302 Fan Orientation
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Senior User
Joined: Jun 2017
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This is just what came with the truck when I bought it. Care to let me know what a better option is
Lead Driver
Joined: Apr 2007
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From: Houston
For Non AC trucks you had a 5 bladed flex fan. For Factory AC trucks you had a 7 bladed flex fan, 5 bladed clutch fan or a 6 bladed clutch fan.
I personally bought a Flex-A-Lite 7 bladed flex fan to upgrade my standard duty non AC 5 bladed flexfan. I couldnt source a NOS unit but this aftermarket unit is the same diameter as my 5 bladed flex fan but should be 1/2" bigger diameter based off fords parts and illustration guide for the 7 blade flex fan.
Many people actually avoid flex fans due to the risk they pose of coming apart but all my Fords except for my Fairlane has a OE flex fan and they have never came apart.
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Well these trucks had two kinds of fans from the factory, they had a flex fan or a rigid fan mounted to a clutch.
For Non AC trucks you had a 5 bladed flex fan. For Factory AC trucks you had a 7 bladed flex fan, 5 bladed clutch fan or a 6 bladed clutch fan.
I personally bought a Flex-A-Lite 7 bladed flex fan to upgrade my standard duty non AC 5 bladed flexfan. I couldnt source a NOS unit but this aftermarket unit is the same diameter as my 5 bladed flex fan but should be 1/2" bigger diameter based off fords parts and illustration guide for the 7 blade flex fan.
Many people actually avoid flex fans due to the risk they pose of coming apart but all my Fords except for my Fairlane has a OE flex fan and they have never came apart.
For Non AC trucks you had a 5 bladed flex fan. For Factory AC trucks you had a 7 bladed flex fan, 5 bladed clutch fan or a 6 bladed clutch fan.
I personally bought a Flex-A-Lite 7 bladed flex fan to upgrade my standard duty non AC 5 bladed flexfan. I couldnt source a NOS unit but this aftermarket unit is the same diameter as my 5 bladed flex fan but should be 1/2" bigger diameter based off fords parts and illustration guide for the 7 blade flex fan.
Many people actually avoid flex fans due to the risk they pose of coming apart but all my Fords except for my Fairlane has a OE flex fan and they have never came apart.
Lead Driver
Joined: Apr 2007
Posts: 5,958
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From: Houston
To me I personally prefer a flex fan as the fan is always spinning 1:1 speed with the water pump pulley and doesnt slip like a clutch fan that may be spinning at say 80% of water pump speed. I also like flex fans for the fact the blades are a bit more aggressive so at idle there is a whole lot more air flow at idle which for a converted R12 to R134A ac system is better. Its why I opted for the 7 blade flex fan as browsing my parts and illustration guide my truck with dealer AC didnt get the fan replaced it still uses the 5 blade flex fan when it should be a 7 blade flex fan if it is a flex fan and not a clutch fan. I am doing the upgrade with my new engine with the hopes of being able to get my dash vent temp below 58* F on a 100*F day.
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Depends on who you ask. A thermostatically controlled clutch fan would slip more till the thermostat on front gets hot then it will lock up more and spin faster and faster. Problem is I couldnt ever find a thermostatically controlled fan clutch for my truck when looking. Everything was rpm based and HD and I refused to get HD as I had one on a 89 E150 van and it howled like a radial engine prop plane taking off when you accelerated.
To me I personally prefer a flex fan as the fan is always spinning 1:1 speed with the water pump pulley and doesnt slip like a clutch fan that may be spinning at say 80% of water pump speed. I also like flex fans for the fact the blades are a bit more aggressive so at idle there is a whole lot more air flow at idle which for a converted R12 to R134A ac system is better. Its why I opted for the 7 blade flex fan as browsing my parts and illustration guide my truck with dealer AC didnt get the fan replaced it still uses the 5 blade flex fan when it should be a 7 blade flex fan if it is a flex fan and not a clutch fan. I am doing the upgrade with my new engine with the hopes of being able to get my dash vent temp below 58* F on a 100*F day.
To me I personally prefer a flex fan as the fan is always spinning 1:1 speed with the water pump pulley and doesnt slip like a clutch fan that may be spinning at say 80% of water pump speed. I also like flex fans for the fact the blades are a bit more aggressive so at idle there is a whole lot more air flow at idle which for a converted R12 to R134A ac system is better. Its why I opted for the 7 blade flex fan as browsing my parts and illustration guide my truck with dealer AC didnt get the fan replaced it still uses the 5 blade flex fan when it should be a 7 blade flex fan if it is a flex fan and not a clutch fan. I am doing the upgrade with my new engine with the hopes of being able to get my dash vent temp below 58* F on a 100*F day.
