Blue fan clutch mod...Thread has gone to hell, read at your own risk (4 Viewers)

[cool breeze]

While i decided to go the economical route and reuse my old clutch and just change out the oil with some 7k. I found some kyosho brand 7k oil in town, kinda hard to get a hold of.

So i just opened it up and found nice deep amber colored oil in it. Also the on the inside on both sides of the plate surface there is some nice heat stress cracking. Now really thinking about going new all together and not even bothering with this one. Has anyone else seen this cracking before?

 

[Tools R Us]

While i decided to go the economical route and reuse my old clutch and just change out the oil with some 7k. I found some kyosho brand 7k oil in town, kinda hard to get a hold of.

So i just opened it up and found nice deep amber colored oil in it. Also the on the inside on both sides of the plate surface there is some nice heat stress cracking. Now really thinking about going new all together and not even bothering with this one. Has anyone else seen this cracking before?

Some pix would help? I have never seen any cracks, have seen some casting marks that look like cracks. What brand/type of clutch? In Texas I would think about thicker fluid, like 10K+.

 

[cool breeze]

I thought about that but its not that hot here, only a balmy 100 degrees. But really i didnt want to hinder the performance if i go someplace colder for a trip. A buddy here put 6k and he's thinking of upping to 7k and another put 10k and i could hear some off idle knock real bad on his. I remember somewhere in this beast of a thread something about too thinck of an oil not allowing for proper running temps.?.

 

[cool breeze]

and another..

 

[Tools R Us]

If your referring to the "crack" looking lines close to the center of the hub, those are casting "webs". Normal lines from the casting process, nothing to worry about.

I thought about that but its not that hot here, only a balmy 100 degrees. But really i didnt want to hinder the performance if i go someplace colder for a trip. A buddy here put 6k and he's thinking of upping to 7k and another put 10k and i could hear some off idle knock real bad on his. I remember somewhere in this beast of a thread something about too thinck of an oil not allowing for proper running temps.?.

I spent some time in the snow on the way to CM08 with zero issue. The thermostat valve is still active, so the clutch will still freewheel when not needed. The off idle knock can be caused by several things, but I cant think of a reason that it would be caused by thicker clutch fluid. On mine it was greatly reduced, due to better cooling when wheeling at low speeds.

 

[Tools R Us]

Is that clutch a blue hub? It looks like an early style, if so it's the only other one that I have seen. They are good clutches, have more shearing area and a bigger reservoir than the newer style.

 

[cool breeze]

It has a black hub and is off my 94 which a had very good maint. history by the first owner. I thought it might be an aftermarket like i've read about but it has the aisin stamp and the cast thermo holder like the one you posted. I thought it was the same one, how is it different?
It does not look like any casting marks i have seen, it just looks disturbing to me.

 

[Tools R Us]

It has a black hub and is off my 94 which a had very good maint. history by the first owner. I thought it might be an aftermarket like i've read about but it has the aisin stamp and the cast thermo holder like the one you posted. I thought it was the same one, how is it different?

From that pic it looks like my "early" blue hub, shoot a pic of the other half?

It does not look like any casting marks i have seen, it just looks disturbing to me.

It's hard to tell for sure from your pic, but they look normal to me. If they were cracks, they would extend across the machined part, in the pic it doesn't look that way. Maybe post a closer crop of the center area.

 

[cool breeze]

Here are some more...

So is this one worth tweaking and re-using like the blue. I have already gone this far so im just going to try it out. THe question is how to fill with new oil? Im using hobby shop oil so i cant make it "so many tubes of toyota stuff." The bottle i used is a 40cc plus a little more of another but i cant see the underside of the inlet hole like Landtanks pic.

I guess the question at hand is, If i just fill it up to the top lip of the plate on the hub side, is that too much?

 

[clarkrw3]

So as many of you know I have had a problem with water temps in the summers when it is very hot outside like today 106deg. I recently got a scangauge II and thought I would finally try and get to the bottom of this problem.

Things we have tried.

Changed the rad. to brass unit
changed the thermostat
changed coolant flushed twice
changed fan hub to blue unit
changed fluid in the blue hub twice to thicker fluid
Made foam and shroud were in correct places around radiator


Info from today

outside temp 106-110
intake charge 128-138 while driving
intake charge 145-155 while in drive through at In and Out
water temp on freeway 191-195
water temp at stop lights 198-202
water temp at InO 198-211

at rest with foot on brake RPM's are just under 700
in park they rise to just under 900

If I put it in park and rev to 1500-2000rpm the temp goes back down to 195-198 in a min or two


So I have come up with a couple of things....It is safe to assume that I am not getting enough airflow through the rad during stops! Is my idel set too low? Do I just need to hook up the pusher fan I already have? Do I need a new water pump? (I doubt) Do I need even thicker fluid in the fan clutch? Do I scrap the truck and try again with another truck?? Do I keep doing the same thing and leave my truck in the garage for the summer months??

 

[franku]

So as many of you know I have had a problem with water temps in the summers when it is very hot outside like today 106deg. I recently got a scangauge II and thought I would finally try and get to the bottom of this problem.

Things we have tried.

