Radiator construction

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yellow rose

yellow rose

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Let's discuss the benefits and drawbacks of copper/brass radiator verses aluminum construction. Cost, weight, cooling ability, durability and anything else that comes to mind.

And maybe those in the know can educate us on why aluminum likes fewer, bigger cores, while copper/brass likes more, smaller cores.

TIA
 
This topic may be cover a little too wide a range of subject matter. I'm going to stick with aluminum vs Copper/brass for starters.

Also, one can have literally the opposite viewpoint on this and still be right! There are so many factors that contribute to cooling, there is no 'correct' answer.
From a scientific standpoint, Copper is better at dissipating heat than aluminum. The problem with copper is that it is too soft to make a radiator out of. So additional material is added to the copper to make Brass. Once this happens, Aluminum becomes better at dissipating heat than brass. Aluminum is also stronger than brass which seems impossible because it is so light and seems to dent easier.

Now you have to apply this to various design radiators and various material of radiators. This is where things get very complicated as vehicle specifications, price and functionality are added to the equation.

One thing to point out early on in this topic. Aluminum has been used by OEM mfg's in higher end vehicles for many many years. The reason they were not used in everything is mostly due to cost reasons. Historically aluminum has been much more expensive to harvest and to then fabricate. In the last 10-15 years, aluminum pricing has dropped significantly, robotic tig welding has become available and affordable and at the same time the price of copper (the main ingredient in a traditional OEM radiator) has gone up in price dramatically. Hence why literally ALL new car/truck radiators are now made of aluminum cores. The tanks are commonly plastic and epoxy'd on. This is done as a cost saving measure. Otherwise, the tanks would be aluminum as well.

Let the fun begin! :)
 
AL has superior heat dissipation besides straight copper and is more economical to produce. copper is best, AL is about 50% of copper and brass is 50% of AL. Im sure a copper/brass alloy would be up there by AL too but it costs more to produce. AL is also lighter weight. Copper/brass has solder in it that may contain lead, no good for today. "...The aluminum radiator is 100% aluminum furnace brazed without any insulating solder. That is why aluminum radiators work better than copper ones. If you could build a copper radiator the exact same way we make the aluminum ones, it would work better than the aluminum. It would also weigh about 90 pounds..."
WHY DO ALUMINUM RADIATORS COOL BETTER THAN COPPER? – DeWitts™ Direct Fit® Aluminum Radiators
 
Ccas said:
This topic may be cover a little too wide a range of subject matter. I'm going to stick with aluminum vs Copper/brass for starters.

Also, one can have literally the opposite viewpoint on this and still be right! There are so many factors that contribute to cooling, there is no 'correct' answer.
From a scientific standpoint, Copper is better at dissipating heat than aluminum. The problem with copper is that it is too soft to make a radiator out of. So additional material is added to the copper to make Brass. Once this happens, Aluminum becomes better at dissipating heat than brass. Aluminum is also stronger than brass which seems impossible because it is so light and seems to dent easier.

Now you have to apply this to various design radiators and various material of radiators. This is where things get very complicated as vehicle specifications, price and functionality are added to the equation.

One thing to point out early on in this topic. Aluminum has been used by OEM mfg's in higher end vehicles for many many years. The reason they were not used in everything is mostly due to cost reasons. Historically aluminum has been much more expensive to harvest and to then fabricate. In the last 10-15 years, aluminum pricing has dropped significantly, robotic tig welding has become available and affordable and at the same time the price of copper (the main ingredient in a traditional OEM radiator) has gone up in price dramatically. Hence why literally ALL new car/truck radiators are now made of aluminum cores. The tanks are commonly plastic and epoxy'd on. This is done as a cost saving measure. Otherwise, the tanks would be aluminum as well.

Let the fun begin! :)
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Can you expand on your comment on why aluminum want fewer, bigger cores and C/B wants more, smaller cores?
 
I've been running the aluminum, cheap "Champions" in my past few classics. I've had zero issues as far as leaks and cooling. As far as answers, I'll let the others wager in
 
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Something i have noticed about modern car AL radiators...

They have signifigantly more area per cubic inches of engine.

They are a real cross flow, in (or out) at the upper corner and out (or in) at the oppisite lower corner
 
yellow rose said:
Can you expand on your comment on why aluminum want fewer, bigger cores and C/B wants more, smaller cores?
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I can only comment on our research with 2, 3 and 4 row aluminum.

