ERA temperature sender questions

[lippy]

Hey guys. I just received my new dual-plane Blue Thunder intake. Really nice piece, high-quality.

At any rate, my old Victor intake had a 1/2" NPT threaded hold for the temperature sender, and the new one has a 3/8" NPT. The sender that comes from ERA has an 1/2" NPT reducer that fit into the old intake, and the sender itself is threaded with some sort of smaller thread that fits inside the reducer. The smaller thread sort of looks like 3/8" NPT, but it isn't. It's slightly smaller, and I can't tell what it is.

So my choices are: (1) Get a 1/2" female to 3/8" male NPT reducer, which is bulky and ugly, (2) Figure out what the smaller thread on my sender is, and try to find an adapter, or (3) Try a new 3/8" NPT sender, which most seem to be.

So my questions are:
- Does anyone know what the smaller thread on the sender *could* be, if it's not 3/8" NPT and not AN? It's slightly smaller than 3/8" NPT.
- The sender is soldered on to a thicker wire. Can I replace it with a more standard 3/8" sender, and just use a spade connector on the wire I have? Or does it work differently?

[1795]

I had to get a new sending unit for my MGBrace car and it came with an odd sized thread. I ended up taking the thing to the hardware store and auto parts store and trying out various sized threaded fittings until I found one that fit. It took a while, but worked. Do you have one of those thread sizing gauges?

[patrickt]

Originally Posted by lippy

Hey - Does anyone know what the smaller thread on the sender *could* be, if it's not 3/8" NPT and not AN? It's slightly smaller than 3/8" NPT.

I would guess 1/4" NPT. But if you stop off at a plumbing store tomorrow the guy at the counter will tell you for sure.

[lippy]

1/4" NPT makes a ton of sense but I don't think that's it. The OD of the smaller thread on the sender itself measures 0.619". 1/4 NPT = 0.540", and 3/8 NPT = 0.657". So what could it be?

SAE inverted flare?

Edit: Actually, I think it's just 5/8-18. Summit has sender adapters for mechanical senders in this size.

[DanEC]

I went through this and did my usual squirrel running around in the middle of the street thing until I finally called Doug (last entry in thread).

Where to put water temp sensor?

I can't tell if you are dealing with something slightly different or not.

Dan

Edit - meant to add that Doug said 3/8" NPT tap

[patrickt]

NPT, NPTF, etc., threads per inch, pitch diameter... I never get it right. I don't even try hard anymore. I take the piece to the local plumbing store (not the hardware store) and ask the guy "can you tell me what these threads are?" They have high quality, true gauges and get it right every time. And they usually enjoy doing it for you, too. Try it, you'll like it.

[CJ428CJ]

Lippy - If you have a mechanical gauge, I don't think you can replace the sending unit. The sending unit and tube to the gauge are filled with some kind of liquid or gas that expands and contracts with the temperature. If you have an electrical gauge, you might be able to replace the sending unit with a different size.

[lippy]

I got the part. Inside is 5/8-18. Outside is 3/8 NPT. It works. Summit has these adapters.

[patrickt]

Originally Posted by lippy

I got the part. Inside is 5/8-18. Outside is 3/8 NPT. It works. Summit has these adapters.

... and why a 3/8" NPT has threads that are really .675" is anybody's guess.

[kevins2]

Originally Posted by patrickt

... and why a 3/8" NPT has threads that are really .675" is anybody's guess.

For the same reason legal documents are so unnecessarily complicated - job security for those in the business

[patrickt]

Originally Posted by kevins2

For the same reason legal documents are so unnecessarily complicated - job security for those in the business

Here's my complaint: If you're going to use a number to describe a part, and the number has nothing to do with the size of the part, then don't pick a number that sounds like it does. Instead, pick a number that clearly has nothing to do with the size. Wouldn't it make more sense if Lippy was able to say to the parts counter guy "the 1873985 thread fitting was just a hair too big," and then the parts guy would reply "ok, then the next smaller fitting is the 8142874 thread fitting." Don't get me started.

[strictlypersonl]

Just for reference, NPT sizes refer to the ID of the fitting and/or tube.