Bulletproof cooling system

*Oftentimes, the cheapest and most bulletproof way is to use the largest radiator that will fit, along with the shroud that was designed for the radiator from the factory and the designated steel fan and viscous drive assembly for same. ''(confirm and expand)''

*Use a full shroud, with the radiator positioned so that the fan blades are half-in and half-out of the shroud hole ''(confirm and expand)'', and no more than 1" of clearance between the shroud and the fan blade tips. (Just enough to prevent interference when the motor rocks on its rubber mounts).

*Fan recommendations: OEM 18 inch, 7-blade steel fan with 2" to 2-3/4" pitch. Pitch of a fan can be measured by laying the fan down on a flat surface and measuring from the flat surface to the edge of the fan blade. Fans that are relatively flat (such as a flex fan) won't move enough air at idle and low engine RPM to do the job properly.  

*Water pump and crankshaft pulleys sized according to what was on the engine from the factory. On a street motor, shoot for 1.2 to 1.3 times crank speed for pump pulley speed. This is usually true until you get to 3.55 gears and numerically higher, then 1 to 1 works better. Most 1960's muscle cars are 1 to 1. Sustained pump speeds over 4200 rpm can cause cavitation. Race vehicles may use a 3.5" crank pulley with a 8" water pump pulley for a 9000-plus rpm engine.

*On a carburetor-equipped engine, most of us use a 180º thermostat, although a little hotter thermostat (190º-195º) may make the motor more responsive and add a little fuel mileage. It may also help to burn off some of the by-products of operation, such as moisture and acids which form and get into the oil. Motors using EFI induction should be operated at the temperature specified by the factory for that particular motor to prevent false input to the computer and consequent problems. ''(confirm and expand)'' The sensor pill goes toward the motor.

*Ensure that there are sufficient openings in the engine compartment to allow the exit of all the air drawn into the compartment. This might require the removal or surgery of inner fender panels or using spacers to raise the hood of the car up an inch or two at the back.

*Before installing the water pump, grasp the impeller with one hand and the drive hub with the other and twist to make sure the impeller is tight on the drive shaft. Not finding this problem beforehand can make you crazy.

*Although it may not be necessary, the concept of a "water pump conversion disc" is intriguing. Flow Kooler originally marketed flat aluminum discs to rivet to the backside of the stamped steel impeller in the pump. With an iron impeller, a steel disc could be welded or brazed onto the impeller. The disc wouldn't be that difficult to make. Space the water pump backing plate back farther with a couple of gaskets to prevent interference of the rivet heads on the backing plate if riveting a disc to a stamped steel impeller. More info: [http://www.smokstak.com/forum/showthread.php?t=11774 brazing cast iron], [http://store.summitracing.com/partdetail.asp?part=BRA%2D4375%2D07&autoview=sku Flow Kooler water pump conversion discs]. This disc should make an appreciable difference in the flow of water at engine speeds under 3,000 RPM. On the other hand, Howard Stewart of Stewart Components (the guy with the water pump dyno), says that the disc's have little to no effect.

'''NOTE:''' While a thermostatically modulated fan clutch is an effective means of operating the cooling system's fan, a worn or defective fan clutch can cause overheating yet go undiagnosed. Sometimes they will appear to be OK when cold but they will free-wheel when hot!

===Cadillac radiator swap===

Any of the Fleetwood or Eldorado Caddy’s from '70 to '76 with a 472 or 500 will work, but the '76 used the 500 inch motor for sure.

Now, you will have a radiator that will cool anything and you still have the stock attachment of the  stubs to the recipient vehicle so you can use simple hand tools to disassemble the whole mess later if you have to. It'll all come out as one piece  -- because it is one piece.

Moving the air through the radiator is one of the most important points of engine cooling and heat dispersal. In order for cooling to take place, the air MUST move through the radiator fins, and, by way of convection, the cooler air will remove the heat from the engine coolant to the outside air flow. For this to happen, the frontal area of the vehicle must be clear and the entering air must not be blocked. The radiator fins must be clean, clear and unblocked by mechanical damage, i.e. folded over fins, plugged by bugs and dirt. The air must pass THROUGH the radiator, NOT OVER OR AROUND IT. Seal up hood-to-radiator cradle air spaces with sheet metal or rubber sheeting. The fan shroud should contain at least 90% of the fan blade circumferentially and the edges should be sealed to the contours of the radiator for maximum suction by the fan.  Hot exhausted air should have an escape route out of the engine compartment. If it doesn't, make louvers or outside air scoops. Direct air to pass over the engine and exhaust manifolds or headers, then out the bottom and sides away from the passenger compartment. Don't remove the rubber skirts from the inner wheel wells over the suspension, they are there for a reason. The reason is, air flow is smoothed over the A-arms and is not turbulent or 'ragged' so it will flow out of the engine compartment faster. The rubber skirt also keeps road grime, stones and debris from entering the engine compartment and radiator area.

If you have an external transmission cooler in front of the radiator and also have a high stall torque converter, the fluid temperature in the transmission cooler will pre-heat the incoming air to the radiator. If this is the case, try relocating the transmission  cooler to another location. Remember when doing this though, that if the car isn't moving, there is no cooling air going over the cooler to bring fluid temperatures down.

Hood removal will cause buffeting of air in the engine compartment and result in uneven pressure. Removal of side panels on three piece hoods will exhaust air better in some cases. Louvers in hoods and side panels are a godsend to ventilating hot air from the engine compartment. Fade-away fenders of the 30 's and 40's remove a lot of air from the engine compartment.

The "usual" drive ratio of a SBC mechanical water pump is between 1:1 and 1.3:1, over driven.

Most cars from 1960 and up used cross flow radiators. One of the reasons was a lower hoodline, and two, more cooling area was required to cool the larger engines. Cross flow radiators had a tank with an inlet/outlet placed on either side. The water entered on one side and passed through the core of the rad, was cooled by the air flow and the heat escaped through convection to the outside air. Engineers found that the longer the liquid was exposed to the cooling flow of air through the radiator core, the more heat could be extracted from the flowing water. They slowed down the water travel by increasing the size of the water pump pulleys, but that had its limitations. They also added more rows of core, but that too had limitations. Road course racers in 1969 found a way to keep cooling to a simple easy form. To do this, they pulled the tanks off the radiators that they were using and placed baffle plates in the tank covers. The baffles were placed so as to divide the radiator core section into three distinct areas. Water would enter the upper radiator inlet on the right side and would flow across the top section of the radiator to the left side, a baffle plate located 2/3rds. of the way down the tank caused the coolant to flow across the radiator to the right side to the right radiator tank. The coolant couldn't rise upwards because a baffle plate located 1/3rd. of the way down stopped it and forced it to head down lower in the right tank, where it again was drawn across the radiator core to the lower left tank outlet and out to the engine. This serpentine course that the coolant took allowed the coolant to be cooled THREE TIMES by the cooling air flow coming through the core area. "Excellent idea!" you say, “Why don't they do that to all cars today?” In a closed course environment, the theory works, but in real everyday life the average auto would never warm up to operating temperature during the daily commute.