Over heating-aluminum vs copper radiators

Steve Thanks-- Timeing !! see last post as to details
In trying to solve my overheating problem when running 50 mph {245*} with V6 in 58 CJ stock trans. I have done all the normal checks, flushes,refill, replaced or inspected pump,thermostat, have electric fan with shroud, no air bleed around, 3 core new radiator copper, temp ok upto 45 mph{190* w 180* Tstat} top speed is 54mph, sometimes on the open road 45 just isn't fast enough..

I found this artical, what say you all- True or BS????

"From what I have seen, it is very difficult to directly compare most aluminum and copper/brass radiators. I have a very difficult cooling job on a twin turbo 340cid V8, that has a fully packed engine compartment and not a lot of space for a radiator. I have tried several versions of both copper/brass and aluminum, and I think the design differences had more to do with the results than the materials.

Here is what I found:

3 core copper/brass cooled well at speed, not well at idle

4 core copper/brass cooled better at idle, but worse at speed than the 3 core

Single (1.25") core aluminum, cooled OK at speed and not well at idle

2 core (1.25"X 2) aluminum cooled extremely well at speed, and a bit better at idle than the single core.

I would rate them this way:

At speed from best to worst 1. two core aluminum 2. 3 core copper/brass 3. tie between single core aluminum and 4 core copper/brass

At idle from best to worst 1. 4 core copper/brass 2. tie between 2 core aluminum and 3 core copper/brass 3. Single core aluminum

The results lead me to believe that how the tubes and fins are laid out, and how dense they are, make more difference than what they are made of. The radiators that had the lesser resistance to airflow, because of less fins and/or thickness, did better at speed because they allowed more airflow through the radiator. The radiators that did best at idle, had more fins and/or thickness, that could dissipate the heat better at the low airflow rates at idle.

The aluminum radiators use big tubes and wider spacings of tubes and fins, so they can allow a lot of air through. If you can supply the air, they will cool extremely well. The copper brass use smaller tubes (burst strength issues) and high density finning, so they perform better at lower airflow rates, but you can't put enough air through them to get bigtime cooling.

My final solution was to use the 2 core aluminum radiator, which gave outstanding cooling at speed. To address the idle heat up issue, I made a pulley that would spin the fan at 1.3 times the speed I had, and added a viscous clutch to get rid of the added drag at speed. The extra airflow made the aluminum 2 core out perform all the others at idle.

 

Intresting info you posted.

However.. I dont know what your problem is. I've heard of people having problems getting their :v6: to warm up !

Your 3 core rad should be more than enough.. what application is it out of ?

I find it odd that 5 mph increase causes the temp to increase so much. Usually when driving down the hwy at hwy speeds the motor runs cooler because of the amount of air being flowed though the radiator. What RPM's are you turning ?

I'm just throwing out ideas for you here.. If your cooling system is in good shape, perhaps your problem lies somewhere else. How is the motors compression ? low comp could make a motor run hotter. What kind of ignition do you have, and what is the timing set at ? Too much timing advance can cause a motor to overheat, maybe the extra 5 mph(rpm increase) is causing the timing to advance enough to overheat. What do you have for the fuel system ? Running too rich or lean may cause problems as well.

 

Don't forget the exhaust. If it's restricted, it will definitely run hotter.

 

Don't believe anything you read on the internet.

 

QUOTE=w3srl;857826]Sounds like there is another issue here besides the cooling system. Have you tried different timing settings? Not enough advance can make an engine run hot under load, and too much advance will cause detonation which also causes excessive heat.
QUOTE]
Steve;
I believe you nailed it on the head & this is the problem..it appears the Carter YF carb had some issues, to a point that the vacuum advance port become plugged so the PO found a different vacuum port to use:?, Watching the timing light - vacuum line disconnected & plugged timing set at 5* BTDC. reconnect vac. and spark advanced about 1" to 10* BTDC. As I increased RPM fast or slow the spark advance about 3.5" this would be about 35* BTDC not knowing the specifications and going of memories { which are failing} spark should have dropped back to the 5* BTDC mark direction.
Pulled the carb off to look at a rebuild and found some PO modifications. not going to mess with it. so any suggestions about a upgrade? have done searches of this forum and see Holley 2300, some motorcraft,? Not going to change intake so in searching summit no 1 barrels looking at 2 barrels with adaptor.
If it was yours what would you do? :v6:
and thanks again for all the help