The Stovebolt Site Forums The Shop Area Engine Shop temp sending unit size

Bought a temp sending unit for my 1955 cameo 235 eng but the 3/4" ish thread size is too big it should be closer to 1/2" ish so think head may have been changed ? Question is what year did thread size change to smaller size ?

Later model engines with electric sending units. have a 1/2" tapered pipe thread for the temp sending unit, and there is an adapter available for the older engines with a 5/8" straitght thread and the capillary tube type of temp gauge. Is your gauge electric, or direct-reading?
Jerry

stock electric gauge

I deleted my last post as it contained incorrect info. As HRL said, it is a special bushing. My ‘52 with a ‘59 235 has a bushing. It looks to me like a 1/2” NPT to whatever the temperature probe is. Here is one from from Classic Parts that may work. It’s also possible that you have the wrong sending unit.

Here is a couple of pictures of mine, but keep in mind that mine is a direct reading gauge.

Can you tell us what sending unit you purchased?

What ever the sending unit threads are you will have to adapt it to what you have on your 235

We who use mechanical senders use and adapter that probably wont work for you. Its 1/2 pipe. To 5/8 18 UNF straight.


Later I converted my 50 to electrical sender and had to make my own adapter


Let us know what you have

bought the one from Classic Parts Part # : 53-811A ( with gauge ) which I know says 57 to 78 not 55 but was thinking would work . I don't see they list one for a 55 and down etc . they do list a 56 with different electrical end but they don't give thread sizes .

I looked at that sender on the classic parts web site, it looks very similar the the aftermarket sender I used on my 50. My aftermarket sender was 1/8 pipe


So in my case I had to go from 1/8 pipe to 5/8 18 unf . That was the size in my 54 235 head for mechanical sender. (This is just an example for my 50)



The question is what size provision is in your 235 head? If its 1/2 pipe then try a 1/8 pipe to 1/2 pipe reducer bushing from the hardware store.

Take your sender with you.
Again, You'll need to verify what size your sender is.

Don't rely on my example

All of the "stock" 55-2 trucks I have worked on had the capillary temperature gauges. 56 through 59 had the electrical gauge and sending unit. That doesn't solve your problem as you need the correct sender for what you currently have. It appears that you have a later head that uses the smaller sending unit. Possibly a 59 or later sender would match up.
Fred