That's why I said "experientially".
Did it all.
Got over 500K on the 50 Tudor, about 500K on the Willys with the Merc.
I've tried 5-row cores, 14 pound caps (bypassed heater and prepared to replace water pumps), but taking off every other vane on the impeller plus keeping a restrictor in the upper was the ticket.
You know, you read about these things, talk to old flattie racers, and just squirrel it away...and when you have a problem, try one of those "fixes".
I also run 160's in summer, but some of these same *morons* claim you need to be running a 195 as you will never overheat.
With a 160, you can watch the temperature, modify your load to hold it.
With a 195, you think you're doing fine until the needle moves, and by then it's too late, as 212 + 4 or 7 PSI is knockin' at the door.
With a 160, holding 100MPH on the clock climbing the Grapevine out of Bakersfield, in July or August, went right past the water stop and crested at Gorman (or Ft Tejon) with the temperature at about 190 in the top tank (had one of them thermometers from my tool box and checked).
I tried climbing out of Lankershim and as I crossed Sepulveda on the way up just to Castaic many moons before (and before trying these things), it pegged and blew all the water out.
TR3driver said:
TOC said:
At speed, those two pumps spinning can move so much water that it cannot get down the tubes fast enough (and even if it does, it is moving so fast it does not have a chance to transfer heat to the fins properly) that you will (WILL) lift the factory 4 pound cap and pump all your coolant out the overflow.
I've never bought into the "moving too fast to cool" theory; but you are very close to what I feel is the real explanation : the radiator itself presents a restriction to flow, so at some flow rate the pressure drop across the radiator exceeds the cap pressure, and water starts to dump out the overflow BEFORE the engine overheats.
This is why most cars are configured with the pressure cap on the suction side of the radiator.
A related problem with too much flow is that the pump inlet is now below atmospheric pressure, which can suck the lower hose closed. Not too common on Triumphs with those short hoses, but on my Olds 88, the correct lower hose actually had a spring inside to keep it from collapsing.