Few questions on radiator tube size

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71DodgeDemon340

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Hey guys, so i will have to replace my leaking milodon water pump and figured while the coolant was all out it i was thinking of swapping out the factory style 22” radiator for a aluminum one, i already have the aluminum shroud from wizard cooling and was looking at getting one of their radiators. They offer both 1” tubes and 1.25” tubes? both have 16 fins per inch, is there such a thing as too big of radiator tubes? Right now with a mechanical fan and clutch and 180 degree t-stat in the summer i may see 195 with the factory style radiator
 
Bigger the better, but Make sure the width of an aluminum radiator will work for your setup. That has been a real issue for me.
 
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Bigger the better, but Make sure the width of an aluminum radiator will work for your setup. That has been a real issue for me.

the thickness of the factory style right now is right at 3” from mounting flange to where the shroud fastens, according to their dimensions the wizard radiator is 3” thick with both the 1” and 1.25” tubes
 
I'm not a fan of aluminum radiators. Copper cools better than aluminum. Aluminum doesn't look right to my eye in a 60's car.

If your cooling system is working right why change it?

If you need your radiator repaired or want a new OEM look here...

Glen-ray Radiators - All New Licensed Mopar Chrysler Dodge Plymouth Radiators


I was just thinking it would look better than the oe style

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Original Mopar radiators are brass not copper. Brass is a copper/zinc alloy.
Brass conducts heat almost 50% poorer than aluminum.

Don't beat me up. Above is from pg 55 of current Mopar Action magazine, June 2021.
You'll do fine with either 1" or 1-1/4" tubes but as already mentioned, pay attention to core thickness.
 
My biggest concern is i dont want to over cool the engine. Before i installed a fan clutch with a fixed fan i rarely saw over 180-185. With the clutch fan setup it stays between 190-195
 
My biggest concern is i dont want to over cool the engine. Before i installed a fan clutch with a fixed fan i rarely saw over 180-185. With the clutch fan setup it stays between 190-195


There is no such thing as “over cooling” an engine. That’s what the thermostat is for. It controls minimum operating temperature.

You are much better off with the best radiator you can fit in there and let the thermostat do what it’s designed to do rather than skimp on a radiator and fight cooling issues.

With that said, 1.25 tubes all day long and twice on Sunday. Do not skimp there. Find a way to make the rest of it fit.
 
There is no such thing as “over cooling” an engine. That’s what the thermostat is for. It controls minimum operating temperature.

You are much better off with the best radiator you can fit in there and let the thermostat do what it’s designed to do rather than skimp on a radiator and fight cooling issues.

With that said, 1.25 tubes all day long and twice on Sunday. Do not skimp there. Find a way to make the rest of it fit.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^this
I put a big alum rad. in my 406 sbc pick up , it cooled so well that it cycled on the thermostat , ''no problem'' , never gave me a problem .
I`d like to have a wider one in my barracuda even now .
 
Original Mopar radiators are brass not copper. Brass is a copper/zinc alloy.
Brass conducts heat almost 50% poorer than aluminum.

Don't beat me up. Above is from pg 55 of current Mopar Action magazine, June 2021.
You'll do fine with either 1" or 1-1/4" tubes but as already mentioned, pay attention to core thickness.

I guarantee that the radiator cores are copper... tanks may be copper/brass alloy. Copper cools better than aluminum but some aluminum radiators have a different design that may make the equal to copper/brass.

An old fashioned copper fin and plate design radiator will out cool any other radiator design regardless of the material. That's what Peterbilt used in their 379 models that I owned.

I had one of those plate radiators from a Lincoln in an early latemodel stock car and it was a chore to get that 427 up past 160 degrees in a 50 lap race.

I think an aluminum radiator in a vintage car looks out of place and most don't cool as well.
 
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So it would be wise to go with the 1.25” tubes?


Whats the main benefit of the 1.25” over the 1” tubes? Just more flow?
 
So it would be wise to go with the 1.25” tubes?


