Installing an Oil Cooler for Performance, Reliability and Efficiency By: Jean Genibrel
Owners of Cobra kit cars would benefit from using coolers with side mounted plumbing. This would allow the use of straight fittings that would improve flow, appearance and cooling.
Cooling the oil in your race or performance motor is essential for performance and reliability. Not to be forgotten are motor-homes, tow vehicles, off road vehicles, and any and all vehicles that may encounter extremes in hot weather or increased load. Overheated oil can ruin an engine, and it will affect performance. Installing the proper size oil cooler, in the right place, with the correct fan is primordial in the endeavor to maintain oil temperatures within a safe range. There are other small factors that often go overlooked such as the appearance of the install and the method of mounting the cooler.
Oil coolers (and radiators) should never be mounted solidly to the car. Rubber vibration isolator mounts should be used to absorb vibrations and chassis flex. Oil coolers are built with thin aluminum and a cooler full of oil and weighed down with fittings, a fan and hoses can be quite heavy. That weight, accentuated by forces induced by bumps in the road, and engine and chassis vibrations can easily crack the frame of the cooler and cause irreparable damage. In off-road racing, a solid installation will not last very long, and the car will probably not see the end of the race. Rubber mounts and mounting brackets are sold by APPLIEDSPEED.COM to prevent this problem.
Rubber vibration isolator mounts should be used to absorb vibrations and chassis flex. The weight of the cooler full of oil added to the weight of the hoses and fittings accentuated by forces induced by bumps in the road, and engine and chassis vibrations can easily crack the frame of the cooler and cause irreparable damage.
Another mounting method to avoid is using tie-straps through the fins of the radiator behind which the oil cooler is mounted. While this method is acceptable for mild street use or towing, in racing conditions, certainly on a dirt track, or in off-road racing, the fins will bend and cause the cooler to come loose and eventually fail.
Plumbing the cooler is also vital for efficiency and appearance. If you are appearance conscious when plumbing a show car or a replica, try to run the lines in such a way that they are out of sight. Typical of this is the Ford Cobra replicas with the cooler in the front cowling. Running the cooler in a different location with a fan may be a better option for appearance and cooling efficiency. Installing the cooler sideways with the fittings pointing to one side will hide the hoses, and it will yield some additional cooling to the engine. Certainly, running a cooler with fittings coming off the ends would solve this problem.
Stadium trucks have complete compartments dedicated to the cooling of the trucks. These enclosures include fans, oil, power steering, transmission, rear end and power steering coolers.
The fittings to use are also very important. A 90-degree cast fitting equals 2.5 times in feet of hose in the amount of pressure drop. While a smooth fitting like an AN bent tube type only obstructs the flow marginally.
Complete oil cooler installation kits are available from suppliers like Appliedspeed.com. Shown here is the sandwich adapter that also serves as thermostat, fittings, clamps, tie straps and rubber pads to avoid metal to metal interference.
Ninety degree cast fittings (A) are very detrimental to oil flow. One of those fittings can reduce pressure by as much as five PSI. With increased turbulence comes an increase in temperature. A bent tube AN style fitting (B) allows for lower pressure drop and improved cooling. What is more, those fittings are much more eye-pleasing.
The orientation of the cooler also affects the operation. Oil, whether for an engine, transmission or rear axle, is typically full of air bubbles. Installing a cooler with the hoses pointing up or down may cause air pockets to form inside the cooler. Mounting the cooler with the hoses pointing to the side with the intake at the bottom will greatly reduce the formation of air pockets in the cooler.
When space is tight the installer can mount an electric fan to the cooler like this Derale 15800 kit from Appliedspeed.com. The kit includes fittings for push-on hose or -8 AN fittings.
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