Heater Core Fitting Size

I wrote an article on this that was published in some of the Recent POCA Newsletters. The "Console Valve Elimination" is in the Feb newsletter, electronically available here....

Heater Valve Elimination

Here's my instructions for matching up the valve body...

Build Your Heater Valve Eliminator Tube:

1. Take your heater valve to Ace Hardware
2. Buy a nipple fixture that will mate to the proper sized flare nut (3/8” Pipe), and also to ½” copper plumbing tubing.



There's also some pix of my design sprinkled in my #5357 Topic....

See Page 10/11 about 1/2 way down...

Rocky

My car is a 74. When I removed my valve and replaced with an electronic version I discovered that the thread on the original valve was 3/8"BPPT, British Parallel Pipe Thread. It is not a standard 3/8" pipe thread. The difference is the TPI, standard 18TPI compared to British 19TPI and the fact that it is a parallel thread not tapered. As I recall the flare is 45deg. I searched for the proper adapter but did not find the correct combination and ended up machining one. You may choose to cut off the flare and swap the flare nut for a standard version and re-flare. That would make the process easier if you plan on changing the valve with something different.

Steve

Thanks. I did some looking around and found some BSP (also called BPPT) fittings that would work, but they all have a 30* concave end. I attached a drawing of one. I can't figure out how to post a 2nd picture to this, so I will make another post with a picture of my heater core valve. You can see it has a convex taper, but apears to have an insert in the end of the fitting. Oh course its stuck in there. I have it soaking now, hopefully I can get it loose, and maybe it fits in the end of another fitting?
Phil

My old heater core valve

You are correct that the flare fitting is a separate piece. As I recall the top of the valve body is flat and the flare fitting seals with a aluminum or maybe lead washer.

Picture from ebay:

Steve

Your valve is the early style. Here is the later style that was on my car.

Picture from ebay:

Steve

Here is a picture I just found that give a view of the top of the original valve next to the fitting I made.

Steve

The tops of both valves are removable for rebuilding. Inside is a tiny water seal for the moving rod that is available -I think McMasters-Carr and a few other specialty shops still carry it.

I have the late valve. It was so stiff that it could not be moved with the dash lever. I could not see how to take it apart, but a little spritz with WD-40 immediately freed it up and she's worked like a champ for years now, leak free.
For your old style valve, maybe a fix like this:
http://pantera.infopop.cc/eve/...274/m/6391075316/p/1