1. In air flow tests, the ridges in between each row create turbulence. A 2 row only has one ridge and a lot of essentially 'straight-away' to gain air speed over each tube. a 3 row has 2 ridges that create turbulence and a 4 row had 3 ridges that create turbulence. In both the latter cases, the 'straight-aways' are shorter. So it takes a lot more pulling to get the same amount of air flow through the radiator.
2. If you add up the total dimension of the 3 and 4 row radiators, they don't add up to a 'big 2 row'. So the 3 and 4 row radiators simply don't have as much volume of fluid passing through them.

So for these reasons, Big 2 rows are always more efficient. In fairness to these brands that have chosen to market small 2, 3 and 4 row rads, for many owners they get the job done just fine. Especially in highway driving where air flow is plentiful. My point has always been, why take a chance that you are the guy that, for whatever reason, your engine needs that little bit extra capacity and efficiency. Then you will be thinking that extra $100 bill (over small 2 or 3 row) you saved, wasn't such a good savings.

btw, 4 row aluminum radiators are around the same price as most big 2 row. So if you don't already own a 4 row aluminum radiator, I see no logical reason to ever buy a 4 row. It has zero advantages.
 
Just my thoughts...

I think the size of the cores in aluminum vs. brass radiators has to do with how wide of a tube is physically possible to construct out of each material. IIRC it was only in the past 10-15 years technology reached the point where you can make big 2-row core aluminum radiators inexpensively; I have one in my Duster (made by ECP), the tubes are almost 1" wide it's quite impressive and both the tanks are aluminum as well, welded to the core all the way around. I think brass just doesn't have the right material properties to be made into a wide, flat tube and not be very weak puncture-prone.

I'd also say the durability of aluminum is much higher than brass; brass is super soft and can be punctured easily, also usually quite thin in radiators to keep the weight and heat retention down. And aluminum can be easily welded and patched, brass not so much it needs to be brazed which doesn't really actually fuse the metal back together.

I know the big weak point on modern OE rads are the stupid plastic tanks, that is the point where they ALWAYS fail. Replaced the rad twice in my Jeep and once for a friend's 2000 Durango 5.9, each time it had developed a leak between the aluminum core and plastic tank.
 
yellow rose said:
Let's discuss the benefits and drawbacks of copper/brass radiator verses aluminum construction. Cost, weight, cooling ability, durability and anything else that comes to mind.

And maybe those in the know can educate us on why aluminum likes fewer, bigger cores, while copper/brass likes more, smaller cores.

TIA
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It doesn't really matter for any of the projects I work on, either work just fine. Race cars usually get an aluminum radiator while street cars and resto mods get the factory style. I put a factory Cordoba radiator in my '72 Duster just because it looks original that way. I don't think I'll have any trouble keeping the big block cool with the factory radiator and it looks stock. A lot of aluminum radiators look like a Pep Boy mess under the hood. I prefer a cleaner look on my projects.
DSC_3645 (Large).JPG
 
While on the topic, how much engine could be effectively cooled with a two core brass copper radiator using a PRW water pump, a fully shrouded 18 inch six blade clutch fan, all driven at 22-1/2 percent overdrive (CFV serpentine alternator only kit)?
 
AndyF said:
It doesn't really matter for any of the projects I work on, either work just fine. Race cars usually get an aluminum radiator while street cars and resto mods get the factory style. I put a factory Cordoba radiator in my '72 Duster just because it looks original that way. I don't think I'll have any trouble keeping the big block cool with the factory radiator and it looks stock. A lot of aluminum radiators look like a Pep Boy mess under the hood. I prefer a cleaner look on my projects.
View attachment 1715359396
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I painted the top tank of my aluminum rad black for that reason, looks weird having a big shiny aluminum part in a not-so-clean-and-shiny engine bay lol. I also lightly sprayed the front of the core because I hate seeing anything behind the grille... too many resto jobs have body color and shiny metal parts behind the grille and it looks like crap, your eye is drawn to what's behind the grille instead of the grille itself.
 
Something that I haven't seen talked about is the inside surface area that the coolant is in contact with in the tubes and the number of fins per inch.

