Cool/Heat: UPDATED: Replacement 6-blade Fan & Viscous Clutch Question

[r1lark]

A while back I purchased a six-blade fan and viscous fan clutch from a fellow Studebaker fan, who had purchased them from one of our Studebaker vendors. (I'm trying to find out which vendor that was, hopefully will hear soon.) The fan clutch has been modified to fit the Studebaker V8 water pump hub.

Anyway, was planning to install this on my '64 Daytona 4-speed, along with a factory shroud. When I got to looking at the fan, I noticed the sticker on the fan listed the max rpm as 4000 rpm. I have never seen something like this, especially surprised at the relatively low rpm this fan is rated at. Not going racing in this car (at least not yet ), but when you have a four speed it's fun to run the rpm up through the gears.

Pictures are below. Anyone seen a fan like this that is only rated at 4000 rpm??

Sorry for the blurry pic on this one:

[JoeHall]

I believe the 4000 RPM rating means, no matter how high the engine revs, the fan is limited to 4000 RPM, due to its internal slippage, as designed. Some thermal fans are rated by percent, i.e. will never exceed 80 percent of engine RPM, but I believe your viscous is rated as mentioned. But I could be wrong, I am just a pilgrim.

[r1lark]

Joe is correct. The vendor, Dave Thibeault, provided the following information:

The fan is rated for 4000 RPM fan speed not engine speed. The fan clutch will not transmit enough torque to spin the fan that fast. It is marked that way so someone will not try and run the fan without a clutch. Those fans are very efficient at low speed and the fan clutch limits the speed. So there is no problem. The torque limiting fan clutch will allow the fan to spin at about 3000 ROM fan speed maximum.