Temperature
- Thread starter 46ford
- Start date
Fibber Mcgee
Well-known member
I'd think lower than that. No thermostats hasn't ever helped keep engine cool in my experience.
Fibber Mcgee
Well-known member
Old Henry mine run about that when 95 outside if his is 195 at 50 wont it be over 200 at 95? You probably have alot more experience than me, I am just going by what mine run. What is to hot for a flathead?
Old Henry
Well-known member
Too hot is the temperature that the water boils out of the cooling system. Any temperature up to that point doesn't hurt the engine.
At sea level without a pressure cap on the radiator that temperature is 212 deg. With a 4 lb. stock radiator cap, that raises the boiling temperature to 225 deg. So, anything above that would likely be "too hot" for a flathead at sea level, meaning that the water presssure would likely overcome the radiator cap pressure and boil out.
That boiling temperature decreases with altitude. So, at the elevation that I live at, 4,800 feet, the air pressure is only 12 psi. Adding my 4 lb. radiator cap, my water should boil out at 219 deg.
At the highest paved road in my state (Utah) - Bald Mountain pass - 10,715 feet, the air pressure is 10 psi. Adding my 4 lb. cap lets my water boil out at 210 deg.
At the top of Pike's Peak, 14,114 feet, the air presssure is only 8 psi. Adding the 4 lb. radiator cap will only keep the water in the radiator up to 202 degrees.
So, at the elevations that most of us live at we should consider too hot for a flathead to be above 220-225 deg. That being the case, I think we all have a much greater margin than what we think we do between what we think is too hot and what is really too hot. My temperature gauge is only 210 deg at the right side of the hot mark - still 10 deg. to spare at my elevation, 15 deg. at yours. So, when the gauge looks too hot, I'm really not; unless, of course, I'm on the top of Pike's Peak or maybe even Bald Mountain Pass. But, those elevations usually include pretty cool air so overheating usually isn't a problem.
Hope that helps.
My calculations made from data on this chart: http://www.engineeringtoolbox.com/boiling-point-water-d_926.html
And this one: http://www.engineeringtoolbox.com/air-altitude-pressure-d_462.html
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Old Henry
Well-known member
I'm not sure what "50" you're talking about. The only 50 46ford talked about was the speed he was going. His air temperature was 92. I don't think another 3 degrees air temperature is going to increase his engine temperature by 5-10 degrees.
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Old Henry
Well-known member
I agree. I've tried with and without stats and seen no difference on the top end. Of course, without stats the engine doesn't get up to operating temperature as soon and doesn't stay at operating temperature when going fast down a long steep decline (hill).
Fibber Mcgee
Well-known member
I take back everything I said(except for the stats) I don't know where I got 50 from either(maybe wishful thinking). If it was 195 at 50 degrees I'd be concerned but since I'm an idiot and don't pay attention to what I'm reading your fine(now I need to go find out what's wrong with me).
46ford
Senior Member
Thanks, I wondered about that. I have the standard equipment gauge and an additional mechanical gauge.
I did notice that the hotter the motor runs, the lower the oil pressure. I'm planning to get my spare radiator gone through, and also going to install a Melling pump on this thing. Also going to look into a pair of Skip's pumps.
