Requesting cooling/radiator/fan help for a slant six
Gurus of the forum, I am soliciting some real-world feedback on radiators, fans, and cooling. Opinions and theories are also happily accepted!
My car is an almost completely unmolested 66 Valiant, currently sporting the original /6 with 3-speed column shift. I am in the process of building this into a fun sleeper, keeping the slant but upgrading all the undercarriage systems, and swapping to an A833OD and 8-3/4 rear end. It is projected to make about 170 HP and about 230 ft/lbs of torque when done.
When I got the car, it was leaking badly everywhere, so I got everything fixed including a new radiator as documented in this thread.
Then while cruising forums in my eternal quest for knowledge, I found this video dealing with HP loss due to the type of fan. The bottom line was, if using a belt-turned fan a clutch fan setup has the least drain on performance.
Engine Masters fan test:
This test made me think with HP and performance coming at a premium for the slant, minimizing HP loss would be a good idea. Further digging indicates the only hope for an early A and a clutch fan came in a few threads stating a setup from a late 70’s MB 280SE will bolt right up, and is much more compact when trying to get it to fit between the water pump mount and the radiator. So, I order the clutch and fan, which sure enough are quite a bit thinner. Together they measure only 2-1/2” total depth. This would be great news, except the Champion radiator I installed is a 3-core and quite thick. I have only 2” clearance between the water pump and the radiator.
So, this brings me to my questions on radiators, fans, and cooling. If I were to repair my original radiator, I would have plenty of room for the MB clutch and fan. The factory unit measures 19”x17”, and only two cores. The Champion is 22”x17”, and is a 3-core. I can run the Champion with a fixed factory 4-blade or 7-blade fan (big HP drain). I can run the repaired original radiator with the MB clutch fan (very little HP drain).
My experience with slants back in the 70’s was they just about never overheated, but that was with a stock engine. Would my mildly built slant do OK cooling-wise with the original two core radiator and the MB clutch fan? If so, that would be my preference as it would drain less HP, and look much more stock to fit in with the sleeper mode.