Wrecked82

Just my comment, my seals disappeared a few radiator replacements ago (245K miles). Had an aluminum (Champion) radiator installed a year ago. No seals. Stays under 200* in HOT Houston weather.

jb78L-82

I have to agree...My 78 L-82 has the OEM radiator seals or what is left of them and the engine runs 175-180 no matter what the weather..the seals do NOT seem to matter much with an aluminum radiator. The chin spoiler and extended air dam spoiler on my 78 L-82 are MUCh more important. I think the seals matter more if you use a marginal brass/cooper radiator since the cooling capacity is much less than aluminum....

The13Bats

I see all kinds of things posted for why c3s overheat and many are true,
However, not cut in stone,

The seals are most important on a stock c3 with old radiator made worse in hotter climates with ac, etc etc,

In a case of a stock c3 cooling system which when new worked, but some did if taxed creeped up, others didnt, perhaps that is marginal.

In my case my dewitts is overkill, my fans not dewitts, better more cfm are overkill,
My car will be far more forgiving, seals, hood off, ac, etc its not gonna overheat,

Guys who buy oversized radiators regardless of brand will see this too,
Heck, guys with a good factory radiator especially 4 row will see great cooling,

overlooked is its not the price one pays for their radiator or brand that makes it cool well its the one you choose,
Cragar and american racing both are wheels,

And many guys are doing great with $200 plus minus radiators,

yeah, i wish i had thought about it longer before buying,

Ps,
Aluminum does not shed heat better than bc radiators, aluminum is lighter and many years ago bc had weld bloom issues aluminum doesnt have,
Bc same size will cool as good or likely better than aluminum....

PainfullySlow

People on this forum seem to love to spread whatever information that they have heard in the past and treat it as gospel.

Don't guess, know.

http://www.cgj.com/2013/07/16/alumin...inal-thoughts/

Aluminum makes for a vastly superior radiator due to material strength and design considerations. This is not open to debate.

The only reason to stay with copper/brass is if you are going for originality. From a functional or cost standpoint, there isn't a comparison.

0Tom@Dewitt

SO TRUE!!!! 100% Agree.

Good find on the CG&J article. Phillip is a friend of mine and another brazer of aluminum. We buy product from each other from time to time.

I find that 99% of CF members will not leave the forum (click on links) that provide the information they need. Don't know why...it's just the way it is. They can ask a question, you post a link to the answer, and then they will ask the question again or take the advice from someone in the field of dentistry or a lawyer. Nothing against these professions but I would never tell someone how to fix a cavity.

If you realy what to know aluminum WORKS better, CLICK HERE, for a real simple explanation.

Big2Bird

Nope:

Which metals conduct heat best
Common metals ranked by thermal conductivity
Rank Metal Thermal Conductivity [BTU/(hr·ft⋅°F)]
1 Copper 223
2 Aluminum 118
3 Brass 64
4 Steel 17
5 Bronze 15

jb78L-82

From Dewitt's website:

Copper is actually a better conductor of heat than aluminum. The problem is a copper radiator is not ALL copper. The tubes and fin are copper however they are bonded together with lead, which has horrible heat transfer capabilities. The end tanks are brass and the side channels are steel. The trick to better cooling is wider tubes and shorter fin. This increases the “tube to fin” contact area, which determines the radiator efficiency.

A typical 4 row copper radiator uses 7/16" tubes while the aluminum radiators use two rows 1" tubes.




Then the copper radiator uses 1/2 tall fin while the aluminum radiator uses 3/8" fin. The shorter fin increases the number of tube layers in a given stack up. For example a 18.5" tall radiator has 30 layers for the copper unit versus 40 layers for the aluminum. So you have more layers per stack up and more surface area in each layer. The aluminum radiator is 100% aluminum, furnace brazed. 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.

PainfullySlow

Not to mention copper radiators are coated, further reducing thermal efficiency while aluminum is left au natural.

It is not a question of which metal conducts heat better. All things being equal, copper easily beats aluminum however things are NOT equal. It isn't a question of which metal is better, it is which makes a better RADIATOR. Hands down, there is no question. Sorry to burst your bubble.

