The water pump....
Yecccchhhh:
Broken blade on impeller:
Oh and the shaft is worn clean and smooth. The press on ribs are worn down to nothing...
Tonight after about a 15 mile drive there was no variation off about 80-85C. Solid and smooth. Like I said, tomorrow I'll put it to a little better test.
I'm going to keep the Kirkham - it does keep the fill at the high point and looks cool.
I think I can toss my coke bottle catch can though. Tomorrow I'll put the 16# cap back on before I take it out (and keep the bottle, just to be sure).
The water pump had been mentioned in elmariachi's topic, about the impeller. I'd never considered it because (1) the car only had 500 miles on it when I got it, and it's misbehaved since then and (2) whoda thunk at 500 miles the water pump had been abused?
S**** said he'd only seen this twice in over 20 years...
My guess is this is the equivalent of a belly flop. Water in the pump, put it in second, and instantly rev it to 6000RPM and pop the clutch (on a very safe track). All that torque from the crank pulley couldn't move the water pump and the pump lost. Metal meets water, and water is harder (It's one of those f=ma deals) It popped the blade and stripped the press-on threads. Look at how every metal edge is polished. If the blade had actually broken loose the failure would have been immediate instead of latent.
Anyway, now it's off to Walt Hane for the final tune.
I would like to know the limits though.