71 mustang 351c adding clutch fan

[tony-muscle]

Thanks. I miswrote. The spacer i was talking about is part of the clutch so all i need is a clutch with a shorter "shaft". I will lookup those numbers.

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[tony-muscle]

I was looking at my fan clutch and I do have some sort of spacer. I have forgotten about it.

Please look at the picture and tell me if this is normal. If I reduce this spacer or eliminated I should be able to pull the blades back enough. However, they may be too close to the pulleys and belts.

 

[Hemikiller]

Nope. that's not normal at all. Clutch bolts directly to the face of the water pump pulley.

 

[tony-muscle]

Nope. that's not normal at all. Clutch bolts directly to the face of the water pump pulley.

Thanks. I guess that explains why my fan is so forward. In a "normal" installation, how close are the fan blades too the pulleys? Once I remove the spacer they will be very close in my case.

 

[B229218]

Nope. that's not normal at all. Clutch bolts directly to the face of the water pump pulley.

Thanks. I guess that explains why my fan is so forward. In a "normal" installation, how close are the fan blades too the pulleys? Once I remove the spacer they will be very close in my case.

Well, normal blade depth past shroud opening on a FLEX fan is 1/4  width of blade, looking down from above, this allows for flex action to nearly close the gap, proving maximum cooling. Now a clutch fan has no flex, my stock ranger flex fan centered 1/2 enshroud opening.

 

[jspears]

I had a flex fan and it would pull a lot of air all the time, it would roar. i bought a hayden 2747 fan clutch and a derale 17117 fan. I loved the quiet at idle and part throttle, but by 3000rpm it started to roar and at 3700 the belt would squeel. I could have tightened the belt but I wanted to use less horsepower not more. I ended up grabbing a 1989 ranger 2.3l clutch fan and trying that. the fan is about 4 inches from the radiator and has no shroud yet but it keeps the engine cool even when idling for 40 minutes. car has a manual transmission and is running 800 rpm idle, 28 degrees timing advance and the idle is adjusted pretty lean. no air conditioning yet.

 

[Ironman77]

Thanks to Hemikiller and all others for the great information on the fan, fan clutch and thermostats.

I was having overheating issues with my 1971 Mach 1 with 351C-4V and A/C. After reading the info here I decided to check the fan and thermostat. The PO had a 17" fixed blade fan (too small) with a 2-1/2" spacer (no clutch) which caused the fan to be too far in to the fan shroud and not drawing air properly through the radiator. When the fan is too far in the shroud, it causes turbulence in the fan shroud and does not draw air through properly. I removed the fan and spacer and replaced the fan with a 18" Derale 17118 clutch fan and a Hayden 2710 clutch (no spacer) from Summit Racing and used the clutch fan stud bolt setup from Auto Zone. Now the fan protrudes out a 1/4" of the back (engine) side of the fan shroud. I checked the thermostat and the PO had a Windsor thermostat and not a Cleveland "hat" style, so changed that out to Murry 195 degree Cleveland "hat" style from O'Reilly Auto Parts. Also, I did a good flush of the radiator and added fresh coolant. 

It has been between 95 and 100 degrees outside here in Texas the last week and I've have had no issues with overheating even when idling and the A/C is blowing super cold air.