Thread: Aluminum radiator question

Tweet

Back when aluminum radiators were becoming popular and coming down in price I did some reading up on them. What I remember reading was basically while aluminum does not transfer heat as efficiently as brass copper, because it’s more rigid the tubes can be made wider allowing for more surface area and better cooling. Basically the more surface area the coolant is exposed to, the better the radiator will cool.

Most of the earlier aluminum radiators I can remember seeing were 1 or 2 row with 3/4” to 1” wide tubes. I’m now seeing 4 row aluminum radiators being advertised, but usually with only 3/8” tubes.

OK, here’s the question for you guys. All other things being the same (number of rows of tubes, fin count, size etc) would you choose 4 row radiator with 3/8” tubes (1 1/2" surface area per row of tubes), or a 2 row radiator with 1” tubes (2” surface area per row of tubes) ?

Am I missing something about the efficiency of the 4 row aluminum radiators?



.

copper brass they say it.s the lead holding heat transfer back or bedding the header cores in epoxy .3 or 2inch wide rows work better then 4 per rows . if the radiator is the same width . there less dead spot.s on the core when air cross the core and more surface in play they say. all this only works if the fins per inch are about the same if your going to compare any radiator to another. price on core can cost more if there not a comon size cost of tooling in the past a filler or spacer was used by some to make use of a more popular core that could be used and still be a drop in fit .price drop? i do not think so but there is more and more builder of street rod. hot rod. rads as they have made more core sizes as most all of the after market rads were based off OEM cores most all the one 20 years ago were ford cores .i think it not to big or a deal going two a wider copper tub as i have a wide copper tube rad in the chevy . i am sure there is rules to all of this and copper starts getting heavy . i use alot of They,s in this post as some of this is what some of guy that built them told me .if you see were i live then you may know who the they are?

Basically the flow is what you want in a radiator if the motor is making HP. A 2 row of 1" tube will flow better than 4 rows of 3/8. If you think about it, 2 rows of 3/8" is not at wide as 1 row of 1".
Yes......copper/brass does dissipate heat better, but there are other components in a copper/brass rad. Mainly the lead solder holding the steel tanks. There are more metals involved in a copper/brass rad, all dissipate heat at a different rate.
Aluminum rads work better with the wider tubes ,1. because they will flow better and 2. since the tubes are wider and the fins per inch are more, you have more air flow over them helping to remove heat.
There are aluminum rads that do have epoxied cores to the tanks...Griffin.....They do work well as I had one on my pro street car for 9 yrs with no problems. The downside is you can not weld on them. I always tell my customers to get an aluminum rad with all welded tanks. Then if you need to weld a tab somewhere, you can.
The one bad thing I will say about a wider tube aluminum rad is watching how much pressure you generate within your cooling system.
With wider tubes and too much internal pressure, you can actually balloon the tubes inside. What happens then is as one tube balloons it closes off the one on top and the one below it. If it happens to a few tubes, all of a sudden you have very little flow in the radiator itself. I had a customer who had a blown Willys with heating problems...........he brought the car to our shop and when we looked at the radiator, you could visibly see between the fins the tubes were balloned. It doesn't happen much but it does happen.

air locks are hell on tubes and yes you have to watch your pressure on the caps . the epoxy bedded tubes to header frames. tanks are and can still can be welded on carefully. i had a epoxy Howe radiator with welded headers. in my 475bbc 1/2 filled block cid gto 20 years ago was a ford core yes they do work ok

If you are having heating problems and would like to go to an aluminum radiator, " smart money " would be to invest in a custom built dual or tripple pass radiator. With these types of radiators, the water remains in the radiator for a longer period of time for better cooling. A company like Mattson's Custom Radiator could steer you in the right direction. Their phone number is (714) 893 4900

I would not use a double or triple pass radiator for the street. There is a big misnomer when it comes to "keeping the coolant in the radiator for a longer time so it cools". The problem is this.............if the coolant is sitting in the radiator for a longer time...what's happening for the coolant waiting to come into the radiator? What is happening is the coolant in the block is getting much hotter.
You want coolant to keep moving in the system. The better it moves, the better it cools.

the man who use to build all my rads always said it comes down to air movement. the tow truck guys would always want 4 rows or more. he would build them a 3 row rad with a z-ore that you could read through. problem solved. since he went away i tried some of the aftermarket brass. nothing but heating problems. went to the 2 row aluminum and never looked back. the be-cool in edwards 37 is barely the same size as the a/c condenser. only 14 in wide but cools just fine in the texas heat.

I think there is a problem with sunset dart's logic. with the same flow rate "GPM", you are still pumping the same amount of coolant out of the block, the coolant does not sit in the block waiting it's turn to get into the radiator. The coolant takes more time to flow through the radiator. higher capacity radiator

66.............a double and or triple pass radiator has dividers inside the radiator. The coolant goes thru the top half of the rad then it drops down and flows over the spacer to a hole where it starts again the flow. The problem is the time it takes. I guess I didn't quite explain it as well as I should.
It all comes down to flow and you want the flow not interrupted in a cooling system. A double or triple pass has interruptions in them.
Double and triple pass radiators work well in an all out race car. And yes, I have seen and talked to some guys who do run them on the street. But I have always heard them complain on how much hotter there motor runs as well.

Double tripple pass are for constant high RPM stuff like NASCA or SCCA kind of stuff.
Tube size mostly depends on radiator style. Top flow works best with smaller tubes. The cross flows work better with larger 1' to 1 1/2" tubes.
The main reason is the top flow radiators need a restriction to help prevent coolant at higher RPMs frome running a path of least restance from the inlet to the outlet and basicly bypassing a majority of the radiators cooling area.
The cross flows dont have the same issue it has to flow from side to side. So the flow restriction isnt needed. Increase in flow allows more water to be exposed to the cooling area and sent back into the engine.

you can pump water as fast as you want but unless you get good air flow it is a mute point. 4 to 4 1/2 in rads will almost always run hot at idle. the z cores i use to run were only 2 1/2 inches thick. never had a heat problem to speak of . but after my guy retired i went to after market but then went aluminum .