Finally, since Tom mentioned above people tend to not like to bother with actual facts, let me toss this out: If copper is so amazing for radiators, why aren't they running copper in NASCAR? F1? Pretty much any performance machine anywhere?

I thought so.

69427

I agree with your post, but not necessarily your attitude.

I expect the answer to your question is while copper is approximately twice as efficient as aluminum in heat transfer, copper/brass is also about three times heavier than aluminum for the same volume.

Road hugging weight is no longer something to advertise/market.

69427

OP: Are you sure your low speed timing curve (including a working vacuum advance) is set/operating correctly?

0Tom@Dewitt

First, welcome to the CF. There is a huge amount of information here and it can be very beneficial but there is also a lot to learn about using this media. You will see excellent advice and some not so good advice. Some members will not read or listen close enough and just randomly post a response. Typically what they did to solve a problem, even when it's a different application (year/model). so be careful.

In this thread, you have a bunch of help with a problem you failed to identify. It's very common to be worried about coolant temperatures and "wanting" it to run cooler, but that doesn't make it a problem. Truth be told, the best thing GM ever did for me was install gauges in these cars. If they had the old idiot lights I would have sold about 1/2 the radiators I did.

I'd like to create a new CF acronym for all to use.

BSGM

A BSGM is, to steal gospel from another member, is a Bull $hit Gospel Myth. This one of those things that everyone believes, quotes, and accepts as fact despite having any real proof or experience in that area.

My#1 BSGM is ...
"Corvettes ran hot from the factory." "Or Corvettes always had cooling problems" The truth is they did not. No dealer handed a customer keys and said "oh, don't drive when it's hot outside". Now I am not talking about rare special race cars with no factory shroud and stuff. Standard issue Corvettes ran just like all other cars.

High on my list, let's say BSGM #2 is ....
Cooler is better, and 200 is way too hot.

Not true either. I could substitute Gospel with Gut because often I feel people have these "Gut" feeling something is true and they must address it, even when they don't know for sure it's true. The Gut says it is, so it must be.

The truth is, engines to not get uncomfortable, drivers do. Humans have a problem when the ambient air varies 10-15 degrees. If your body temperature goes up as little as 5 degrees you could die. There is little to no effect on the engine to run anywhere between 180-220 coolant temperatures. How do I know this? GM engineers told me so but let me give you some buck up support. All Corvettes designed after 1984 are designed by the factory to run at 230. Some do not kick on the fans until 235. Back in the 70's I drove Chevelles and Impala's that had idiot lights. These didn't trigger a warning until 230 degrees, and when they turned off it gave you the feeling everything was normal, even though the temperature only dropped to 210. I put 150,000 miles on a car that had the engine light come on and off with no issues at all. If I had a temperature gauge I would have probably been freaking out.

Bottom line, relax! Don't chase a problem you don't have or "feel" needs fixing. Buy an IR gun and confirm your gauge is giving you accurate information. 200 degrees on a warm summer day won't hurt anything. If it get's hotter than that, and its accurate, you might want to figure out what's not working right.

0Tom@Dewitt

Our lab tests showed painting a radiator had no effect on cooling.
I have to throw the BSGM flag on that one. Don't be offended, hundreds of people think painting ruins a radiator.

69427

I agree. I've got one of your black painted aluminum radiators in my '69 (and a 195* thermostat). I've yet to have any overheating issues, even on 90+ degree track days.

The13Bats

Attitudes on the forum....never

People here have various agendas, some perch ready to jump not adding just trying to chop someone up, burst their bubble as some put it,
More power to them.

I see things people, i have had it happen to me post and they are misunderstood, taken out of context, sometimes even have what they say revamped, its how forums are,

My remark about aluminum and bc is summed up far better below copied from another members post so im not the only one who believes this, i never said it was practical, even though many members do use bc and their cars cool just fine, okay, they do weigh a bit less than 90 pounds,

I thought everyone knew racers pick parts with weight playing a big role in that,
A 90 pound radiator isnt gonna float any gear head knows that...

Have a good one guys,

The13Bats

Is special radiator paint required?
I would like black better,

69427

I don't know what "formula" paint Tom uses on his radiators, hopefully he'll chime in. My purely uneducated opinion is that regardless of what it is, the thermal path through the paint is so short that the net thermal impedance has gotta be darn small.

