A fan forced oil cooler will save the oil from damage if the engine is also kept cool. But, this motor is not significantly oil cooled. Wasn't designed that way. The engine metal mass dominates the oil temperature.
The dog wags the tail, rather than the tail wagging the dog. (Unless your point of view is that of a flea on the tail.
)
See all those fins around the motor? That's where the engine sheds most of its high heat into the air that is moving past them. Actually, the entire external surface area of the motor sheds heat into surrounding air, too. But, most of the fins and the largest of the fins are located as close to the combustion point as possible, in the desire to shed the heat into the air as soon as possible.
If the air in contact with the fins reaches the same heat level as the fin metal surface, the heat does not move and increases in level toward that of the source, which is the combustion chamber flame kernel, or something around 2000 degrees. Since the pistons melt or seize before that temp is reached, there will always be some temperature differential in a
running engine as it sheds heat faster than it can heat soak. But, I've seen exhaust headers glow cherry red, which is about 800 degrees. To get that, the exhaust gasses must be of much higher temps.
I'd say the car fan addition idea, or a few smaller computer fans directing air over the fins would be prudent in this engine while spending more time stationary than moving, just to get the higher heat air away from the fins and replace it with cooler surrounding air. Keep the engine cooled and the oil will be also be cooled. You don't really need gale force winds to keep this engine cool (unless it is actually producing max power and the most heat generation possible). But, you do need a constant air replacement scheme to keep from having the temps build up.
Think of it this way; saving this motor is cheaper than buying a replacement.
Rock on!
