I think the cooling systems on these engines is a big part of their draw as a hobby. I mean, just look at us!
It's a problem (or potential problem) that remains unsolved (or unsettled, anyway) and every person on this thread gets all excited trying to figure out the best approach.
When I look at the cars on the Spyder forum—mostly running 2165s and larger—I see some bizarre looking cooling practices. Chutes and shunts abound; one guy has (had?) his remote oil cooler bracketed up by the twin grills with a fan trying to push air out—directly fighting DTM shroud fan which tries to draw air in. Clearly the Spyder body does not, by itself, make adequately cooling grumpy flat-4s an intuitive task.
As a relative noob I intend to watch and learn, and see how the engine in my Spyder does with no external oil cooler. The Spyder guys had a damn conniption over this: You fool! No one goes without!
Reminder: mine is a Raby 1914 with a DTM and, afaik, stock to his 2007 specifications. I've built a full, louvered underpan to separate the exhaust pipes from the topside cooling and carb air intake, and am itching to get it underway and see how it works (or doesn't).
Given how my theories have panned out so far, I figure I have less than half a chance of being right about this. Hoping to get the oil temp gauge on the dash working properly sooner than later in this process.