Changed the rad. to brass unit
changed the thermostat
changed coolant flushed twice
changed fan hub to blue unit
changed fluid in the blue hub twice to thicker fluid
Made foam and shroud were in correct places around radiator


Info from today

outside temp 106-110
intake charge 128-138 while driving
intake charge 145-155 while in drive through at In and Out
water temp on freeway 191-195
water temp at stop lights 198-202
water temp at InO 198-211

at rest with foot on brake RPM's are just under 700
in park they rise to just under 900

If I put it in park and rev to 1500-2000rpm the temp goes back down to 195-198 in a min or two


So I have come up with a couple of things....It is safe to assume that I am not getting enough airflow through the rad during stops! Is my idel set too low? Do I just need to hook up the pusher fan I already have? Do I need a new water pump? (I doubt) Do I need even thicker fluid in the fan clutch? Do I scrap the truck and try again with another truck?? Do I keep doing the same thing and leave my truck in the garage for the summer months??

In terms of your water temp - I don't thnk there is a big problem - will it go over 211?

 

[clarkrw3]

I don't know....if past experience is anything I am pretty sure it will. I got my food, and had the wife and kids in the car so didn't want to push it.

 

[Tools R Us]

A “new” clutch to look out for. We did HJ60’s fan clutch on his ‘94 FZJ80. It has a black hub, but full cooling fins like an Aisin and still had some drive, so we pulled it instead of ordering a new blue hub. Sure enough it is an Aisin, with a black painted hub, haven't seen this before. Have no history on it, so no idea where it came from, how old it is, etc.

 

[Tools R Us]

Inside the design looks the same as my early blue hub. Larger reservoir, boot type “3 speed” valve and extra shearing area/grooves. These are the most powerful clutches that I have seen and this one didn’t disappoint. We put 13,000 fluid and it moves major air. If you have one of these clutches, hang onto it or send it to someone who can use it. They are great clutches and probably no longer available.

Lately I have saved and measured the fluid drained from two blue hubs (40 & 42ml) and this black hub 51ml. This number is what could be removed from the pan, there was some lost in rags, residue in the pan, clutch, etc. I have been putting 50ml in the new type and we put 55ml in HJ60’s black hub, my guess is the older design clutch could hold 60ml+ and still cycle correctly.

 

[Beowulf]

Kevin,
Other than the silicone fluid, what would possibly wear out in our blue hub or this black hub AISIN clutch?

Do the temp springs go bad?

-B-

 

[turbocruiser]

Kevin,
Other than the silicone fluid, what would possibly wear out in our blue hub or this black hub AISIN clutch?

Do the temp springs go bad?

-B-

I'm not Kevin (but I did stay at a Holiday Inn a few years ago haha) but as far as I know the only thing that wears out with the springs is when the springs corrode or get crimped or get loosened by something. I may have remembered this reversed but I thought that the bimetal configuration really just relies on the expansion and contraction rates of the two metals and that as long as corrosion or crimping or loosening of the spring isn't a problem the spring metals will both "age together" and "work together". HTH.

 

[Cruiserdrew]

I thought it was the little shaft that the spring turns that gets corroded in it's bore and keeps the clutch from turning "on".

Bottom line-it's a good idea to change it at 100k miles and adding the higher viscosity fluid is good too. I've done all that and a new radiator and it runs as cool as you might want.

 

[Tools R Us]

Kevin,
Other than the silicone fluid, what would possibly wear out in our blue hub or this black hub AISIN clutch?

Do the temp springs go bad?

-B-

The temp springs don't just go bad, but there are some failure modes. They are bimetallic, in rust prone areas that can ruin them. Also the rod through the housing can be stuck by corrosion. In our areas this is very rare and the valve assembly pretty much works forever.

Another failure that I have seen is the bearing going bad. In a few cases have seen them locked up. But most of the time the first indicator is, the fluid is black. The tolerances in the clutch are very close, so relatively slight play in the bearing allows contact between the alloy parts, making a black dust in the fluid.

The most common failure is leakage. It's easy to spot, the clutch and most of the time fan blades are gooey with the fluid. Other than the o-ring the fluid doesn't sit on the seals, there is little/no pressure, so little chance for failure. Some slight seepage at the seal is normal, a small dirty ring at the seal no issue.

The above failures are most common on aftermarket clutches, they are mostly smaller, have less cooling area/fins, so run hotter, fail more often. The factory clutches are much better constructed and mechanical failures are rare. The only "contact" parts are the hub seal and bearing, both are lubed by the fluid and silicone fluid is a fantastic lube.

I recently did one on a ~200K mi, '83 Mini, don't know the history on it, but it was ether a factory or from that era dealer replacement. It was in great condition, cleaned, refilled with 10K and it works better than new.

My thoughts are: The newer clutch designs appear to be more compromised towards fuel economy/low noise, rather than ultimate cooling/life. This can be somewhat overcome by tuning with thicker fluid, but due to the smaller reservoir, reduced shearing area fluid life maybe shorter. Mechanical failure is rare, by far the most common is fluid failure, so by changing the fluid every 4-5 years, I see little reason why a good Aisin clutch wouldn't last the life of the truck.

 

[Beowulf]

... so by changing the fluid every 4-5 years, I see little reason why a good Aisin clutch wouldn't last the life of the truck.

Thanks Kevin. Your answer addresses exactly what I was asking.
-B-

 

[theferg]

black hub clutch

After reading about the black hub clutch I was curious as to what I pulled off my '94 last year when I went to a blue hub clutch. Went out and found the box I put the old one in and opened her up and found this: