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

[Cattledog]

Cattledog, I just drained it. I'm a big beleiver in no chemicals unless absolutely needed.

Land Tank, with that additude how do you expect chemist's like me to survive!

 

[Tools R Us]

A proper test IMO, needs nothing to bend other than the radiator fan blades. A proper test needs only two components, clutch lockup and redline.

So, now your saying that chassis flex, mount flex, body flex, etc. have no effect on fan to shroud/radiator clearance?

...I just don't recommend the 10k cst in lockup and 5000rpm engine speeds...

And now the ever moving speed of death and destruction up to 5000rpm? It started at what, 4000+ then, 4500, then 4800, now 5000?

The main point being that the foam blocks, placed at the closest spot to the face of the fan, that are as close as I can measure about .5" from the fan and haven't been hit. Showing that my fan flexes less than .5". I have no idea how you flexed your fan 3.5" when it less than 2" from the radiator face stock, but my truck doesn't exhibit this behavior. I ran it again and observed the same, by my old feeble eye it looks to be less than 1/4", and would post the same 3/8" to be conservative and allow for eye ball measurement error.

My truck isn't a race car, it's a daily driver, delivery truck for my business and a weekend wheeler. In it wheeling mode it's frequently miles away from the "pits" or pretty much any type of service, so I prefer simple solutions, using as many stock parts as possible. This mod delivers additional cooling capacity, stable temps and great underhood airflow, without the need for carbon fiber hood scoops, air tunnels or electric fans. The belt driven fan isn't trick or exotic, but is a simple, effective, proven reliable over the last hundred years or so design and that's what I am looking for on a wheeler.

Knowing Toyota, I will bet that they are aware that a failure mode of a fan clutch is bearing failure, locking up the clutch and bet that they tested for operation in that mode. IIHO the blue hub and it's matching fan are quality parts engineered to work with the truck, it's unfortunate that they put thinner fluid in it than I "need", but that's simple and inexpensive to correct.

 

[Tools R Us]

Cattledog, I just drained it. I'm a big beleiver in no chemicals unless absolutely needed. I got the same OFNA oil you did only drove to Nashua to get it .

The housing also rotated very easy once the oil was out.

I agree on the just let it drain theory, for the drive hub side. I used solvent and tried blowing it out, that made a big mess, letting it sit could still smell the solvent and didn't want to contaminate the new fluid. So I put it in the oven at 180F after it warmed the solvent evaporated. Next time I will just stand it on edge and allow it to drain, what little is left in there probably isn't going to cause a problem. The reservoir side with the valve plate out is no problem to clean.

 

[SUMOTOY]

So, now your saying that chassis flex, mount flex, body flex, etc. have no effect on fan to shroud/radiator clearance?

TRU, read the posts from 8-10-05 and the thread I started on 2-10-06. I have said many times that the radiator doesn't flex, but all else does. I also have measurements that appear to indicate that the clearances under lockup at high rpm are tight, with or without a shroud, with or without a SC spacer. I hope it's clear. If not, please reread the original posts with measures, it's in this thread too.

And now the ever moving speed of death and destruction up to 5000rpm? It started at what, 4000+ then, 4500, then 4800, now 5000?

Again, to be clear, my data is 6 incidents. The very first I logged was above 4500rpm. I know this, because (again read the Steamboat reports) I drove for 4 hours on the track shifting at 4500 without incident. Somewhere shy of 5000 I had incident number two. Then I trimmed a couple fan blades, which one would reasonably conclude raised the rpm level of the engine before interference. Which it did, since my next incident was just over 5000rpm. My last incident with only 4 intact blades, was just shy of redline with no fan shroud.

Failure became significant for me with the SC spacer and 10kcst fluid at 4500 all else being equal (full stock fan blades, shroud installed and intact). The subsequent 'tests' indicate that reducing the performance of the blade shifted the rpm level up. Sounds reasonable? All that said, when I took the measures of the radiator bore diameter it showed significant flex and deformation of the blades (look at the data man!). Just looking at measures of failure I posted, I concluded that removing the spacer didn't appear to leave a lot of room on a non SC truck. NOW, add chassi flex, mount flex and body flex.

The main point being that the foam blocks, placed at the closest spot to the face of the fan, that are as close as I can measure about .5" from the fan and haven't been hit. Showing that my fan flexes less than .5". I have no idea how you flexed your fan 3.5" when it less than 2" from the radiator face stock, but my truck doesn't exhibit this behavior. I ran it again and observed the same, by my old feeble eye it looks to be less than 1/4", and would post the same 3/8" to be conservative and allow for eye ball measurement error.

The nice thing about my failure TRU, is there is no 'eyeball' measure, it's perfectly scribed circle in my radiator core. Again, if you read the threads, you would understand that a fan can flex more than interference. I measured core damage .5in into my radiator.

My only point is that a truck should be able to hit redline at clutch lockup without causing catastrophic failure. If not, warn me of it, or change redline. I've driven hundreds of cars and trucks to redline, never once thinking I was going to auger the radiator core. I do know that I also added 10k cst fluid to accompiany my specific failure. A data point of *failure* for others thinking it's a great mod.

I'm glad with your runs to 4800 rpm you didn't have failure with 10k fluid.

