Can't figure out my overheating issue

62MAX,
If your reasoning is true, why did Mopar design the cooling system for a big block applications with A/C with an overdriven water pump with 8 impeller blades? The reason for the 6 blade water pump is LESS horsepower being consumed which is OK for drag strip applications. Velocity is a determining factor for heat exchange...be it liquid to air or liquid to liquid or air to air heat exchangers. However, for liquid to air heat exchange, velocity, specific heat of the cooling media (both on the liquid and air side) as well as the surface area of the heat exchange component (the fins per inch) are important factors in determining just how efficient the heat exchange is. One must perform their own due diligence with regard to what is ultimately selected, rather than relying on a friend of the next door neighbors, brother-in-laws cousin..... but this is just my opinion.
Cheers,
RJ Renton

Ideally the coolant is achieving turbulent flow in both the engine passages and the radiator (both are heat exchangers). If more residence time is desired in the radiator then this should be achieved by more passes rather than slowing down the fluid. If slowing the fluid results in laminar flow then the benefit of more residence time would be lost. Throw a little corrosion into the mix and you have a less-than-ideal system.

We can all read up on heat exchangers and fluid flow so I won't go any further but there is definitely a science behind it. I think the point is, once an engine is modified then the original radiator design might not be suitable. New cars have electric fans and they have been designed to operate using the same principles the old mechanical fans were. Once you start changing things then you can either (1) guess, (2) go with someone else's solution or (3) go back to the drawing board!

RJRENTON said:

62MAX,
If your reasoning is true, why did Mopar design the cooling system for a big block applications with A/C with an overdriven water pump with 8 impeller blades? The reason for the 6 blade water pump is LESS horsepower being consumed which is OK for drag strip applications. Velocity is a determining factor for heat exchange...be it liquid to air or liquid to liquid or air to air heat exchangers. However, for liquid to air heat exchange, velocity, specific heat of the cooling media (both on the liquid and air side) as well as the surface area of the heat exchange component (the fins per inch) are important factors in determining just how efficient the heat exchange is. One must perform their own due diligence with regard to what is ultimately selected, rather than relying on a friend of the next door neighbors, brother-in-laws cousin..... but this is just my opinion.
Cheers,
RJ Renton

Click to expand...

You got it backwards,the A/C pump is six blade.View attachment 278493View attachment 278494

Had heating problems with electric stuff ,went to clutch fan and shroud,end of problems

All this talk of electric fans at highway speed is redundant. Even the fact you thinking it will not over heat sitting still is absurd. Just try letting it sit there with the hood closed and see what happens. You put in a big radiator and installed a shroud with a small outlet and it does absolutely nothing for air flow. The fans regardless whether mechanical or electrical will only pull or push what air is available in the direct path of the fan if you are placing them at the radiator that is not a big area. Moving the fan out to the shroud entrance will pull air off the whole radiator. Look at any factory setup and that is what you will see. At highway speed the shroud should not even be needed even if sized correctly it is only there because of its low speed fan enhancement function.

I fought overheating on a 440 for a while. Here are the things I did to remedy my problem:

1. Dialed in 36 deg BTDC total timing (probably the one item that had the most effect on temp for me)
2. Installed lower radiator hose with metal coil inside to prevent collapse at high RPM
3. Moved transmission lines from radiator to separate trans cooler
4. Replaced after market aluminum water pump housing (smaller openings) with original cast iron water pump housing
5. Installed Miledon water pump
6. Installed Mr. Gasket High Flow 180 Deg thermostat
7. Installed 3 core Champion radiator with dual electric fans

Now 440 Challenger runs all day long at 180 deg in super hot Florida summer weather!

Hope this helps.

Welp! I just installed my radiator today after having it cleaned out and also drove my car appx 40 miles and it's safe to say no more over heating for me...thanks for you'll advice