Whats the main benefit of the 1.25” over the 1” tubes? Just more flow?[/QUOTE

Yes, more flow. IMO, you are always better off with the most flow you can get and let the thermostat set the minimum operating temperature. With the correct fan you should be able to drive through hell on a hot August day and not move the needle above where the thermostat opens, or very much anyway.

Also before I forget...you want the water pump the turn faster than the crank. I’m about 6% overdriven and Id like to get to 15% over or so if I can find the pulleys.

At 6% over on 100 degree days my temp stays at 170 all day long. It goes up about 5 degrees if I get stopped by along train or a stupid long stop light. That’s as high as it ever goes.

I suspect that if I had the pump turning faster it wouldn’t gain any temperature even waiting for the railroad to hump 20 cars.
 
Yes sir. Two big cores flow more than 3 or 4 smaller ones. It’s all about flow...coolant and air flow.

It’s NOT just about flow. It’s about surface area too. If you look at the thermodynamic equations that govern heat transfer, the two biggest components are surface area and flow.

So no, you can’t just say bigger tubes and fewer rows are always better. That’s 100% not true.

It’s a balance between flow and surface area. The Champion 3 row radiator, with .75” tubes, cools my .060” over all iron 340 pushing 400+ hp just fine. And I drive it all summer in temps as high as 110* F. Giant tubes are just as much of an advertising gimmick as adding more and more rows. You don’t need (or want) a 4 row radiator, just like you probably don’t need or want a 2 row with 1.5” or bigger tubes. Anybody that says different is trying to sell you something. And probably never had any education in thermodynamics.

Between a 3 row with .75" tubes and a 2 row with 1" or 1.25" tubes the cooling numbers would come down the specific manufacturing details of that radiator. But I've seen both work just fine in an A-body, so unless you have more than the published information saying one is better than the other is just personal bias.
 
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I did notice my temps jump about 10 degrees going from a fixed fan to a clutch setup. Also running a high flow water pump and t-stat
 
I just went and looked, my factory style radiator appears to have 3 rows of tubes and they look to be 1/2”
 
It’s NOT just about flow. It’s about surface area too. If you look at the thermodynamic equations that govern heat transfer, the two biggest components are surface area and flow.

So no, you can’t just say bigger tubes and fewer rows are always better. That’s 100% not true.

It’s a balance between flow and surface area. The Champion 3 row radiator, with .75” tubes, cools my .060” over all iron 340 pushing 400+ hp just fine. And I drive it all summer in temps as high as 110* F. Giant tubes are just as much of an advertising gimmick as adding more and more rows. You don’t need (or want) a 4 row radiator, just like you probably don’t need or want a 2 row with 1.5” or bigger tubes. Anybody that says different is trying to sell you something. And probably never had any education in thermodynamics.

Between a 3 row with .75" tubes and a 2 row with 1" or 1.25" tubes the cooling numbers would come down the specific manufacturing details of that radiator. But I've seen both work just fine in an A-body, so unless you have more than the published information saying one is better than the other is just personal bias.


I’m not disagreeing. I said the 1 inch tubes are plenty for what he is doing. And yes, it’s not just about tube size. I’d take two tubes (or in the case of my truck) one big tube over 3 or 4 all day long.

It’s also important that there is turbulence to keep the coolant in contact with the tube no matter what size it is.

I’ll say it again. It pays long term dividends to fit the biggest radiator you can, run a high flow pump as fast as you can and still keep the belts on and let the thermostat do its job.

It would be educational to test and see how one or two cores compare to three or four cores compare at various flow rates.
 
Im seriously thinking of ditching the milodon water pump and going with the flowkooler paired with a emp/stewart components 180 t stat

the milodon is only 2 years old and its slowly leaking out of the weep hole only when the engine is off
 
Ok guys well i suppose its time, ran her on sunday and of course the classic industries radiator appears to be leaking at the bottom tank on the drivers side. Not dripping but enough to notice, guess its time to go aluminum. I contacted wizard cooling and they recommended to go with the 1.25” tubes over the 1” they told me anything at or over 400 hp they recommend the 1.25” tubes.

i have been using 50/50 conventional green coolant and they also recommended i use a corrosion inhibitor as well. Do i need to? Has anyone used a corrosion inhibitor?
 
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