Someone just informed me that the 55/56 temperature sending unit is larger than the 57. The 55/56 is 3/8 NPT. I want to retain the 55 gauge and sending unit, but I will be using 57 "G" heads. It was suggested that the 57 sending unit bushing be drilled and tapped for the 55 sending unit. However, Concours sells the 3/8 NPT bushing. Is the OD of the 55/56 bushing the same as the 57? I would just as soon remove the 57 bushing and install the 55/56. 

Yes, they are the same O.D.

John - "The Hoosier Hurricane"

Thanks, John. If the 55/56 sender is 3/8 NPT, is the 57 sender 1/4 NPT? If that's the case, it would be easier (and cheaper) to use a 1/4 to 3/8 NPT adapter. 

IIRC, the business end of the early temp sender is bigger than the later sender opening. You seem to be very care and precise in your work. Pull the bushing using the tool Concourse sells, clean out any corrosion, and install the larger one. It’ll look better, probably read better, and you’ll be happier in the long run.

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

Thanks, Miker. I found the bushing puller on several sites. Is there any trick to installing the bushing? What sealer is recommended?

Just make sure the bung/bushing is going in straight.  I used a little RTV when I did mine,  but something like Permatex Aviation should work good.





54 Victoria 312;  48 Ford Conv 302, 56 Bird 312
Forever Ford
Midland Park, NJ

Is the bushing pressed in/tapped in? I have concerns about the possibility of damaging/cracking the head around the area of the bushing during removal/installation. Also, as I mentioned to Ted, I know that the original temperature gauge is not very accurate. Considering that AutoMeter includes adapters with their gauge, how detrimental will using an adapter be? By the way, I will be using AutoMeter gauges in addition to the original 55 gauges. The AutoMeter temp sending unit is installed in an upper radiator hose adapter, near the thermostat housing, where Ted says I'll get a better reading than from the location at the back of the head. 

The bushing is pressed into the head



Lawrenceville, GA

IIRC, because it’s been years, I screwed a brass nipple into the bushing and used it as a handle to line things up and then carefully tapped it in. I probably finished with a steel nipple. I don’t remember it being a problem, and I know I didn’t use a press.


miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

I did not us a press either.  Just tapped in it..  The head was still on the engine, which was in the car.


54 Victoria 312;  48 Ford Conv 302, 56 Bird 312
Forever Ford
Midland Park, NJ