Best Replacement Radiators

[cwilkie]

I am in need of a replacement radiator for my 1972 ¾ ton 4x4. The truck has a big block 427 in it with a th400 that uses the radiator to cool the transmission lines. Who makes the best radiators? I had the radiator rebuilt two years ago but I figure since it is 42 years old I should buy a new one. I use the truck to haul wood, bobcat trailer, and push snow so it needs to cool really well. I have not switched to electronic fans since it cooled fine with the mechanical fan. Just looking for advice because I want to make a purchase by Tuesday at the latest.

As always, thanks for the advice guys.

[wesmigletz]

I've used these in the past. No problems with a small block in L.A. traffic. Not sure how it would be with a BBC. I prefer factory shroud and clutch fan.

http://www.oreillyauto.com/site/c/de...yword=radiator

[Sean1985]

BeCool makes a quality radiator. They make ones for our trucks with the trans lines. Can get it with electric fans or not. We had one in a buddies 68 charger with about 600hp and we could drive it to the track and back. 4 hour round trip and never overheated.

[Fitz]

Originally Posted by Sean1985

BeCool makes a quality radiator. They make ones for our trucks with the trans lines. Can get it with electric fans or not. We had one in a buddies 68 charger with about 600hp and we could drive it to the track and back. 4 hour round trip and never overheated.

I'll second that! My 67 uses a BeCool 4 row with the electric fans (the motor is just too big for a belt driven fan) and after 6 summers here in the Desert when temps get to 110 and higher I've NEVER overheated.

[TobyArnot]

I just installed a new copper/brass radiator with my new Crate (SBC). motor. Bought it from O'Reilly's for under $200 delivered to my door. I am not a big fan of aluminum radiators. I have had some strange issues [dissimilar metal] with several brands of aluminum rads., and I just felt better going back to copper/brass. The O'Reilly rad. fit like a glove and works great. It has a trans cooler, and I added a seperate Derale cooler for my new O/D. To each his own. Just my $2 worth!

[Daddy Brim]

Originally Posted by wesmigletz

I've used these in the past. No problems with a small block in L.A. traffic. Not sure how it would be with a BBC. I prefer factory shroud and clutch fan.

http://www.oreillyauto.com/site/c/de...yword=radiator

I got mine from O'reillys also, that 4 core should be good enough for a big block. Also it will come with a lifetime guarantee, so if any thing goes wrong with it just take it back.

[Z10]

Might want to rethink the 3 or 4 core radiators. I found this write up helpful when I was selecting mine.

Enjoy:
There is considerable misinformation regarding what makes a radiator transfer heat (so take what you read with a grain of salt).

Ill try to make a short radiator and heat transfer for dummies post

Heat is transferred from the coolant to the radiator mass, and from the radiator mass to the airflow. The temperature difference at each transfer junction (coolant to metal, and metal to air) drives the quantity of heat transferred.

Aluminum weighs less, and the lower mass allows it to transfer heat more quickly than brass. The steady state heat transfer between the two materials (aluminum and brass) is very similar, but aluminum reacts quicker to a change in the temperature difference of the coolant fluid (like when you are on the throttle) because the heat transfer takes less time heating up the mass of the radiator itself before establishing the temperature difference between the radiator and the airflow. The fact the aluminum experiences an elevated surface temperature quicker allows it to reject the heat into the airflow quicker.

When the radiator is underdesigned (to reduce weight or fit a poor location) this rapid thermal response provided by aluminum can make a difference in overheating (or not) after a brief period of WFO travel (like in racing). When the load is steady state (a fixed industrial engine or a long crawl up a grade towing), the response time benefit is insignificant because while the brass takes longer to respond, having the proper area for heat transfer is more important (both radiators eventually reach the same steady state temperatures and the same heat transfer rate).

Sizing the face area of a radiator core to have one square inch for every cubic inch of displacement has been around for a long time (400 ci. engine matched to a 20"x20" radiator). This rule of thumb does not work everywhere (dry deserts need more face area) so some add 10% or more extra face area.

Core thickness is an airflow restriction on the air side (bad for heat transfer), and more tubes (one tube per core) increases surface area (good for heat transfer) on the coolant side. Multicore radiators are great for getting the radiator metal hot, but not always great for getting that extra heat into the air, and the hot air away from the radiator.

The coolant to metal transfer is fairly efficient, because both materials (coolant and metal) have significant mass to store the heat being transferred. The heat transfer junction, the required wetted area of the tubes inside the radiator core, can be calculated with fairly good accuracy. The surface area can be accomplished with more small oval tubes (1/2" and 5/8" typical of brass radiators) or with fewer larger tubes (typical aluminum 1" and 1 1/4" tubes). Go with the most tubes (cores) for the greater surface area, if the fan drive can handle the airflow restriction.

