Fan clutch oil mod: mpg hit?

[surfpig]

I'm in the middle of a weeklong roadtrip, did two days of driving in 100-110 heat with a recently modded clutch. Temps have been 190-205. I'm on the coast now though. . .

If there's any difference in mileage, I can't tell.

 

[hawaiicruz]

13.5 MPG before I put 10k in my black hub and 13.5 after

 

[firetruck41]

I check, but don't mess with most of the valves. The exception is the Eaton clutches, lots of them come "on" at ~135-150F, so tune them to ~125F. Not sure that even matters, they are original to the rig, so have been working, cooling the rig for many years/miles before the fluid went soft?

This is the first reference to tuning the Eaton that I have seen. I just changed the fluid in my Eaton to 20k, and after a test drive, the fan spun too easily. after a little research I saw that you could adjust the blue clutch fan, but could find no reference to tuning the Eaton.

When changing the fluid, I did not notice any way to adjust the clutch, but I was not specifically looking, as I was just intent on changing the fluid. Any information in regards to tuning the Eaton would be appreciated.

 

[Tools R Us]

I adjust them by bending the spring to get the temp range that I'm aiming for. Look at the spring in this pic.

 

[firetruck41]

I adjust them by bending the spring to get the temp range that I'm aiming for. Look at the spring in this pic.

Thanks!

 

[Kernal]

What is the procedure for bending the coiled spring?

 

[firetruck41]

Well, I don't have the answer. I just tested it straight from the truck and it began to open at 160F. I bent the spring, and couldn't get it open at even 190F... oops. Bent it back and had it opening at 155F now. Not sure how much more I can bend it, but basically, I am kind of "squeezing" it with some pliers, now its at 165F, while I thought I was adjusting it lower... AARGH!

 

[firetruck41]

Now I'm back to 190!

 

[firetruck41]

So, I've got it fully open at 145, and am not going to touch it again. Basically, you have to squish the spring, and twist the coil in many different directions/manner/method, and eventually, it might get into an acceptable range. Heck, I think i did the same thing two different times, once got me to 190F, the other got me to 155F

 

[Tools R Us]

How are you measuring it, don't think that I have ever seen first opening that high on any clutch? I usually set them to ~120-130F first opening, fully open ~200F.

 

[firetruck41]

How are you measuring it, don't think that I have ever seen first opening that high on any clutch? I usually set them to ~120-130F first opening, fully open ~200F.

Put (half) the clutch in a pan of water with thermostat down, immersed in the water, then used low heat on the stove to warm it up until the hole began to open. I had a instant read thermometer suspended in the water and would stir the water a bit to make sure it was evenly heating up.

Straight off the truck, I got the tiniest opening starting at 160F. Explained alot... as I have been having higher than normal coolant temperatures (Scan Gauge II) this summer, and the new clutch fluid didn't seem to do much yesterday. Even after the new fluid and a pretty good heat soak, the fan spun freely for several seconds after shutting the engine off, and spun freely by hand.

Now, it opens around 100F, and opens up past the "halfway" mark at about 140-145F. Now the fan has some serious resistance after shutting the engine off, the fan stops immediately, and I don't get more than one blades worth of spin with a good shove of the fan with the engine off. I also can hear the fan working, and temps were cooler driving up a couple 1500ft hills nearby.

 

[e9999]

well, since we're diverging heavily from mpg issues, and the experts are already involved in the thread I'll throw this in:

can anybody tell what kind of clutch mine is from this pic? doesn't look like the Eaton pics I've seen. And no indication of blue paint or that it's been changed by PO. Is this an Aisin?

 

[firetruck41]

Looks like mine (pictured below), which I believe is an Eaton. Sorry to have derailed the topic, just had never seen another mention of adjusting the Eaton, after having searched a bunch.

 

[Tools R Us]

It's an Eaton, good clutch. Have done tons of them with good success, likely more of them than all of the Aisin clutches combined.

 

[Kernal]

Any more info on the spring adjustment procedure?

 

[landtank]

Have done tons of them with good success, likely more of them than all of the Aisin clutches combined.

I seriously doubt this.

 

[e9999]

It's an Eaton, good clutch. Have done tons of them with good success, likely more of them than all of the Aisin clutches combined.

hoping you're talking about mine.
What are the distinctive ID signs of an Eaton?

(I did see a pic of an alleged Eaton and the knobs and gaps on the fins looked different. Are there more than one type?)

 

[Kernal]

e9999: not the expert but here's some photos of an original Eaton fan clutch from my early 96 model FZJ-80 (the four torx screws that hold the halves together have been removed):

 

[Tools R Us]

I seriously doubt this.

I don't keep track, but it sounds like you do, so how many Eaton vs Aisin clutches have I done? This week Aisin is winning, but most are not off of 80's, the Sequoia, 100, 40, etc, clutch count is winning.

 

[Tools R Us]

hoping you're talking about mine.
What are the distinctive ID signs of an Eaton?

(I did see a pic of an alleged Eaton and the knobs and gaps on the fins looked different. Are there more than one type?)

The look, have seen a few, so recognize them. I have only seen one type.