Tools modded green hub fan clutch (1 Viewer)

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Otter

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finished installing the modded clutch and it works great! Belts didn't squeal at all. A/C blows a helluva lot colder!

Kevin, another job well done. Thank you sir!:clap:
 
Another Tools upgraded fan clutch. MInes still kicking booty :D
 
Any details on this? I tried searching green hub fan clutch and nothing came up. I need to replace my fan clutch soon.
 
Any details on this? I tried searching green hub fan clutch and nothing came up. I need to replace my fan clutch soon.

I think the green hub has been seen on the 3fe engines. Mine is a 1991. I think Redmuttonchops has a red hub on his 62 3fe. I'm not sure where Kevin got the other green hub.
 
Ohhh ok. Mine is a '97, so I guess I need the blue fan clutch?

Nothing is particularly wrong with my fan clutch now, but I need to take it off to do other seals and stuff and will be making a long interstate drive in a couple of months, so I would like to make sure I don't run into any issues. 220k on the clock so I am thinking I should change it now?
 
Ohhh ok. Mine is a '97, so I guess I need the blue fan clutch?

Nothing is particularly wrong with my fan clutch now, but I need to take it off to do other seals and stuff and will be making a long interstate drive in a couple of months, so I would like to make sure I don't run into any issues. 220k on the clock so I am thinking I should change it now?

If it is original, id have it rejuiced or replaced, they isually wont be very efficient at this point and being in AZ, a good idea.
 
Kevin, how thick did you go? I've got 100K cst in the :princess:'s and it's been just fine even at prolonged highway speeds.

***EDIT***
Never mind, saw the build thread after I posted.
 
What do you recommend Tools? 24k?

Any talk of viscosity is worthless without knowing the type of clutch. They all have differing design/shearing area, so a pic to help in clutch id would be the first step.
 
Kevin, how thick did you go? I've got 100K cst in the :princess:'s and it's been just fine even at prolonged highway speeds.

***EDIT***
Never mind, saw the build thread after I posted.

I'm guessing; it is a new type blue hub? Does it bark/slip the belts after a heat soak? I have never found that limit on the newer type blue. One of my suspicions/observations; due to the power neutered design, at some point the performance plateaus, thicker viscosity makes little/nothing in added performance?
 
It is a newer style blue hub. No belt slip at all.

You might have a point with your theory, but it sure moves more air than the my blue hub with 30K.
 
It is a newer style blue hub. No belt slip at all.

You might have a point with your theory, but it sure moves more air than the my blue hub with 30K.

Good deal. The most that I have tried is 30K, thinking of ordering 50K next time.

In talking with some way smarter about these fluids than I, there are a couple of characteristics of the fluid that limit how far it can be pushed:

When heavily sheared (high viscosity with small shear area, like the late type blue hub), at some point, it will produce more heat than shear (torque transfer). More heat effectively reduces viscosity, making the process cascade, get worse. The heat oxidizes the fluid, shortening it's life.

If this continues, at some point, the fluid goes into a state where the shear is 10% or less of original. This is reversible, when the extreme shear is removed, allowed to cool, it returns to the original state.

This would explain why the clutches with smaller shearing area are never as strong as the ones with larger area. Take a black/aqua/early blue hub, with 10K in it and it will bark/slip properly tensioned belts, when quick snap revved after a heat soak. They attempt to pull your laundry through the grill.:hillbilly: I have never been able to get that type of performance from a blue hub. Even worse is the red hub, regardless of viscosity are always weak, when stressed they fall flat, when allowed to cool, return to feeling somewhat strong.

From what I have been told and my observation agrees: The strongest clutch is one with the most shearing area. This needs less fluid viscosity to deliver good torque, the fluid is beat up less, will last longer and will deliver the most consistent torque drive when stressed.
 
That does it! I need a better fan clutch....where do you source ones with more sheer area than blue? My blue only lasts a couple years before it needs to redone:mad:
 
The only clutch available from Toyota is the neutered blue hub. The only "upgrade" path is used. That said, it should last longer than a couple of years, maybe try different fluid?
 
The only clutch available from Toyota is the neutered blue hub. The only "upgrade" path is used. That said, it should last longer than a couple of years, maybe try different fluid?

Could be...I think you did it the first two times. What truck am I looking for at a pick n pull for a green or black hub??

My benchmark is if (with pusher fan) the temps climb to 211+ while sitting in a drive through and will come back down if I use my hand throttle to lock the idle at 1500 then it is time to redo the treatment
 
Could be...I think you did it the first two times. What truck am I looking for at a pick n pull for a green or black hub??
...

The green one is for the 2/3F motors, different spacing. The black hub came on '93 and some '94 rigs, rare. The early blue is really rare, I have only seen two, likely an early (late 90's) dealer replacement?

Maybe try an Eaton, good clutch, original on '95-'97 rigs. I may know where a good one is, will check.

There is the possibility that other clutches may work, have similar mounting and more powerful, like from Tundra, Sequoia, Taco, etc. Have had zero luck in getting mounting comparison info from parts suppliers.
 
Good deal. The most that I have tried is 30K, thinking of ordering 50K next time.

In talking with some way smarter about these fluids than I, there are a couple of characteristics of the fluid that limit how far it can be pushed:

When heavily sheared (high viscosity with small shear area, like the late type blue hub), at some point, it will produce more heat than shear (torque transfer). More heat effectively reduces viscosity, making the process cascade, get worse. The heat oxidizes the fluid, shortening it's life.

If this continues, at some point, the fluid goes into a state where the shear is 10% or less of original. This is reversible, when the extreme shear is removed, allowed to cool, it returns to the original state.

This would explain why the clutches with smaller shearing area are never as strong as the ones with larger area. Take a black/aqua/early blue hub, with 10K in it and it will bark/slip properly tensioned belts, when quick snap revved after a heat soak. They attempt to pull your laundry through the grill.:hillbilly: I have never been able to get that type of performance from a blue hub. Even worse is the red hub, regardless of viscosity are always weak, when stressed they fall flat, when allowed to cool, return to feeling somewhat strong.

From what I have been told and my observation agrees: The strongest clutch is one with the most shearing area. This needs less fluid viscosity to deliver good torque, the fluid is beat up less, will last longer and will deliver the most consistent torque drive when stressed.

The science seems sound.

In my experience with the 100K cst in a newer blue hub, it pulls some serious air through the radiator. So much in fact that the JDM fan appears to be humming away at full speed even when off. My '94 (with a blue hub and 30K cst) doesn't even come close to that kind of air flow.
I have the original black hub clutches out of the 93 & 94. Those have both been drained and refilled with 3K cst. The plan was to use them once the temps around here get below 80 again...sometime in November :hillbilly:. I'll also be ready for a quieter ride since both fans in "summer" trim howl.
 

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