Bulletproof cooling system
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| − | [[ | + | [[File:Engine-cooling-system.jpg|thumb|600px|right|Typical cooling system, some engines use an internal bypass]] |
==How the cooling system works== | ==How the cooling system works== | ||
| − | + | {{Note1}} All temperatures are in degrees Fahrenheit. | |
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The cooling system works by absorbing, transporting, and dissipating heat. Therefore, anything that impedes any of those functions can cause overheating: | The cooling system works by absorbing, transporting, and dissipating heat. Therefore, anything that impedes any of those functions can cause overheating: | ||
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*Oftentimes, the cheapest and most bulletproof way is to use the largest radiator that will fit, along with the fan type and size, and shroud that was designed for the radiator from the factory. | *Oftentimes, the cheapest and most bulletproof way is to use the largest radiator that will fit, along with the fan type and size, and shroud that was designed for the radiator from the factory. | ||
*Use a full shroud, with the radiator positioned so that the fan blades are half-in and half-out of the shroud hole, 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). | *Use a full shroud, with the radiator positioned so that the fan blades are half-in and half-out of the shroud hole, 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). | ||
| + | [[File:Thermo fan clutch.jpg|thumb|210px|Typical thermostatically controlled fan clutch]] | ||
*Fan recommendations: OEM 18 inch, 7-blade steel fan with 2" to 2-3/4" pitch. The 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) may not move enough air at idle and low engine RPM to cool the engine properly. | *Fan recommendations: OEM 18 inch, 7-blade steel fan with 2" to 2-3/4" pitch. The 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) may not move enough air at idle and low engine RPM to cool the engine properly. | ||
| − | *When possible, use a thermostatically controlled fan clutch. 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 if left undiagnosed. Sometimes they may appear to be OK when cold but they will free-wheel when hot. | + | *When possible, use a thermostatically controlled fan clutch. 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 if left undiagnosed. Sometimes they may appear to be OK when cold but they will free-wheel when hot. <br style="clear:both"/> |
*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 1:1 works better. Most 1960s muscle cars are 1:1. Sustained pump speeds over 4200 rpm can cause cavitation. Race vehicles may use a 2.3:1 ratio for a 9000-plus rpm engine. | *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 1:1 works better. Most 1960s muscle cars are 1:1. Sustained pump speeds over 4200 rpm can cause cavitation. Race vehicles may use a 2.3:1 ratio for a 9000-plus rpm engine. | ||
*On a carburetor-equipped engine, often a 180º thermostat is used, although a little hotter thermostat rating (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 combustion, such as moisture and acids which form and get into the oil. Motors using EFI induction should use the thermostat temperature specified by the factory for that particular motor to prevent false input to the computer and consequent problems. The sensor pill goes toward the motor. | *On a carburetor-equipped engine, often a 180º thermostat is used, although a little hotter thermostat rating (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 combustion, such as moisture and acids which form and get into the oil. Motors using EFI induction should use the thermostat temperature specified by the factory for that particular motor to prevent false input to the computer and consequent problems. The sensor pill goes toward the motor. | ||
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