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Before I switch my current electric fan to another electric fan (high speed is dead), how much space is needed for a clutch fan?
The reason I ask is that I currently only have 4 inches from the pulley face to my radiator (455 is in a '64 c10). The pump is a GMB 6" length shaft (model GMB 130-1260P) so there is an opportunity to gain roughly another inch with the shorter shaft pump.
Hayden released a thermal clutch that’s much shorter than the factory clutch. It’s so shallow it’s a real pain in the *** to get the nuts on the water pump studs. You need to start all 4 nuts, then tighten them a little at a time while spinning the fan. Tightening one nut will bottom out the clutch on the remaining nuts.
I think Hayden has lengths specified in the catalog.
I have a 455 in my dads 81 GMC, there is a ton of room between the water pump and radiator. I never would have guessed the engine bays of the earlier trucks were that much tighter than the later years.
Hayden released a thermal clutch that’s much shorter than the factory clutch. It’s so shallow it’s a real pain in the *** to get the nuts on the water pump studs. You need to start all 4 nuts, then tighten them a little at a time while spinning the fan. Tightening one nut will bottom out the clutch on the remaining nuts.
I think Hayden has lengths specified in the catalog.
I have a 455 in my dads 81 GMC, there is a ton of room between the water pump and radiator. I never would have guessed the engine bays of the earlier trucks were that much tighter than the later years.
I actually found the clutch you're talkimg about and plan on getting one. There would be a few more inches of space if I used the smaller radiator for the straight 6. To use a v8 radiator you have to mount it about 4 inches back. That part sucks.
Hayden has a catalog with SD (standard duty) and HD (heavy duty) fan clutches with a great many snout lengths. It’s a matter of looking at the performance characteristics of the clutch (like what temp it kicks in) and snout length to figure out which one will work for you. I have a post on here somewhere about all that stuff. Where I wound up, very happily, was a Hayden 2747 standard duty and 7 blade fan for my ‘66 big car.
My cars are ‘66 Starfire with AC and ‘66 98 without AC. Both have 455s and high fin density 4 core copper brass radiators.
Here are my notes from 2016:
“Hayden clutch fans 2705 SD, 2747 HD, 2765 SD, all fit. but 2747 has .5" radiator clearance and is both cool and very noisy. 2765 runs quieter but hotter. 2747 with 7 blade deep fan runs noisy. Get shallower 7 or 8 blade fan. Check Hayden 2772, 2797, seems like it will be too long in overall length. Added 2747 to 6 blade quiet fan 4/16. Switched to 6 blade and 2765 in 12/16.”
The only other thing to mention is that if you car has or had the masticated rubber curtains in _front_ of the radiator, make sure these are in good enough shape and condition to force air through the core and inhibit or prevent cool air from going around it. I know nothing about front shrouding on a C10.
A good clutch fan, 6 or 7 blade fans, shroud and curtains have solved my overheating problems pretty completely.
Mainly, have a good look at the Hayden online catalog and test a few correct-diameter fans and I suspect you’ll get where you want to go. GM varied the pitch and blade numbers of fans a lot over the years, testing helps you find the one the is quiet enough to be unobtrusive while still pulling enough air to keep the vehicle cool.
Hayden 2947 is the short one and it is difficult to install but it can be done with short studs and shaky hands. It engages at 175 which is air temp and did not really improve over my stock 4 blade with its 6 blade. Kit Master makes adjustable clutches but they take a 6 bolt fan and I think they will be too heavy
May 25th, 2022, 06:39 PM
