faster and runs a little hotter than the left. I suspect that the right and left sides would seldom show the same temp if one was using the same gauge on both .... never tried it. (My OE gauge uses only the right side and my after-market the left side)

 

[JSeery]

Reading 3/4 of the gauge at normal running temp (180), would like to re-calibrate it to read the middle of the gauge at 180.

I haven't looked inside the gauge, but would guess it would be a little touchy attempting to adjust the bimetal strip or gear linkage.

 

[Drbrown]

Merc Cruzer: I am about to email to another forum member my description (with photos) of how I recalibrated (adjusted is a better description) my OE fuel and oil pressure gauges. My OE temp gauge was okay at the time but the adjustment technic would be the same. Assuming your OE gauges are the same as mine, it requires disassembling the dash gauge cluster and removing the gauge face, working on a "live/hot" gauge and is a "delicate" procedure, but can be done.

You could also adjust your fuel and oil gauges if desired.

If you're interested, email me at gfdanbrown@yahoo.com and I will copy you with my procedure/photos.

 

[JSeery]

Merc Cruzer: I am about to email to another forum member my description (with photos) of how I recalibrated (adjusted is a better description) my OE fuel and oil pressure gauges. My OE temp gauge was okay at the time but the adjustment technic would be the same. It requires disassembling the dash gauge cluster and removing the gauge face, working on a "live/hot" gauge and is a "delicate" procedure, but can be done.

I would be interested as well. jseery@ymail.com

 

[Merc Cruzer]

I would be interested as well. jseery@ymail.com

Thanks for the offer. I sent you an e-mail. My oil gauge is good to go and I calibrated the fuel gauge by bending the float rod (after emptying the tank and then putting in the correct amount to have the tank to read half full. That was done after I ran out of gas, shortly after buying the car, and the gauge still said I had an 1/8th of a tank. If anything it shows empty and will still have a gallon in the tank.

 

[rotorwrench]

My old hand me down 1951 Mercury that my Pop traded for in 1954, never did indicate in the middle. The 1950 & 51 Mercury cars didn't have any temp amounts on the indicator. It just had a tick for cold, mid point, and hot. It always gave a reading between mid point and hot. All of our other 8BA powered vehicles were pretty much the same. You always knew when they got hot when that cloud of steam came out from under the hood. I never really worried about it much otherwise.

To calibrate one, it would have to be calibrated for Hot at the over heating point. Where it rides in between is anybody's guess.

 

[tubman]

My '51 also reads about 3/4 when it's at 180. I think that is the way they were originally set up. I would hesitate to try to change the gauge to work differently that it was originally designed.

Also, I have heard nothing but bad things about the reproduction temprature senders. If they work at all, it's only for a very short time. Better to try to find an NOS or good used original unit. I was able to repair a non-functional original unit by disassembling it and cleaning and filing the points. There is an adjustment screw inside the sending unit as well; if you want to try to adjust it, you sould begin there.