|The MGA With An Attitude
Engine OIL COOLER Installation, Competition Type, 2 - OF-105C2
The following photos from Colyn Firth in South Yorkshire, UK, show a unique adaptation of the factory type competition oil cooler. The sheet aluminum after duct is well made but appears to be hand formed with irregularly spaced holes (hand drilled for installation). On the cooler there are self-tapped holes where the factory tag was fitted with screws as original.
The rectangular hole cut through the body air pan has removed most of the deeply embossed "X", so the air pan is more flexible. This may slightly reduce structural integrity in event of a frontal impact (likely little significance). It might result in some increased noise if the air pan may vibrate at certain resonance frequencies This may be dampened out by the new air duct and the oil cooler itself adding mass and stiffness to the air pan.
That bit of sheet metal is an interesting concept, but I don't know if it would work as intended. Fairly often an oil cooler is located below the air pan with a aperture cut in the valance panel for air inlet. This works because when the car is moving air immediately in front of the valance panel is at higher pressure than air aft of the valance (meaning air will flow through the hole in the valance panel). Problem is, I'm not sure that air immediately inside of the grille is at higher pressure than air below the air pan (behind the closed valance panel). There is some restriction going through the grill such that pressure will be slightly lower aft of the grille.
Absolute air pressure is relative in different locations. Increased pressure in front of the valance panel does not necessarily mean decreased pressure aft of the valance panel. Pressure aft of the valance panel may also be increased slightly, just not as much as in front. When the valance panel is turned under and back with lots of space below, pressurized air in front is forced under the car, which is possible to cause increased pressure and "lift" from underneath. Pressure below the air pan might be equal or greater than pressure above the pan. If so, that could defeat air flow through the oil cooler using the sheet metal duct in these pictures. I have an intuitive feeling that air flow will go the right way, but someone might have to measure air flow or pressure with car in motion to verify the concept.
On 1/21/2013, Bo Giersing wrote:
"I have attached page 25 from the 1958 Special Tuning manual showing the mounting instructions for this oil cooler. It shows the air intake ducts mounted on small pedestals to clear the wide oil cooler - these pedestals were still on 554 when I acquired the car. .... I have seen this oil cooler mounted on 2 other MGA's in South Africa".
Wow! Until this message I had no idea that the downward directed duct was an original factory fitment.