The aluminum radiator core manufacturers already take any credit for the more rapid thermal response of aluminum when calculating the tube surface area, they use the minimum surface area they can design, so further reducing the face area of the core (to try and squeeze even more efficiency from the aluminum construction) is risky unless the design can be tested and adjusted (if the budget allows doitagain engineering). I advise against reducing the face area of the core, and any thinking that the material choice allows a discount factor to the heat transfer potential, unless you are racing to shave weight and the load is transient.

The coolant side of each core tube sees the same temperature coolant flow and the same rate of heat transfer from the coolant to the radiator core metal. The result is the radiator metal is almost always the same temperature with minimal gradient front to back. The coolant to metal heat transfer is the same for each core (what heats the radiator metal is the same), and the coolant temperature leaving each core (to be delivered to the engine) is nearly the same, but the air side of the radiator is not so simple.

The discount factor for heat transfer on subsequent cores is only on the airflow side. The face cores experience unheated air, and subsequent cores experience air at a higher temperature.

The best heat transfer occurs where the greatest difference between the air temperature and the radiator metal is found, the face or entering side of the radiator. If you want the best heat transfer, increasing the face area of the radiator metal that sees cool air will gain you the most impact for your effort (a larger radiator face will beat more cores nearly every time).

The construction of the radiator fin design is important to the increase in temperature through subsequent cores in series, and is related to a "bypass factor" that models how much air bypasses heat transfer from direct contact to the surface area of the fins. The mass of air that can squeeze between (bypass) the fins without picking up heat mixes with the mass of heated air that does make contact, and the result raises the air temperature of the downstream cores.

In reality, without getting into math or fin designs, the elevation of air temperature between cores is less than 15%. If the airflow temperature is raised from 70dF to 170dF through a four core radiator, a 100 degree increase, 45 degrees (~45%) of the temperature rise (and heat transfer) is in the air to metal contact in the first core, and a lower percent from subsequent cores (something like ~30%/17%/8%).

The aluminum radiator guy's are right that two cores are more efficient (nearly 80% of the cooling is from the two front cores), but if the total surface area of the coolant to metal, and metal to air, contact is less ... the net result is not so great of a design (just like ricers 100 ci 4-banger @ 3 hp/ci is good, but nothing like a 302 @ 1 hp/ci: there is no substitute for more surface area in a radiator unless you want to spend a lot).

The actual area of the core face that experiences the high air to metal temperature difference is more important than the calculated face area. People tend to forget that the radiator face is not working to transfer heat, unless it's moving air.

What makes air flow through a radiator core (through a restriction)? Pressure drop (static pressure) or the momentum of the air mass (velocity pressure) through the core establishes the airflow, and the resulting heat transfer.

Most people with a cooling problem try to increase the mass of air blowing through the radiator by increasing the velocity pressure acting on the core. They add a round fan (usually electric) in front of the radiator (a pusher fan).

When an unshrouded fan is used, a puller with no shroud or a pusher, the core area experiencing the airflow (and temperature difference) is limited to only that is the direct path of the high velocity air. A 20x20 (400 sq.in.) radiator face with a 16" diameter fan blade, without a shroud, is little better at heat transfer than a radiator with a 16" round (201 sq.in.) face area.

Adding a 16" pusher in front of this radiator, with the unshrouded 16" puller, gains almost nothing in air side heat transfer effect.

How do you get the entire entering face of the radiator to work transfering heat? You try to get airflow across the entire face of the radiator core.

Try many small fans (fit lots of round high velocity airstreams in a square area)? It can work, but it's looks complicated (and is probably expensive).

It's easier to make a static pressure difference across the radiator core work to move air through the entire face of the radiator, by using a puller fan and fitting a shroud on the suction side of the core. You only need one fan, and it can motivate airflow across the entire face area of the radiator core, just by adding a shroud to contain an area of negative pressure on the leaving air side of the core.

The problem with using static pressure to draw airflow through a radiator is that it takes a significant increase in power to generate pressure (research fan laws). Using a multicore radiator core that is thick and restrictive on the air side requires that it be matched with a fan and shroud that can generate a static pressure difference great enough to overcome the restriction.

Replacing a two core with a more airflow restrictive four core can sometimes work against you if the fan clutch is weak, or it is combined with a swap to an electric fan.

