Cooling Advise

[hemidude426ci]

Im running a 440-6 stroked to 500 with a roller cam in my 'Cuda.  Ive had a be cool aluminum radiator in my car, as well as the factory fan and an electric fan thats always on in the front of the radiator.  The car never runs at a consistant 180, closer to 210 even when its 60 degrees out with a breeze and cruising on the freeway. Any suggestions? Would a factory 3 core be better? I just want it to be drivable.

[MTS-Challenger]

First off, Mopar Big Block engines are notorious for running hot as these engines make alot of heat. 190-210 degrees is about normal (remember the thermostate does not until 180)

So let's cool things off -

Yes the 26" factory 3 core is a start (not sure of what size your cool alum is) because of the top to bottom flow is much better than side to side flow. Second, dump the factory fan/shroud assembly and use an dual electric fan setup to pull the air thru the radiator (a pushing fan does very little unless you have air conditioning, so dump this also) and make sure the electric fan setup have a full body shroud that covers the whole radiator area as we want to draw air thru ever inch of radiator for max cooling.

Now the important part, pressure test the system... any air leaks in will always cause over heating. Just because water does not leak out means the system is not drawing in air thus boiling the water. Ive seen alot of freeze plugs and radiator caps cause this problem time and time again.

 Enjoy! 

[Chryco Psycho]

Actually I disagree , virtually everytime you switch to electric fans you have problems , the factory 7 blade clutch fan will pull more air than the electrics & put less load on the engine as the fans will draw a lot of current

[Jim]

 

Actually I disagree , virtually everytime you switch to electric fans you have problems , the factory 7 blade clutch fan will pull more air than the electrics & put less load on the engine as the fans will draw a lot of current

I'm with CP on this. Electric fans are generally a band aid for another problem. Reasons to use electric fans are packaging constraints prevent fitment of a direct drive fan, and lower HP consumption. That said, electric fans that can move enough air are going to require electrical system upgrades.

[72cudamaan]

I agree, 7 blade with a proper fitting shroud and correct placement of the fan to shroud is the
best plan of action. Check the rad cap. Most people overlook this simple little device.

[Bullitt-]

Nobody mentioned the tune or vacuum leaks, running lean or out of time will cause overheating.

[Chryco Psycho]

awe c'mon neal  I know you like to stick to simple stuff but I like my new custom setup for the dart... double pass radiator with dual 14"

 Nice looking system as long as it keeps things cool !!
 I know 4C has had constant problems with his , serp belt system so no room for a fan & it runs hot .

[BS CUDA]

Nice looking system as long as it keeps things cool !!
 I know 4C has had constant problems with his , serp belt system so no room for a fan & it runs hot .

  I installed electric pump and fan last September (to gain a 10th  ) and the car suddenly overheated in traffic - I had to crank the fans on high in staging with car off after a pass to cool. Peeled that crap off this spring returned to stock fan and pump and car is back to running cool again everywhere. As for big blocks running hot - I have heard this but have never had an issue with stock cooling. 

[Chryco Psycho]

Yeah 4C is running twin electric fans & an alum rad , no room for the clutch fan with the serp system .

[Strawdawg]

Normally, the problem with a cooling system comes from either too little coolant flow or too little air flow. 

With regard to too little coolant flow, we know there are some water pumps out there that have small passages that restrict water flow.  The 440 Source unit is one that has been reported thus...and some thermostats open slowly and don't open substantially at their rated temps.  If you have a high flow thermostat, you need to also have a good high flow pump that will build sufficient pressure in the engine to eliminate hot spots that will create localized boiling in the engine.  This then pushes steam bubbles into the coolant which reduces heat transfer.

On the air flow side, we can have a good radiator and block air flow at speed due to an improperly designed shroud that does not let the air out the back side of the core.  Some electric fan shrouds are bad about this.  The volume is too small due to a shallow depth in the shroud which tends to brick wall the airflow that comes in the front.  If you look at Sledge's pictures, he has two 14" fans that cover much of the surface area of the radiator and the shroud does not serve as an air block.  If it had two 10-11" fans, then it would have a far greater difficulty in passing air thru at highway speeds.   We also have the problem in that all fans may not be rated at the same head pressures so that the cfm ratings may not truly be comparable in a given usage.   Normally, good, high volume fans cost a lot more money than do cheaper fans even if the ratings are similar.  The amperage ratings of the fan can often be a better indicator than the factory rating of cfm.

At highway speeds, the car should run cool even without a fan or fans if the radiator is of sufficient size and they are sealed to the radiator opening so that air must go thru the core instead of finding a path around it.

Normally, a quality aluminum radiator of sufficient size will do a better job of cooling than well a factory non-aluminum unit due to the larger tubes that present much greater surface area to the air flow in spite of aluminum's lower coefficient of heat transfer.