With that out of the way, let's talk radiator, shall we? The weather and my mind are both in better condition so I finally got to swap out my leaky Spectra unit for the Black Horse Racing all aluminum one. You may recall from the Radiator thread that my A Body hoses should fit perfectly, and they almost do- the upper is loose by a 1/16" and the lower seems to fit just slightly tighter. The transmission lines threaded in and seal just fine, and the whole thing sits perfectly in the factory rubber isolators, which I didn't even touch. I did use compressed air to blow out every orifice before setting it in place, and nothing came out: no shavings, no junk, nothing.
Now for the overflow nipple mod. The nipple has tapered threads that begin at 0.290", getting larger of course (5/16 - 18). You're not going to find another nipple that matches that and accepts 3/8" hose. I mean, YOU might, but I couldn't.
I'd considered just using a 5/16" hose or drilling the threaded hole and retapping for a larger fitting, but neither of those made me happy. I would have loved to drill it out but the kid that originally did it got it off center and closer to the cap so the fitting would hit if I did. I also considered pressing a larger nipple onto this one but don't have the proper tooling for a good fit: I'd crush them trying as I couldn't achieve tolerance. I Could drill the brass fitting to an I.D. of 0.3125 and press fit the aluminum one inside, but my closest bit is "N" (0.301"), making the press fit a difference of 0.0124, or 12 thousandths. Normally 1 or 2 is enough...
After careful measurements and a bit of math I discovered that I could simply cut two fittings and thread them together, and I chose the Dorman above since it's compact and takes a smaller wrench than others. The 5/16" aluminum barb has 5/16 - 18 threads into the radiator, and I chose to go with -24 for this side of it. A vice and H.F. tap/ die set got us in business. The O.D. actually measured at 0.3125, which is necessary if you want 5/16 - 24 threads to catch on anything, but the flared end was removed with a band saw.
This left me with a brass 3/8 fitting that needed an ID of 0.272 to be threaded for 5/16- 24, and it measures 0.273. Perfect! I held it in a vice by the flats and tapped it after cutting the threaded end off. Once the 3/8 brass fitting is tapped then the walls outside the threads will be 1/32" thick, the same as brake line. If you do this be careful and get that tap straight! Also, there's no sense in creating more threads than necessary.
Now I could thread them together using Dap Tank Bond as sealant because it was $1.25, and I added an o-ring just to make it pretty. (The die can't get threads all the way to the base so the two had a slight gap.) I also removed the brass flats by sanding it round so I won't be tempted to accidentally unscrew these two.
The drain petcock is a plug type so I wanted the usual kind but for nearly $20 ended up with this instead:
Remove the plug from the adapter in the rad and it fits in its place.
A bit of 1/4" NiCopp gets you this, and it just clears the sway bar:
But I made it stick out too far and it hits the frame. I'll need to shorten it if I want a downspout so it's currently naked, and the valve sits flat up against the core support if turned that direction, but goes either way:
And a final view:
Upcoming mods include custom preformed heater hoses that are nearly finished.
