NPD typically lists the OE Ford part number and aftermarket manufacturers part number at the bottom of the listing.

There are 2 basic Hayden fan clutches to use.. both are heavy-duty, thermal units. The 2710 has an overall height of 3.30 inches and a fan-mount height of 1.75 inches. The 2711 has an overall height of 2.98 inches and a fan-mount height of 1.40 inches but otherwise are identical. The shorter clutch is an option when installing a deeper, multi-core radiator.

As for fan shrouds... many people confuse their purpose. They are designed to shroud the fan blade tips to reduce air vortices and improve efficiency, just like the "winglets" at the ends of the wings of modern airplanes. The more efficient the fan blades, the lower the air pressure differential between the front and back side of the fan allowing the air to move. Uncontrolled vortices of air can cause turbulence to build up at the fan tips that inhibit air flow. The most efficient shrouds will leave part (up to half) the width of the fan blade tip unshrouded to allow the vortices to escape.

 

Thanks Bart, all good nuggets of info. I'll look for the shorter of the two clutches, sinse my RAD is a 4 row. The "multi-core" Rad aspect didn't enter my mind. Not considering this, could have resulted in a "return to vendor" situation.
I am aware of shroud design and the "vortex" efficiencies from your previous posts on the subject and have advocated the 50% inner/outer aspect too. Thanks for reiterating.

 

Well, it doesn't look promising if my calculations are correct with yours..
I just measured from the face of my W/P pulley to the RAD surface, it's 4.250". If I interpret your numbers correctly of 2.98 and 1.40, these equal 4.38". I don't have the distance with 4.250....? I need a thinner clutch (1.35?) as I need to allow for, at least installation room of 1.250-.500?

 

No, 2.98" is the entire depth. The fan mounts 1.40" from the flange. Typically, the fan mount is centered halfway across the width of the blades....

 

This might help you visualize the clutch dimensions

 

Thanks for the chart, it's very useful. What is the recommended distance from the RAD surface to the Clutch surface? We know fans should 1-1.50". Since the thermal aspect of the clutch now comes into the equation, is there an optimal distance for the thermal properties of the clutch operation to be considered?
In my situation, I have 4.500" between the surface of the RAD and the W/P pulley surface. Edited to change available distance.

 

I don't think it matters , the clutch works by the temperature of the air passing over it, not the radiated heat from the fins.

 

Thanks. After posting this question I later spoke with a Hayden Tech. His recommendation, was in keeping with what many of us here have mentioned, position the blade 50/50 within a shroud and, if possible, the clutch face approximately 1” from the RAD surface. I mentioned I’m using a 3.1 ( 2710) Hayden together with a 17” blade and 4 row RAD. He highly recommended a shroud in all cases for maximum effectiveness.
My current setup has been in place 18 years, or so, with no signs of over heating. I do run the un-popular 17 Flex-a-lite blade or “ shred-a-lot”, as it has become famously named. lol