Thermostats and Rad Caps

[Jack_440 Savoy]

What is everyones choice when it comes to Thermostat Temperatures and Rad Cap pressures ??? I am thinking 195 degrees and 16 PSI.

[dwc43]

It does not matter what stat you run as that only determines how fast it heats up. As long as max temp is 200* it's fine. I run 15 and 16 lb caps on street cars, but I run 20 to 24 on my race cars. Helps lower the boiling point so it wont over heat. The main thigns to look for in a cooling system that causes overheating is the rads condition, size, aluminum or whatever yours is made of, rotating speed of the water pump, timing and carb jetting. Any of those are the most likely cause of overheating along with the use of a good cap at the correct pressure.

[cudabob496]

Originally Posted by dwc43

It does not matter what stat you run as that only determines how fast it heats up. As long as max temp is 200* it's fine. I run 15 and 16 lb caps on street cars, but I run 20 to 24 on my race cars. Helps lower the boiling point so it wont over heat. The main thigns to look for in a cooling system that causes overheating is the rads condition, size, aluminum or whatever yours is made of, rotating speed of the water pump, timing and carb jetting. Any of those are the most likely cause of overheating along with the use of a good cap at the correct pressure.

I was using a 160 stat, but when I went to a 180, the engine felt more powerful. The aluminum heads I have like the 180, as it puts more heat into the combustion chamber. I think my cap is a 16 pound also. Because of the aluminum radiator I have, the engine will run at whatever thermostat setting I have. With the 160 stat, the engine coolant temp was 160 to 170 while tooling down the road. Now with the 180 stat, it is 180 to 190 degrees.

[dwc43]

Originally Posted by cudabob496

I was using a 160 stat, but when I went to a 180, the engine felt more powerful. The aluminum heads I have like the 180, as it puts more heat into the combustion chamber. I think my cap is a 16 pound also. Because of the aluminum radiator I have, the engine will run at whatever thermostat setting I have. With the 160 stat, the engine coolant temp was 160 to 170 while tooling down the road. Now with the 180 stat, it is 180 to 190 degrees.

That's because your system works better than it should for what you have. And if your compression is low enough then the extra heat will help. I also found that more temp in a slant six I had years ago made more power in the spring and fall, but during the summer anf winter months months it caused it to fall back off. Weather does play a part in a coolign system as well, and in the case mentioned above it effects tunning quite a bit too.

[Jack_440 Savoy]

I am Not sure but I think it may have been in Don Dulmage's book " Old Reliable" where it said 195 degrees is the best temp for performance . But I am not sure and I can't find that book.

[cudabob496]

Originally Posted by Jack_440 Savoy

I am Not sure but I think it may have been in Don Dulmage's book " Old Reliable" where it said 195 degrees is the best temp for performance . But I am not sure and I can't find that book.

Seems that would be dependent on so many things, such as cam, compression ratio, material of the head, coolant flow through the head, exhaust setup, rich or lean fuel ratio, type of plugs, design of head and combution chamber, if you want max torque or hp, etc etc. There's always an optimum coolant temp for power. Basically, try several thermostats and see what the "seat of the pants" tells you.