Most electric fans cannot develop significant airflow at higher static pressures, because the power draw must be limited to protect the wiring. Compare an electric fan to a high flow (and pressure) mechanical fan. The blades of the electric are narrow, and the blade pitch is shallow (compared to the mechanical fan), both design aspects limit the potential of an over-amp condition. Yes, electric fans are great to gain power on the end of the crankshaft, because to generate a significant negative pressure behind the radiator sometimes takes three to five horsepower (the gains we read in the electric fan advertisements). Use electric fans when you can, when the radiator is overdesigned for the power and transient heat transfer required, and use a shroud. Just do not expect a 1/4 hp electric to pull the same airflow and pressure drop of a fan drawing 3 hp off the front of the engine.

I read that fans have little effect to gain airflow at speed ("airflow is going through the radiator on the highway because you are going faster, so adding a fan or shroud to cool the engine on the highway is not going to solve the problem.") We read it all the time. It's BS.

What is difficult to understand is that most vehicles generate a high pressure area under the chassis at speed (the air above and to the sides of the vehicle is high velocity/low pressure, but underneath it's low velocity and high pressure). Yes, the pressure in front of the radiator can be higher (conversion of the velocity pressure to static pressure) but the pressure behind the radiator can increase with speed as well. Betting that the converted high velocity air in front of the vehicle radiator can overcome the pressure under the vehicle (the pressure on the leaving side of most unaided radiator cores), to motivate airflow, is almost like betting that you can piss up the inside of the airhose of your compressor with 20 psi streaming out the end.

You still need a fan and shroud to eliminate most radiator airflow problems at highway speeds, because you still need to establish a pressure drop across the radiator core (and sometimes it's more difficult at 60 mph, than when parked at the curb).

Crossflow vs. downflow design is not as important as where the radiator cap pressure relief is located. The cap should be on the low pressure side of the water pump, something that is easier to package and service with a crossflow core.

I hope this helps (I have had enough internet tech for the week)?

In summary: if the budget demands a choice between a high dollar aluminum radiator, or a brass radiator and a well fitting shroud, get the system with the shroud (and use a mechanical fan drive with a fan blade that has some pitch angle to the blades, and a clutch to save power when it's not needed).

Happy Trails!

[cwilkie]

A Bee Cool radiator would be nice but I am needing something in the price range of $300 or less. Anyone ever buy one from NAPA?

Ever here of this one from Engineered Cooling Products for $239?
http://www.speedcooling.com/1967-197...r/prod_38.html

[cwilkie]

That is a very good point. I am looking for something that is a direct fit and will cool my big block with a mechanical fan with no issues. Is there something wrong with using an aluminum radiator?

[TobyArnot]

Not really anything "wrong" with aluminum rads., other than the initial cost of a good one. But, if you decide to use one, I suggest going to a local Marine Supply house and purchasing a "disposable sacrificial anode", which is a fancy name for a lead sinker attached to a ring under the radiator cap with a short piece of chain. The lead will slowly dissolve due to galvanic corrosion and will help keep the aluminum "healthy" for a much longer time.

[Z10]

I'm using one of these: http://www.speedcooling.com/coretypes/info_6.html
behind my 375hp small block with absolutely no issues and it's a direct fit that looks more like the originals. Also some good info on core design.

[LSUMurse]

I got one from Autozone for less than $200. I could never find out if it's a 4 row or 3 row, but I had to get 4 row radiator brackets to hold it. I have had zero problems with it thus far.

http://www.autozone.com/autozone/par...7011_266534_0_

[9teen69]

Originally Posted by Z10

I'm using one of these: http://www.speedcooling.com/coretypes/info_6.html
behind my 375hp small block with absolutely no issues and it's a direct fit that looks more like the originals. Also some good info on core design.

Got the same radiator, close to stock look. I was going to paint black but it looks too good. $240

[Hugh Mongus]

I bought an Ebay special when I installed my new engine. It was easy to install and it works great. All aluminum for $172

http://www.ebay.com/itm/3-Rows-1967-...item51aef2599c

[skorpioskorpio]

Originally Posted by TobyArnot

Not really anything "wrong" with aluminum rads., other than the initial cost of a good one. But, if you decide to use one, I suggest going to a local Marine Supply house and purchasing a "disposable sacrificial anode", which is a fancy name for a lead sinker attached to a ring under the radiator cap with a short piece of chain. The lead will slowly dissolve due to galvanic corrosion and will help keep the aluminum "healthy" for a much longer time.

Actually marine sacrificial anodes are zinc not lead, there is also magnesium ones that are used in hot water heaters. Though I think marine sacraficial anodes are specifically intended to reverse electrolosis electron flow to prevent iron corrosion, I don't know if it helps aluminum.

