***Update on Temperature Gauge***
So I ordered a couple of Stewart Warner gauges and a two hole under-dash panel bracket...an Ammeter, as my original hasn't worked since I bought the Burb, and a mechanical Temperature gauge to help analyze what my original gauge is telling me. I did a little research and found that these mechanical gauges will accurately measure the temperature of any liquid, so I plan on using this one to monitor my A/T fluid after I sort out things with my water temperature.
I utilized a plugged 1/2" NPT hole on the drivers side head of my 454 so that I could still keep the electric sending unit operating...which makes comparing the two gauges much easier. As this tapped hole is located a little above the exhaust manifold, I used a couple feet of 1/4" ID X 1/2" OD rubber hose to insulate and protect the capillary tube (all the way past the firewall and into the cab), as well as some thin metal tape (crumpled up for a better insulation factor) from the Sender Bulb out past the manifold a ways (as a heat shield).
After refilling and "burping" the coolant to the best of my ability, I went out for a 45 minutes drive in our local hills of Palos Verdes. Not much of a test compared to the "Grapevine", but I mainly wanted to get any air pockets filled in with coolant, check for leaks and compare "around town" readings. At the halfway point of the drive, I stopped and found that the radiator had sucked coolant in from the recovery tank (it was at the "Full Hot" line when I left, and was now at the "Add" line) so I topped off the recovery tank and headed for home. Once home, I checked the recovery tank again, and as it was still at the "Full Hot" line, I believe all air pockets should be gone.
Results:
Spoiler alert...the two gauges did not read anything close to what I had expected, but I didn't take any pictures until I got home! While driving, the S/W gauge read between 200 and 210 almost the entire drive (after initial warm-up of course), but when I pulled into my driveway and sat with the motor running, it stabilized at what looked like 212 degrees. While driving, the factory gauge had been holding steady just about on top of the first mark past "C" (well technically, it's the second mark past "C"), but in my driveway with the motor running, it rose to about halfway between that first mark and straight up. I then decided to shut the motor off (with the key in the "ON" position) and see how much the temperature would rise without any circulation/fan. The S/W topped out at just above 230, and the factory gauge made it to just above straight up.
Now I do realize that there are "control issues" with the testing methods in place here...brand new mechanical gauge verses a 48 year old electric gauge (with a new American Autowire sending unit)...and...mechanical sender bulb installed in the water passage of the head verses electric sending unit installed in the water passage of the intake (right next to the T-Stat)...but I was expecting/hoping for something that I could say "well, that makes sense"...but I'm still puzzled! I guess I need to return to the "Grapevine" so I can compare what the S/W gauge reads when the factory gauge reads past the "H". Once again...I'll report my new findings!
Woody
