Interesting reading Leathermang...

I use the KB Hypereutectic Pistons in a number of engines with very tight bore clearances (.002") and ring gaps of .014" top and .016" second. Good quality products right out of the box, although I opt to have my skirts teflon coated before delievery.

One thing I have noticed is almost all liquid cooled engines will run at 150° to 160°F even without a thermostat. The interesting part is how fast the engines come up to that temperature.

On my 7.4 Litre Pontiac, the heater is 'warm' in less than 1 minute and the engine is up to 160° in less than 5 minutes.

On a 104° day here in California, sitting in the drive-through at In-N-Out for 25 minutes with the A/C on, the coolant temperature will never go past 185°F. That is with the stock 4 row copper/brass radiator, 60/40 water/coolant ratio and stock engine driven 7 blade fan.

At 104°F ambient temperature at 70mph with A/C on, coolant temperatures stay right at 165° to 170° and steady.

My theory has always been that with the 'hollowed out' thermostat body in place, functioning as a restrictor, the coolant flow would be identical to the flow available when the thermostat was fully open.

No I certainly agree with you about the 'cold oil' theory, but in reality, the oil heats up quick in an engine, must faster than the coolant seems to.

Much like 'piston slap' that we used to experience with Forged Aluminum Pistons and very loose clearances (.007") cold, would go away after about 30 seconds because the pistons heat so quickly.

Interesting...Bert