Does it matter, if the over all core dimensions and tube spacing are the same, whether or not a radiator is made up of 1 row of very large tubes or several rows of smaller tubes? Would one design cool better than the other?
Here's specs for 1971... HD radiators have more fins per inch but none are single core... Only singles I've seen were on 4cyl Fox Stangs or similar other makes...
I was actually speaking of 2 radiators that were 100% identical (overall dimensions, material, fin spacing, ect)except for the core design. Everyone says "get a 4 core" but would a single core of the exact same dimension be just as good?
It all really depends on the size of the single core version, 1.25" or 1.5" wide?, but you'd need a fairly large single core to match the cooling surface area of 4 smaller cores. Yes there are more fins per sq/in in the 4 core setup but they are obviously considerably narrower than even a single core. So.. what these guys are trying to get across here is that the newer gen rad's are much more efficient in design than the older copper 4 core designs of yesteryear. Which is of course why you don't see many 4 core setups being used anymore. They're simply not needed and are much heavier than the smaller more efficient versions which are more compact and therefore lighter overall. Plus there's the simple fact that unless you have a huge big-block stroker motor in a vehicle that barley moves through the airstream?.. a typical engine in these cars.. no matter how powerful it may be rated.. will barely put out much BTU's in idle/part throttle situations to warrant such a large cooling system. To give more perspective, my Comets initial mule motor build will run around 400 horses and then be upgraded to a little over 500 hundred horse and I will only run a newer single core setup with 2 mid-sized 12" e-fans. My 500 horse 383 Blazer also used a FACTORY single core rad without issue as well.
The smaller tube diameter increases the surface area that the coolant can give up heat to. So a single row of 1 1/2" tube wouldn't be very efficient.
OTOH, smaller tubes (4 core) plug easier and the increased density impedes airflow thru the core. IMO, the material (alum over anything else) is more important...
Hot air from the first three cores won't cool the fourth core...also air will flow easier through 3 cores than 4 cores. Copper is better at transferring heat than aluminum. Copper cost more than aluminum is the reason newer cars have aluminum radiators. Aluminum tubes are thinner than copper tubes and weigh less than a copper radiator
This ^^^ Also there are diminishing returns in the smaller tubes, eventually having enough air flow through the small space becomes a problem, also already mentioned they can clog more easily... The chart lists a smaller & thicker radiator for 302(I believe three core), sometime in mid '72 it was replaced with a similar radiator listed for the 250, AFAIK the early radiator isn't currently reproduced...
The math isn't that hard to do. 2 x .75" cores don;t have much more surface area than a 1 x 1.5" core. Plus, as mentioned already several times, air flow through the wider/thicker cooling fins will become more efficient. It's certainly true that copper is better at transmitting heat than AL but the difference between the two for the temps we are discussing here is nothing phenominal and the weight difference between the two is considerable. Especially when comparing a 2 x 1" core AL setup to a 4 core copper setup. And that unnecessarily added weight is at the worst possible location you could put it on our cars. Look at all the serious race car stuff and you'll see that they rarely use 4 cores of copper because weight is a major concern and copper x 4 is not neccessary even at elevated power levels. And I'll make the point again.. unless you're building a big-block powered Maverick cop car that sits along side the roadway at idle with the AC blasting while your issuing tickets to us Comet owners?.. this is all just unnecessarily added weight and major overkill on the cooling side of things. And believe you me.. overkill is my middle name in just about everything I build or redesign. The typical motors we run are small(peak horsepower is irrelevant since that only happens when we are not sitting still) and the cars are generally moving through the air enough to allow a little single core rad to do the job quite well. IMHO, if you're really that into cooling efficiency then you should be looking into twin 1.25" - 1.5" core double pass rad designs with ultra high fin counts(more $$$) and thermostatically controlled e-fans(more $$$) combined with a water wetter/surface temperature reducing chemicals and lower temp t-stat. With all of the above combined in one compact and lightweight package.. you can cool just about any conceivable engine combo out there regardless of engine size and/or power output capability. I've easily done it several times with only part of that combo and the OEM's have been doing it for years. Not to mention that not everyone running supercharged or twin-turbo LS and MOD motors runs out to buy an old style 4 core copper setups. Efficiency of design and properly shrouded/directed airflow is key.
I've had hotrods back before aluminum radiators were mainstream, when all you could get for reasonable cost was brass. Every single one was an overheating nightmare to drive more than a few miles. Spent lots of $$$ on more cores, special coatings, bigger fans, etc. When I switched over to aluminum, all that stopped. Not to be trite, but "been there done that", and it won't ever happen again...
yep.. and many of those extra tiny little cores clogged up almost immediately if there was any junk or sludge at all left in the cooling system. The rad shops really loved all those "last ditch effort" engine flushes and silicone too.. made them tons of extra cash to rod all that freshly kicked up trash out of their newly built "4 core" work.
The last sentence really sums it up. I've witnessed a number of Mavericks that owners claim are running hot, only to observe the absence of a fan shroud.
I am not addressing a real overheating problem, but I added a wetting agent to my coolant and my Maverick runs 15 degrees cooler than before. I am running a 160 degree thermostat and my car runs about 100 degrees over the ambient temperature.
Yep, no shroud means the fan is mostly pulling from around the back side or radiator, not through it... Plus a thicker radiator generally only worsens the problem, as it's more difficult to pull air through them...
