Mechanical temp gauge False overheating

[Medic0893]

I recently replaced my worn out TBI motor with crate carbureted motor. The new engine sat for a while waiting for the old girl to take a dump. She did and the new one is in. Initially I had all kinds of overheating issues. Tried a bunch of things to no avail. Turns out the water pump fins deteriorated and it wasn’t moving water. I replaced the water pump and all is right with the world. Just a thought.

 

[GoToGuy]

New engine with old water pump. Recipe for disaster.

 

[GoToGuy]

I'm not surprised as the engine starts and warms up there are areas that heat up at a faster rate then others. Is it too hot? Yes and no. As the pump circulates the coolant it intermixed
with remaining block coolant until it warms enough to open the thermostat. Then modulates the temp to main desired thermostat setting.
Temp instrument gauge inoperative? Or deleted as never installed?
Coolant system tight no leaks. Radiator cap good condition, fits properly, using 15 psi cap? If so a 15 lb cap raises the boiling point of water to approximately 260° F. 50/50 coolant water mix adds more to that number.

 

[Schurkey]

Radiator cap good condition, fits properly, using 15 psi cap? If so a 15 lb cap raises the boiling point of water to approximately 260° F. 50/50 coolant water mix adds more to that number.

15 psi WITH a 50/50 mix is good to 265 F.

15 psi without anti-freeze/anti-boil is good to ~250 F. The pressure is more-effective than the antifreeze at raising the boiling point.