Hot Big Block?

[debbiedowner]

Any help would be appreciated… just finished a 10 year project restoring my 74 challenger. We went with a big block 440. The issue that we’re running into is the motor is getting hot. We’re running a Cold C big block radiator and two 12inch fans rated at 2800 cfm total. We have tried a 160 and 180 thermostat. We also tried a mixture of 74 and 77. We know we have good flow but it just seems like the motor is heat soaking, especially on the days when it’s 100 degrees outside. The motor will hang around 180 for a while and then begin to creep towards 195-200. As we drive, it will hold around that 195-200 range. Are we truly running “hot” or is it okay? If it is not okay, what else can we do?

View attachment IMG_7961.jpeg

 

[6PKRTSE]

That is okay, that is about where my red Charger runs temp wise. Never any issues in 37 years and over 254,000 on this car now.

 

[Xcudame]

Put a 195°F thermostat in it. 180°F is definitely the bare minimum thermostat temp I'd ever use. Also, 200°F isn't that hot. With a 16 psi pressure cap, 100% water won't boil until ~250°F. A 50/50 mixture is actually best! Water dissipates heat very well!

 

[6PKRTSE]

Agreed. My newer vehicles all run at 210-215.

 

[Spyder]

Nope, I wouldn't be worried about it at 200.

 

[Orangedog70]

Any help would be appreciated… just finished a 10 year project restoring my 74 challenger. We went with a big block 440. The issue that we’re running into is the motor is getting hot. We’re running a Cold C big block radiator and two 12inch fans rated at 2800 cfm total. We have tried a 160 and 180 thermostat. We also tried a mixture of 74 and 77. We know we have good flow but it just seems like the motor is heat soaking, especially on the days when it’s 100 degrees outside. The motor will hang around 180 for a while and then begin to creep towards 195-200. As we drive, it will hold around that 195-200 range. Are we truly running “hot” or is it okay? If it is not okay, what else can we do?

View attachment 142996

View attachment 142997

Just to double check it, try a Mr. Gasket Thermocap on the radiator. See what that shows.

 

[Chryco Psycho]

Electric fans generally do not move as much air as Clutch driven mech fans , also at speed the electric fans can actually block air flow .

 

[Orangedog70]

Electric fans generally do not move as much air as Clutch driven mech fans , also at speed the electric fans can actually block air flow .

True dat.

 

[6PKRTSE]

True dat.

Mine move a ton of air. Mine actually blow your pants legs if standing like 10' behind the car while they are on. I think they are like 4600 cfm. It is the coolest runshroud. On the street in my fleet and makes more than double the horsepower than my next highest horsepower car does. Runs much cooler than my more stock vehicles with stock fans and shrouds.

 

[Orangedog70]

Mine move a ton of air. Mine actually blow your pants legs if standing like 10' behind the car while they are on. I think they are like 4600 cfm. It is the coolest runshroud. On the street in my fleet and makes more than double the horsepower than my next highest horsepower car does. Runs much cooler than my more stock vehicles with stock fans and shrouds.

View attachment 148228

View attachment 148229

It's all about putting the right combination of parts together. Yes, the modern fans, & accessories are better than the old stock parts but there are a bunch of good updated mechanical parts available now. I worked at a performance & restoration shop for decades & have seen many Mismatched electrical fan kits that have had cooling issues. It just depends on who or what shop is designing the cooling system.