flathead temp.

jan bogert

jan bogert

Senior Member
i've installed new thermostates in my '42. 180degrees. my left head reads 200 degrees at idel sitting for ten mins on the temp. guage. is that alright? i'm getting a guage today for the right head will post degrees of right latter. i do know that the right gets hot very fast compared to the left. just by feeling the water pipe. does the right side get hot faster? or do i have a bad thermostate? what is a good temp. for it to run at sitting ideling?:):)
 

At idle the temp will rise because the engine is not getting the water or air flow needed to dissipate the heat. Just like when you shut the engine off, the temp will rise before it cools down.
 
an idling flat head will reach around 190 to 200 degrees, theres a few things that will cause one side of the engine to run hoter, but i would pull the thermostst and see if the temp comes down, if so you found the problem, all thermostats do is hold the water in the engine till it reaches operating temp, be it 160 or 180, when those temps are reached the thermostst opens and will keep the water at the set temp, 180 is the desired temp, it burns the fuel better for best fuel milage, and helps stop plug fouling along with the right plug heat range
 
ford1 said:
...the thermostat opens and will keep the water at the set temp
Click to expand...
To be clear, the thermostat will keep the water at the set temp OR ABOVE. It regulates the minimum operating temperature, NOT the maximum.

Also, the outside air temperature will influence your operating temperature a lot. The loose rule of thumb seems to be operating temperature equals OAT + 100 degrees. Seems to be very close.
 
If one side heats a lot faster than the other, you may want to check for combustion to water leak- be it head gasket or other...
Karl
 
Although good air flow plays a significant part of cooling, what shape is your radiator in? Clean tubes and unbent fins will certainly help matters.
 
guys, i pulled the therm/st. and it opens and closes. i installed a right side temp. guage and thier about the same L/side 185 R/side190 at idle 10 min. is this good? i think so i did not take the car out on the street yet. then i think it should be right around 175/180.:):):)when moving. the above i'm wrong it was 20 min. at idel.
 
From my experiance, you are doing good. You may find you will want to remove the stats in warm weather. That allows more water flow. I also found about 100°F rise over air temp.
 
Sometimes you don't know where your parts are coming from and how good their quality control is. You might get a thermometer where you can heat up water on your stove top with the thermostats in the water to verify at what temp they are really operating.
 
A good way to check a thermostat is with a pan of water on the stove. first open the cold thermostat enough to slip a feeler gauge into the opening, then suspend the thermostat in the hot water by holding the end of the feeler gauge with a pair of pliers, when the water temp reaches the temp of the thermostat it will fall of into the water. you need a acurate thermometer for the water.
Also remember a 180* thermostat starts to open at 180* and is fully open at a higher temp. (195*)
 
I'm running 2 av8's, both with 3 blade fans and 180º stats and to me they run better up close to 200º than 175º, they never boil and 200º - 215º never bothers me, but this is me and some will cringe when reading this, you will be okay with the aluminum heads.


Vergil
 
There are two types of thermostats, when the cheaper, perfectly good, stats fail, they fail closed... When "reverse popet" thermostats fail, they fail open... I bought a couple of these at a Kragen, it took a bit of discussion to arrive at their terminology- they called them "heavy duty"
I like 180 degree, which is where my engine pretty much stays year round- can go as high as 190 on a real hot day, Norcal
Karl
 
You must log in or register to reply here.
Back
Top