Hey B&D,
220F might b a little high for a non pressurised system with minimal glycol to push up the boiling point... even at sea level... 195 to 200 would b a little safer I reckon... I have played the temperature games on my listeroid and found that there is a definite sweet spot to operating at slightly above pure water boiling point.. to get there, I pushed up the glycol content but found a small problem with hydronic cooling due to viscosity.. Until the coolant gets a little warmer than 40 or 50 C, it does not cycle very well and caused localised hot spotting and boiling in the head channels.. spectacular to say the least... let it warm up slowly under minimal load and things work very well, but it is not foolproof... me being the fool... I also played thermostat games and managed to get it tuned up quite well too.. but, for me, this was again not to my wanting as I have no over temp shutdown when things go awry if the thermostat decides to fail closed... I am considering a very simple auto-top-up type of arrangement for the system, as should I have a catastrophic leak/pipe failure, similar things could happen... I like simple, easy and lazy... I am considering a small and open header tank with a float valve that gets topped up from our water mains system, this will T feed into the cylinder head top pipe, should any pipe break in the system, besides the safety feed of course, cool water will flood the engine, make a hell of a puddle and attract attention.... hopefully! No damage through overheat happens, it simply over cools and life goes on...
Agreed regarding pumps etc pushing better than they suck, but that is in a closed system... at best you can only get 1 ATM worth of suck on something, then you get a vacuum... but, from the little bit of practical I have had over the years, I have just found, personally, that radiators are a damn side easier to cool using a plain unducted fan sucking air through, than making up many hours worth of ducting to get the same efficiency by using a push air system...a further benefit, for me anyway, with the roid, is because of the relatively exposed and plain radiator without shrouds and ducts to shield the core, even with the small amount of windage and breeze through and around the radiator, from flywheels and atmospherics, should the main fan fail, unless under close to maximum load, the cooling is sufficient on the average day to keep the boil and seize demons at bay...Bonus!
A properly designed and fully ducted and sealed, fan pressurised system would definitely out perform a fan evacuated system in cooling capability... but that is not what I am talking about... What I am talking about is a minimalistic, fan/radiator pair, no frills, fancies, ducts or other....a suck definitely beats a blow in my books!
Agreed to regarding some form of thermal switching to hold the cold demons back in their stall until they are required... This is particularly evident and witnessed on this Beastie of mine.... pointless for me to cool the coolant colder than the hot water its supposed to be heating(coolant heatex in system)....
Keep it cooking...
Cheers
Ed