I requested mine in black paint as I like the stock look, but not the stock weight.

0Tom@Dewitt

We use a two part epoxy paint that we had made for us with a gloss point that makes gm black enamel used on suspension parts. No too shiney and not flat.

Paint does not change a radiator's ability to transfer heat, and no paint or coating can improve it. I have heard some very smart people (even friends of mine) say they think painting is bad and will hold in heat. When I ask how they know this they say...ahh, doesn't it?

resdoggie

I read long ago that paint colours do affect heating/cooling characteristics but to what extent? Black paint will radiate heat (away from the radiator to improve cooling) better than white paint. Ever see a radiator painted white? Why paint a rad in the first place? BC doesn't rust so painting isn't for rust prevention. To some it would look better and the factory did paint them - black, no other colour but. Engine blocks are sometimes painted black. It radiates heat better or it looks better? Maybe a bit of both. As Tom mentions about painting a rad or not, his results showed no difference. But the question remains, why black paint?

PainfullySlow

True enough, and I apologize if that came across harsh. One of my biggest forum peeves (on any forum, not just this one) is the regurgitation of incorrect information. I tend to be a zealot about it and it got the better of me.

In addition to weight, it is my understanding that copper is a relatively weak metal when compared to aluminum and that designers are able to make a more efficient radiator core out of the stronger metal (larger tubes > more surface area > better cooling). I read this someplace, do not take as gospel as it is not an accredited source.

No worries, I do not get offended and if I am guilty of spreading misinformation then I appreciate you calling me out.

I would be very interested in your findings as this intrigues me. As far as I know there is no coating that has perfect thermal efficiency which means that any coating, unless the material has a higher heat exchange rate than the base material (copper in this case) it will serve as an insulator and reduce efficiency. It may be so minute that it is irrelevant for this application and not affect cooling by a measurable amount.

My own experience has always been that a coating reduces heat transfer so I hope that I have not been guilty of the exact same thing that I really despise: spreading misinformation.

One other thing that I had not considered is that by applying a coating you are effectively increasing the surface area of the cooling material which would increase thermal exchange. If the increase in surface area were enough to offset the reduction in the coating material they could effectively cancel one another out. I am now going to have to do some research unless you already know the answer to this. Sorry, I am one of those people that needs to know the "why" of things. I don't take anything as truth without data to back it up.

I too would love to know this and it looks like it was partially answered below.

Again, very interesting. Out of curiosity is there anything out of the ordinary that you include in this paint to increase heat exchange? Without divulging trade secrets of course. As above, it is my understanding that any coating that is not infused with a material specifically to increase thermal exchange will act as an insulator.

As an example, it is why we infuse ceramic particles into paint to coat our exhausts because ceramic increases the insulating properties of the paint, effectively reducing the amount of heat transferred out of the exhaust.

I know that there are some materials that increase thermal efficency; diamond comes to mind however I highly doubt that you are coating your radiators with diamond dust

A quick search on a reputable physics site reports that graphene (a similar carbon based material to graphite) and something I had never heard of: cubic boron arsenide (a chemical composition of boron and arsenic) have thermal exchange rates very close to that of diamond.

I am guessing the latter would be prohibitively expensive however graphite is common enough and has a higher thermal exchange rate than aluminum or even copper so in theory, coating a radiator with graphite would increase its efficiency.

Now for the sake of academia (and because my brain does not shut off) I am curious if a graphite (or similar coating that increases heat transfer) copper radiator would put it on par with a bare aluminum one...and in theory an aluminum radiator coated this way would be the most efficient of the bunch.

My sources: It is here if anyone cares to look: https://phys.org/news/2013-07-compet...conductor.html

and here is a paper on the thermal properties of graphene/graphite. It is written for use in computer chips however the thermal properties of the material remain the same: https://www.researchgate.net/profile...c-Circuits.pdf

In closing, I would like to apologize to any that I have offended with my admittedly harsh comments. Bats, 427, etc. It was not my intention to offend. It is no excuse but I have been, well, angry lately. I try not to let it affect my online presence but apparently I suck at self control lately. I will try to be more civil in the future.

Big2Bird

For the early years, radiators were exposed or right behind the grill. Black makes it disappear.
There has never been a reason to change.