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Lead Driver
Joined: Apr 2007
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From: Houston
Nothing wrong with what you have. Youll just burn a bit more fuel as that rigid fan will be pulling air at all engine speeds. My '56 has a OE rigid 4 blade fan and it cools just fine doesnt really make any noise but I am sure if I calculated miliage it would be lower fuel economy than if I took it off and replaced it with a clutch fan.
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Senior User
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Depends on who you ask. A thermostatically controlled clutch fan would slip more till the thermostat on front gets hot then it will lock up more and spin faster and faster. Problem is I couldnt ever find a thermostatically controlled fan clutch for my truck when looking. Everything was rpm based and HD and I refused to get HD as I had one on a 89 E150 van and it howled like a radial engine prop plane taking off when you accelerated.
To me I personally prefer a flex fan as the fan is always spinning 1:1 speed with the water pump pulley and doesnt slip like a clutch fan that may be spinning at say 80% of water pump speed. I also like flex fans for the fact the blades are a bit more aggressive so at idle there is a whole lot more air flow at idle which for a converted R12 to R134A ac system is better. Its why I opted for the 7 blade flex fan as browsing my parts and illustration guide my truck with dealer AC didnt get the fan replaced it still uses the 5 blade flex fan when it should be a 7 blade flex fan if it is a flex fan and not a clutch fan. I am doing the upgrade with my new engine with the hopes of being able to get my dash vent temp below 58* F on a 100*F day.
To me I personally prefer a flex fan as the fan is always spinning 1:1 speed with the water pump pulley and doesnt slip like a clutch fan that may be spinning at say 80% of water pump speed. I also like flex fans for the fact the blades are a bit more aggressive so at idle there is a whole lot more air flow at idle which for a converted R12 to R134A ac system is better. Its why I opted for the 7 blade flex fan as browsing my parts and illustration guide my truck with dealer AC didnt get the fan replaced it still uses the 5 blade flex fan when it should be a 7 blade flex fan if it is a flex fan and not a clutch fan. I am doing the upgrade with my new engine with the hopes of being able to get my dash vent temp below 58* F on a 100*F day.
Lead Driver
Joined: Apr 2007
Posts: 5,958
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From: Houston
Since you seem to know way more than me, could you help me decide what to do about my temperature gauge or lack there of one. I see the old sending unit in my intake manifold but it’s not hooked up to anything and I don’t know if it is even working or accurate so I was thinking I should replace it with either a mechanical or electric one with a new gauge. Just I’ve never done that before
Do you have an actual temp gauge or just a temp light?
If you have a OE gauge they arent exactly perfect, they will give you a normal range but wont tell you exactly what temp. Many change them out for aftermarket. If I were to change one out I would go with an electric one to be honest.
I am actually trying to get Dakota Digital to release their retro series of clusters for the 80-86 F-series/bronco as it looks more like the OE cluster but is all modern.
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Joined: Sep 2003
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From: SoCal
Here's my story with fans. When I put my 1968 302 together, I had a 4 blade rigid fan that came with the car. There were a couple times when I was stuck in stop-and-go traffic where I watched the temperature gauge climb near its top indicator. So I knew that configuration didn't work. I ended up getting a fan shroud, which reduced the biggest size fan I could to 16", and got a 6 blade flex fan. So when I had to drive in the same condition again, the temp gauge stayed solidly at its normal position, which I assume is where the thermostat opened.
I think Hot Rod or Car Craft had done tests and found that a rigid fan mounted on a thermal clutch was the best at cooling and minimizing parasitic drag. The clutch is supposed to lock up at low speed, like at idle, to drive the fan as hard as possible since that's where there is minimal natural air flow. It will normally slip more with increasing rpm, unless the air hitting it from the radiator starts to get hot. And the clutch is a viscous fluid between non-contacting plates, so it will never "wear out" like a disc clutch will. What usually happens is the enclosure holding the fluid develops a leak, and when the fluid leaks out, and power is no longer coupled to the fan.
I think Hot Rod or Car Craft had done tests and found that a rigid fan mounted on a thermal clutch was the best at cooling and minimizing parasitic drag. The clutch is supposed to lock up at low speed, like at idle, to drive the fan as hard as possible since that's where there is minimal natural air flow. It will normally slip more with increasing rpm, unless the air hitting it from the radiator starts to get hot. And the clutch is a viscous fluid between non-contacting plates, so it will never "wear out" like a disc clutch will. What usually happens is the enclosure holding the fluid develops a leak, and when the fluid leaks out, and power is no longer coupled to the fan.
Lead Driver
Joined: Apr 2007
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From: Houston
Yep you have to have a fan shroud only way you can get away without one is if your fan is right up against the radiator. Thats how my '56 is the fan is like 1" from the radiator cores and it doesnt over heat without a fan shroud. But on trucks like ours the fan blade is going to be at least 6" away and would require a shroud of some type to be effective at cooling.
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