I really hope we can set our sights a bit more on some type of replicable data, not eyeball measurements and glove tests. I'm happy to put mine up for scrutiny, and give as much followup information as I can. Denial that it's a possible failure issue, seems to contradict my data.

Scott Justusson
QSHIPQ Performance Tuning

 

[landtank]

It looks to me that we have 1 truck on 10K with issues and 1 truck on 10K without issues. I'd say it's a draw!

There could be any number of reasons for either truck to respond differently to the 10K oil. To say that a single positive or negative response to the 10K oil is indicative of all trucks is a little premature. I would say however that using 10K oil at this point would seem to be borderline on the high side of viscocity and anyone selecting this grade should be aware of the potential issues and except those risks.

 

[cruiserdan]

<snip> and 1 truck on 10K without issues. I'd say it's a draw!

Make that two please.

 

[LandCruiserPhil]

Make that two please.

I come up with 3 with no problems

Tools
Medtro
cruiserdan

I with a lot of problems

SUMOTOY

 

[landtank]

I guess the silent majority has decided to join in.

 

[SUMOTOY]

I come up with 3 with no problems

Tools
Medtro
cruiserdan

I with a lot of problems

SUMOTOY

I enjoy the thought of being a special case, but I know I'm not. 1 with a lot of failure experience with this mod. "1 with a lot of problems" convincing my radiator repair shop in the boonies of CO to stay open past 6 to fix the carnage of the failure experience. Thank goodness for...

SJ

 

[Tools R Us]

I've just got back from a run with the truck with 5K oil in it and I'd have to say this is probably the minimum viscocity that you should have in your clutches.

Another point was when I drained the old oil it had darkened comsiderably. I don't know what this means, just an observation. The new fill went in clear and I'll check it after some miles.

I'll be changing the initial posts to reflect the oil change.

Good to hear, did you change the valve setting? It's looking like 6000-8000 cst is going to be the sweet spot.

Was the oil you added golden or clear? One the engineers I talked to said that there are two mechanisms that will cause darkening. All of it is clear when made, if exposed to sunlight, UV it will darken overtime, this has little or no effect on it's performance. If aggressively over sheared or overheated it will darken and will permanently reduce it's performance.

 

[cruiserdan]

I think maybe 10,000 for blown trucks that are running the smaller blade.


So far, so great, for mine anyway.

 

[landtank]

The oil I added was clear and it diluted the color some from the original oil but after that towing trip it darkened back up to where it was when I first opened it.

I'm planning on going with Toyota oil in the 6K range. I think a drain and fill will just be 2 tubes, but I want to confirm this before updating the first posts.

I didn't change the timing and don't plan on it. I lke the idea of a little more airflow at idle on those hot days and I don't think it will really impact the MPG. On my return trip I actually got better MPG with the clutch more advanced. I imagine it's from running cooler and the engine performing better.

 

[landtank]

I think maybe 10,000 for blown trucks that are running the smaller blade.

I thought that as well.

I think the big thing on the fan contact is staying ahead of the demand. As long as the engine is staying close to the normal temp range you'll never lockup the clutch to where a downshift might send the fan into the rad.

If you did see where the engine temp would climb say in a loaded hill climb I think a slight advancement of the timing would take care of it.

 

[cruiserdan]

One does not want to advance the timing in a blown motor, they are on the edge of knocking as-is.

 

[Tools R Us]

TRU, read the posts from 8-10-05 and the thread I started on 2-10-06. I have said many times that the radiator doesn't flex, but all else does. I also have measurements that appear to indicate that the clearances under lockup at high rpm are tight, with or without a shroud, with or without a SC spacer. I hope it's clear. If not, please reread the original posts with measures, it's in this thread too.

I have read most of you "data" and have no need to reread it. In a dynamic environment things flex and move, when offroad frames flex, body mounts flex, the body flexes, motor mounts flex, etc. The radiator is mounted to a different structure from the fan and the flex can and will change the available clearance.

The nice thing about my failure TRU, is there is no 'eyeball' measure, it's perfectly scribed circle in my radiator core. Again, if you read the threads, you would understand that a fan can flex more than interference. I measured core damage .5in into my radiator.

I am very happy for you having that nice "data". I can clamp a fan in the vice, grab a blade with a wrench and get more flex than that, but what does mechanical flexing have to do with a discussion on aerodynamic load flexing to determine clearance?

 

[cruiserdan]

Cage-match

 

[sleeoffroad]

Hey, I haven't posted anything in this thread, so I thought I should add something I think I figured out all my problems with fans hitting the shroud etc etc (on the ShortBus). I recently removed my tranny crossmember and installed a new one. It looked a little bent. Well, it was about 1.5" bent upwards. That meant the front of my engine was titled down and that is why I never had problems in the beginning with the fan hitting and only later on.

So, leave me out of this.

 

[cruiserdan]

So, leave me out of this.

LOL!....



You get to be the Ref....

 

[landtank]

One does not want to advance the timing in a blown motor, they are on the edge of knocking as-is.

Dan, I was talking about the fan clutch, I ment advancing the timing of the fan clutch by rotating the control plate. That way the clutch comes on sooner which helps it to stay ahead of the cooling demand.

 

[cruiserdan]

Dan, I was talking about the fan clutch, I ment advancing the timing of the fan clutch by rotating the control plate. That way the clutch comes on sooner which helps it to stay ahead of the cooling demand.