[POPO1984]

I have a Vista pro 4 row. Summit sales them

[cwilkie]

I purchased a Murray 433369 and it did not have an inlet for the heater core return line. I am bringing it back for a Murray 433366. Does anyone know if that has the heater core return hose? My only other option locally is a spectra brand. I wish I had the funds for a be cool radiator but that is not happening anytime soon.

I need one like the picture below.

[Lee H]

The radiator from your local auto parts house will cool your motor just fine, and as you already know returns are painless if there is a problem, and your supporting your community. If your water pump has a plug on the top you can return your heater hose there.

[67 cst swb]

My Opinion...
If a quality radiators shop rebuilt your OE (40+ year old) radiator with a new core 2 years ago. Then it should be good for many more years.
What did the radiator do to "rebuild" your stock radiator?
The metals that were available 40+ years ago is much better and probably thicker than the metals you would get in a new copper/brass radiator today.

[Hawghauler]

Originally Posted by 67 cst swb

My Opinion...
If a quality radiators shop rebuilt your OE (40+ year old) radiator with a new core 2 years ago. Then it should be good for many more years.
What did the radiator do to "rebuild" you stock radiator?
The metals that were available 40+ years ago is much better and probably thicker than the metals you would get in a new copper/brass radiator today.

I agree. If you had it rebuilt, the only original parts left are the chambers on the ends. The core was most likely completely replaced. The end reservoirs are going to be better quality than a new one where money savings for the maker is more important than customer happiness. I'd just leave it alone.

[alsriv2]

Z10, that is a well presented write up on engine cooling.
I will be completing an installation of a 396BB, 469HP, very soon in my C10 and was concerned about cooling methods in the hot Phoenix climate.

Now all I need to do is purchase a new clutch and BB fan assembly for my setup (I have the original shroud) and hopefully I will be good to go.

[Z10]

Originally Posted by alsriv2

Z10, that is a well presented write up on engine cooling.
I will be completing an installation of a 396BB, 469HP, very soon in my C10 and was concerned about cooling methods in the hot Phoenix climate.

Now all I need to do is purchase a new clutch and BB fan assembly for my setup (I have the original shroud) and hopefully I will be good to go.

Al, I live in W.Texas and our heat is similar to Tucson, so a little cooler than yours. I'm using a 2 core from http://www.speedcooling.com/1967-197...r/prod_38.html which is less than $250 and looks a lot like a factory rad.
I'm using this behind a pretty healthy ZZ4 small block pushing around 375hp. With the A/C on and driving 80, the temp is a rock solid 180-190 no matter what the outside temp is. I think the other big factor is using a good shroud. Mine was custom built and is using 2 electric fans that I sourced from a 2003 Pontiac Grand Am V6. Rarely does the second fan switch on.
Good luck on your cooling quest.

[slow-1]

This one should do it.

http://67-72chevytrucks.com/vboard/s...d.php?t=589010

[scrappydoo2k2]

Originally Posted by Z10

Al, I live in W.Texas and our heat is similar to Tucson, so a little cooler than yours. I'm using a 2 core from http://www.speedcooling.com/1967-197...r/prod_38.html which is less than $250 and looks a lot like a factory rad.
I'm using this behind a pretty healthy ZZ4 small block pushing around 375hp. With the A/C on and driving 80, the temp is a rock solid 180-190 no matter what the outside temp is. I think the other big factor is using a good shroud. Mine was custom built and is using 2 electric fans that I sourced from a 2003 Pontiac Grand Am V6. Rarely does the second fan switch on.
Good luck on your cooling quest.

Hey Z10, Were your able to use your stock upper retaining brackets for the aluminum radiator you got (http://www.speedcooling.com/1967-197...prod_38.html)? In other words, does it use the 3-core or the 4-core upper retaining bracket? I ordered one and want to make sure I can install quickly when it arrives (and I need to get another retaining bracket since I lost one during my engine rebuilt project).

Thanks,
Robert

[Z10]

Originally Posted by scrappydoo2k2

Hey Z10, Were your able to use your stock upper retaining brackets for the aluminum radiator you got (http://www.speedcooling.com/1967-197...prod_38.html)? In other words, does it use the 3-core or the 4-core upper retaining bracket? I ordered one and want to make sure I can install quickly when it arrives (and I need to get another retaining bracket since I lost one during my engine rebuilt project).

Thanks,
Robert

Hi Robert, yes the factory style brackets should work for you. Here are a couple of pics of mine.