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clutch fan conversion

D-Rat

Fartknocker
Joined
May 20, 2020
Member Number
664
Messages
304
Loc
Mesa, AZ
I have a '77 with a 351M that's pretty much stock....it has a spacer and a 7 blade flex fan that I know is crap. I'd like to do a clutch fan conversion and go with the OEM 7 blade fan that was avaialble...The question is on the spacing.....if anyone has done this, did you still need any type of spacer to get the fan inside the shroud when using a fan clutch? I'm having a hard time finding any info on how thick an OEM fan clutch is.....

It's a longshot but maybe someone here knows.
 
Planning to do the same. Looking for specific PNs or make/model/yr application that I can buy a clutch and fan for. spacer should be easy enough. From my research so far the bolt patterns are shared with GM apps.
 
As long as the fan is at least halfway in the shroud and an inch or more from the radiator your golden.
 
As long as the fan is at least halfway in the shroud and an inch or more from the radiator your golden.

Yeah, but I also don't want it hitting my AC compressor....the current fan has about 3/4" clearance on that.
 
You each have nice trucks, with AC, in the desert, is there not a good enough electric fan solution?

I understand that maybe you're looking for simplicity/ reliability, but I've been on many tail rides pinching off fins, babying a 70s or 80s full-size after it flexed out and made "the noise "
 
Electric fans work well for cars that don't have the huge cooling demand range, and all OEMs use them. For trucks a clutch-type is still the recipe for moving a shit-ton of air, when needed. And yes, for reliability.

The Taurus/T-bird is generally regarded as the better single blade, and even dual high RPM (noisy as hell) fans that draw 40-50 amps don't come close to a big ass mechanical. 50 amps at 13V is only 650 W = 0.85 hp. A clutch fan can deliver way more than 1 hp. The electric setup also has to convert energy twice instead of not at all, mech->elec->mech.

E-fans have better efficiency due to tight shroud gap that just can't be had with the mech setup due to chassis/engine flex. I'm using tight custom motor mounts and will build a custom shroud to minimize loss. Assuming I can get it to all to fit.
 
I understand that maybe you're looking for simplicity/ reliability, but I've been on many tail rides pinching off fins, babying a 70s or 80s full-size after it flexed out and made "the noise "

Don't run worn the fuck out motor mounts and it's not an issue.
 
FWIW, the clutch fan positioned the fan exactly where it was when it was directly driven off the water pump with the spacer.
 
can you share pic and part numbers?

Ugh, sorry, I chucked the box that it came in. Got it from a member of another site...was a NOS part. Look up what fits a 78-79 M motor and you should be good. The fan I got was used, so no part number on that either, but it's an OEM 7 blade fan.
 
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