Whether you race on dirt or asphalt, competition can be rough on parts, especially radiators. Flying rocks, chunks of dirt, bits of asphalt, and rubber can easily bend, clog, and damage the critical aluminum fins of a radiator. Not to mention the constant bumping playing havoc with mounting points, welds, and more. Your radiator is the most critical component of your cooling system, and with the summer months just around the corner now is the perfect time to do a little cooling system evaluation to make sure yours is up to snuff.
Note how the aluminum fins...
Note how the aluminum fins are folded over, bent, and damaged. No doubt the result of flying chunks of dirt, rocks, and mud. Fins bent over in this fashion cannot do the job of circulating the air.
Our Dirt Late Model project offers the perfect testbed for his story. It is a standard Saturday night racecar, 2002 Rayburn chassis, 362 open motor class Chevy. Bobby Clark, our driver and occasional freelance contributor, bought the car four years ago. The car had the radiator and cooling system in it when he bought it. Bobby has raced it at least 30 times so we know that the radiator has seen quite a bit of action. Class rules for this car dictate distilled water only, so there's nothing fancy floating around inside.
We began our process with a good inspection of the current radiator and all the hoses, couplings, and mounts. What we found could be classified as typical in the Saturday night market. The mounts looked fairly good, if not a bit worn, but the front of the radiator, as well as the housing and shroud, was pretty beaten up.
Clearly this hose is shot....
Clearly this hose is shot. The crack did not go all the way through, so the system performed fine when it raced last, but if we didn't do the inspection this crack would eventually spell disaster.
Knowing full and well that we were going to need a new radiator, we turned our attention to the hoses. Considering the age of the system we were not all that surprised to find cracks in both hoses. But even if we didn't find anything outwardly wrong with the hoses we would still advocate changing them. Hoses, particularly the push-on type that we are using, are not that expensive. So there is no reason to put old hoses on a new radiator and risk missing a brewing problem not caught by a naked eye inspection.
While we're on the subject of hoses, let's take a quick look at radiator fittings. We talked to David Bridges at C&R Racing and he said that the majority of their Dirt Late Model radiators are built with a 1 1/2 inch push-on hose fitting. "We do build special radiators for a few guys like Scott Bloomquist with a -16 AN male top hose fitting," says Bridges. "It's a cleaner and more sanitary look than using a rubber push-on hose. It's also a little safer because you eliminate the possibility of the push-on hose blowing off, the hose clamp cutting the rubber hose, and the braided line can take a little more wear and tear."
But the custom set ups for the Bloomers of the world are not necessary for the Saturday night racer. Bridges says that they build the DLM radiators with the 1 1/2 inch push-on hose in an effort to make them less expensive to build which translates into a more cost-effective product for the customer.
The housing which holds and...
The housing which holds and protects the radiator has some damage to the bottom side. The origin of how the damage got there is not important. What is important is that the hard jolt that caused it could have had an effect on the internals of the radiator. The shroud was in rough shape, too.
The purpose of this Dirt Late Model project is to rebuild a real world racecar and then race it in a regional series (The United Dirt Late Model Challenge) as well as at other tracks in and near Florida. While we will use the project to showcase and test new products from manufacturers, we are stressing the fact that this is a real world build. In other words, we will look at parts decisions from a competitive/performance angle as well as its cost-effectiveness.
That being said, we had a decision to make when it came to the radiator. A quick review of radiator tech first will help us make those decisions. First and foremost, almost all racing radiators are constructed of aluminum because aluminum efficiently transfers heat from the water flowing through it to the air outside. Of course this only happens when the water is in direct contact with the aluminum. Consequently, manufacturers maximize the cooling effect by increasing the surface area of the radiator tubing (which holds the water). Typically, these tubes are very wide from front to back but slim from top to bottom. Dozens of these slim tubes are stacked on top of one another with small air spaces left in between. As the hot water or coolant flows from the motor through these tubes it is cooled down before returning through the motor's water jacket.