Cooling Problems

[74LIFE]

What is the best radiator fan combo, copper vs aluminimiun been running bronco on offroad track 3 laps 220 temp need help please. looking at 4 core coopper rad eletric fan or 7 blabe fixed fan. any advice very helpful. stumped? gonna buy new.

 

[wildbill]

I would think the flex fan will be better than the elec.typ. Also a copper rad. is better than alum for cooling good luck. Bill %) ;D

 

[Broncobowsher]

The best, Cupobrazed copper radiator. It is a copper radiator that is brazed with a copper alloy instead of lead/tin solder. Copper makes a great radiator, Aluminium is very good as well. Coppers fault is that the solder that holds it all together is horrible for a radiator. It's better then no connection, but not as good as one parent metal such as copper or Aluminium.

That puts traditional copper radiator and Aluminium radiators very close to each other. At this point it's whoever makes a better raidator. A cheap copper isn't as good as a nice Aluminium. A cheap Aluminium isn't as good as a good copper. IF you have issues with dirt/mud clogging, larger fin spacing helps let the junk pass through, but that hurts cooling. But any cooling is better then no cooling if the radiator is clogged with mud and dirt.

Thicker cores and cores with tighter fin spacing (more fins per inch) make it difficult for air to travel through the core. This is where good fans come into play. CFM ratings are BS! Those numbers are done without any restance. Those high CFM electric fans choke when you put a radiator in fromnt of them. It takes a good fan to pull a vacuum to force air through the core. It's a pressure differential that must occur to move the air through a radiator. At speed, proper aerodynamics is all that is needed for that pressure differential, at low speed it takes a fan. Get the aerodynamics wrong and you will always need a fan.

 

[00gyrhed]

Big bag of worms you opened here. You will get a lot of opinions. The fact is all you have to do is enough to keep from overheating.

Before you go chasing after problems make sure the gage you are using is right. Check it with a good thermometer that is known to be correct. Put it in boiling water and verify that it reads 210 +/-. I am not sure about the altitude correction for IND. Also check it by putting it in a mixture of ice and water. It should read 32 +/-. You don't want to spend a bunch of money for no reason. I have two brand new temperature gages (one SW and one autometer) and one old autometer gage in my shop. Not one of them is right. The old autometer gage reds 246 when the actual temp in 185. None of the them are withing 10 degrees of being right. My old Bronco gage read 18 DEG low. My new Norsdogg electronic gage reads 7 degrees high.

Your cooling system only needs to be as good as it needs to be. Anything else beyond some reasonable safety factor is a waste of your money that could be spent somewhere else.

I had my three row core replaced with a high eff 4 row when I drove a limb through it. A local shop did it for much less than any of the vendors would sell a new one especially with shipping. I prefer brass to aluminum. For several reasons, but ultimately I believe the brass will out last the aluminum.

I took the opportunity to put a fan clutch in and made a shroud.

Make sure you have at least a 15# new radiator cap and a burp tank, and that it actually works.

You will get the most air flow at idle with a shroud and one of the high flow 7-blade fans that BC and others sell. But this set up will restrict airflow at high speed. My Bronco is much quieter with the clutch and fan and has more low end torque available right off idle. It is questionable as to weather the clutch and 6 blade fan I am using would use enough air without the core change.

195 DEG t-stats are better than 180 or 160 if you are having problems overheating.

Some people also will have a 2" longer core put in between the two tanks.

3 laps of hard use takes it to 220? That really doesn't sound too bad if it is not continuing to rise. Remember, you are not overheating until you boil water out of the radiator system. A 50-50 mix water to antifreeze will not boil at 250 DEG under 15 PSI of pressure so you are still OK. Some auto maker idiot lights don't even light up until 250 or so. As long as you are circulating coolant you are not overheating and 250 DEG water will not hurt anything in your engine. Running at some temperature below that is safety factor for unusual operation such as long hill climbs or heavy traffic. If you are using you engine as hard as you ever will and it climbs to 220 and stops it is probably good to go.

 

[00gyrhed]

THis was added while I was typing

The best, Cupobrazed copper radiator. It is a copper radiator that is brazed with a copper alloy instead of lead/tin solder. Copper makes a great radiator, Aluminium is very good as well. Coppers fault is that the solder that holds it all together is horrible for a radiator. It's better then no connection, but not as good as one parent metal such as copper or Aluminium.

That puts traditional copper radiator and Aluminium radiators very close to each other. At this point it's whoever makes a better raidator. A cheap copper isn't as good as a nice Aluminium. A cheap Aluminium isn't as good as a good copper. IF you have issues with dirt/mud clogging, larger fin spacing helps let the junk pass through, but that hurts cooling. But any cooling is better then no cooling if the radiator is clogged with mud and dirt.

Thicker cores and cores with tighter fin spacing (more fins per inch) make it difficult for air to travel through the core. This is where good fans come into play. CFM ratings are BS! Those numbers are done without any restance. Those high CFM electric fans choke when you put a radiator in fromnt of them. It takes a good fan to pull a vacuum to force air through the core. It's a pressure differential that must occur to move the air through a radiator. At speed, proper aerodynamics is all that is needed for that pressure differential, at low speed it takes a fan. Get the aerodynamics wrong and you will always need a fan.

AMEN to the electric fan comments. Avoid them if you are having problems, they usually compund problems not fix them. My buddy put a pusher in front of his. It actually restricted his air flow. Mechaincal engineers that design HVAC systems deal with this kind of stuff all the time.

 

[Roli]

Good thread. I'm a new bronco owner and my 76 302 was running at 220 and I was worried. I pulled the radiator and had it worked on and now it seems that my gauge is broke, it's jumping like CRAZY!

 

[Broncobowsher]

Good thread. I'm a new bronco owner and my 76 302 was running at 220 and I was worried. I pulled the radiator and had it worked on and now it seems that my gauge is broke, it's jumping like CRAZY!

Make sure the engine is actually full of water and not low

 

[broncnaz]

I had a 4 row radiator it always ran hotter then I liked when crawling and at speed. I went to a BC HD 3 row and dont run over 190 but I'm not racing either. I also run a flex fan.
If your racing I would think that you could trim out the wheel wells to help get some of that hot air out of there. Along with a functioning hood scoop or louvers in the hood will help reduce the temps. One other thing is that plain water actually transfers heat better than a anitfreeze mix but you do give up the luberication and higher boiling temp without anti freeze.

 

[74LIFE]

thank's guys a lot of good advice, looking into it more i noticed my shroud had cracked and the bottom had fallen off. i have a three inch body lift so i had to split the shroud to accomidate the fan. i will try the thermometer test to day. heading up to silver lake MI. this weekend hopefully i can get this issue resolved, are there some post on here about making homemade shrouds thanks again. ill keep you posted on my developments.