If you have a 2 row 1 inch deep by 1/8" wide tube you will have less surface area for the coolant to contact than a 3 row 0.67" deep by 1/8" wide tube. (approx 4% more surface area to contact, 4 rows @ .5" deep ~7% more surface area) (inside perimeter of the tube, times length of tube, times number of tubes)

The number of fins per inch, at some point the more fins will restrict airflow but the more fins per inch, the more surface area for the air to pull heat out of the fins and the more surface area the fins are contacting the tubes.
 
Anyone can solder a brass radiator if it springs a leak. I started doing that when I was 16 and I still do it. You only need a decent sized soldering iron and some flux/solder. For that reason I vote for brass. Also, brass radiators will usually look almost stock.

To repair an aluminum radiator you need a TIG or MIG welder, which of course means you need the argon too. Most of us don't have that equipment.
 
69-340,
Funny you should say that as I was thinking about chiming in. As a welder I always pick aluminum as it is so easy to heliarc for modifications and repair. As a racer my default setting is invariably weight. I can braze and solder like a bandit but tig on aluminum is just so easy for me. Just goes to show you what a varied group we are as I am thinking of course I have argon in the shop! These threads while widely varied in response never fail to educate me in one aspect or another of our hobby. Thanks for so many of you on here with some serious knowledge. FABO rocks!
 
I like both the above comments because brazing does require a lot less equipment but I personally know how to TIG weld aluminum (I don't have the equipment but a friend does) and have done it more than brazing so I'm more comfortable... probably due to me being younger and not having been around much stuff that needs brazed.

I'm lucky we still had welding shop class at my high school before I graduated (2009) so I was able to learn the basics of all this stuff.
 
MopaR&D said:
I like both the above comments because brazing does require a lot less equipment but I personally know how to TIG weld aluminum (I don't have the equipment but a friend does) and have done it more than brazing so I'm more comfortable... probably due to me being younger and not having been around much stuff that needs brazed.

I'm lucky we still had welding shop class at my high school before I graduated (2009) so I was able to learn the basics of all this stuff.
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You are spot on, the last 1/2 dozen welders I have hired have no idea how to braze. To them if it is cast iron and broke it is a throw away item. I am also seeing a migration away from stick welding in our field. The young guns are all about wire feed.
 
Sublime one said:
You are spot on, the last 1/2 dozen welders I have hired have no idea how to braze. To them if it is cast iron and broke it is a throw away item. I am also seeing a migration away from stick welding in our field. The young guns are all about wire feed.
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I loved stick welding back in HS but I agree, very unpopular then and even more now. Everyone I know who wants to weld goes with wire feed, or if they want to get fancy go for the TIG. Gas and stick welding are just considered "old school" nowadays. But if you need a beefy weld on some fat material stick welding kicks butt.
 
You don't braze a brass radiator, Soldering is what is used. Brass radiators are soldered together, and this is also how you repair them.
 
69_340_GTS said:
Anyone can solder a brass radiator if it springs a leak. I started doing that when I was 16 and I still do it. You only need a decent sized soldering iron and some flux/solder. For that reason I vote for brass. Also, brass radiators will usually look almost stock.

To repair an aluminum radiator you need a TIG or MIG welder, which of course means you need the argon too. Most of us don't have that equipment.
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LOL. I broke the mounting tab off the radiator in my first car, a 72 Demon. Took it by the shop that my dads friend owned and showed him. He took out an ancient looking soldering iron, heated it RED hot with his torch and then soldered the bracket back on. Only charged me a 6 pack of ginger ale. Later found out he got drunk that night and slept on the shop. The ginger ale was for his whiskey. His wife had every store in a 2 mile radius not selling him ginger ale.
 
yellow rose said:
LOL. I broke the mounting tab off the radiator in my first car, a 72 Demon. Took it by the shop that my dads friend owned and showed him. He took out an ancient looking soldering iron, heated it RED hot with his torch and then soldered the bracket back on. Only charged me a 6 pack of ginger ale. Later found out he got drunk that night and slept on the shop. The ginger ale was for his whiskey. His wife had every store in a 2 mile radius not selling him ginger ale.
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That story and two weeks of physical therapy and diagnostics for bad discs at c5-c6 to t1-t2 is is making me crave a good stiff drink now.
 
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I had an aftermarket 2 row aluminum radiator in my 68 when i plowed into a damn deer in the middle of the night in the middle of nowhere. The radiator was bent into a banana shape and the fan beat the **** out it before i got stopped. I bent the fan blades back and drove on home, no leaks. No way a brass one would have survived that. Im sold on the aluminum ones
 
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