Blue fan clutch mod...Thread has gone to hell, read at your own risk (2 Viewers)

[SUMOTOY]

I agree that most of the time if the fan hits the shroud, it's going to get into the radiator, most of the time the lower flange, where the lower tank attaches. The reason I brought up the lower shroud first contact wasn't to imply that it provided protection, only that I thought it was a good spot to attach the foam test blocks.

Yep, the fan ring is an old racer's trick, it's harder to implement on the 80 due to the raised lower tank. My point is that the foam blocks are still there, unmolested, so I don't see the need? Going to run it hard this weekend and see how it goes.

Bring radiator stop leak, it saved me 2 of the 8 times. A very faint ticking noise at high rpm would be my monday morning quarterback reflection. It might also be worthy to note that fan flex and *motor* flex combined are the variables mentioned in that thread.
Hope it works

SJ

 

[cruiserdan]

Also a body lift.

 

[SUMOTOY]

Also a body lift.

That '05 thread seems to contradict this one. Without question radiator fan interference is a problem and has been for some time, I appear to be in good company.

IDoug deserves the 'predict the future award' in post 13, I hope he puts his feet up on his desk more often... I've been working on adapting that solution for over a week. It might actually resolve a lot of this debate. My research is done, the parts app a bit trickier

Scott Justusson
94 Supercharged

 

[Tools R Us]

Bring radiator stop leak, it saved me 2 of the 8 times. A very faint ticking noise at high rpm would be my monday morning quarterback reflection. It might also be worthy to note that fan flex and *motor* flex combined are the variables mentioned in that thread.
Hope it works

SJ

That's why the trail test is important, everything is dynamic on the trail. The frame, body, mounts, fan all flex with suspension flex and impact loads, closing and/or opening clearances in a hurry. A road test will only give pretty much static data, taking it out and dropping off a few ledges, flexing it up and bumping some rock will tell the real story.

 

[cruiserdan]

That '05 thread seems to contradict this one.

https://forum.ih8mud.com/showthread.php?t=55521

Read post #70.

 

[SUMOTOY]

https://forum.ih8mud.com/showthread.php?t=55521

Read post #70.

Scamper's #69 is more interesting. If you block airflow behind the blades, you create more lift. Could it be that the high pressure zone directly behind the fan blades helps move them forward? I know this, when munching my fan blades, vehicle speed was under 40 (first gear redline). It will happen less as speed increases, because there is more pressure in the shroud caused by ram air.

Lots of interesting stuff in that thread. Body lift isn't the only cause for engine flex, any engine that isn't rigidly mounted will change the clearances between fan and radiator, because the radiator is mounted to the body, not the motor. That indicates to me that strictly isolating fan flex in engine rpm vs lockup, doesn't account for engine movement as rpm increases, body lift or stock.

SJ

 

[cruiserdan]

Body lift does not cause engine flex. However it could move things around in a manner where the flexing engine could hit something that would not normally be in the way. That is why I mentioned it.

 

[Tools R Us]

I don't have time to reread that thread today, but IIRC most all of the fan interference problems have been on modified trucks. From my limited testing it doesn't look to be a problem with a stock configuration, crossing fingers.

 

[Cattledog]

I pulled apart my newer blue clutch tonight. I had two screws siezed.

The first screw was on the outside of the housing. One of the screws that are removed to seperate the clutch assembly. A drill and ez-out worked well. I will post the thread, size and style later. I will be converting the bolts to socket panhead style.

The second screw was one of the adjustment screws in the clutch. That one sucked. Drilled it and then broke the ez-out inside of the screw. In the end I used the dremel tool to cut the head off the screw. The pitch is course/0.7 mm, Lenght 8 mm, head 9 mm. I will be replacing the screw with the following McMaster-Carr part

Part # 92855A408
Discription
Metric 18-8 Ss Low Head Socket Cap Screw M4 Size, 8 mm Length, .7 mm Pitch

The smaller toyota screws have always been too soft IMO. They tend to strip or sieze about 80% of the time. Anyone modding the clutch might want to have these screws around for reinstall.

Good luck!

 

[Tools R Us]

Phillips Tips;

I hate the damn things too, but have to work with them everyday. Having good screwdrivers makes a world of difference, for the #3's on the clutch an impact driver would probably work well. I knock them out with an IR2115 impact and a #3 socket. With a bit or screwdriver I always tap, seat it into the screw with a hammer then remove it.

If it strips this is the first procedure that I try;

Look at this picture, (the most messed up one I could find on short notice) the phillips shape is deformed, pushing metal up out of it.

A couple of good hammer blows drives that metal back down and the vibration from the hammer blows somewhat loosens the screw.

Now take a good solid screwdriver and drive it into the slot, I try to do it in two blows, the first one just to get it started, check the alignment, then one solid blow to seat it. This will broach a new phillips shape that perfectly matches your screwdriver and loosen the screw by driving it down and slightly deforming the backside of the screw head.

I pulled the screwdriver out to show the new hole, never do this when removing. As soon as the screwdriver is set, turn the screw out, trying not to apply any side force only turning.

I have or do own most good brands and my favorite screwdriver is Whia, they have precision shaped blades and can take a beating. For this type of work a through handle shank type is best, otherwise your beating on a plastic handle that absorbs part of the energy.

Some of the sanders that I work on have a dozen or more soft, tight phillips screws and this method works about 95% of the time, sure beats drilling and tapping!

 

[landtank]

Excelent tip Tools

 

[MikeB]

Kevin -

What do you think about replacing Phillips screws with a different drive design, like Allen or Torx? The cam-out action in Phillips makes it hard to apply much torque.

 

[Tools R Us]

Kevin -

What do you think about replacing Phillips screws with a different drive design, like Allen or Torx? The cam-out action in Phillips makes it hard to apply much torque.

I agree with it, I prefer Torx.

 

[Cattledog]

Nice tip! I will try that next time.

 

[landtank]

One thing to remember about Japanese Philips head screws, they aren't built the same as the rest of the world. The socket in the screw has a different bottom on it and technically you should be using a Japanese screw driver on them that has the mating tipped Philips to match.

This was a big problem when working on Photocopiers. They had these screws all over the place and using a standard Philips would strip them out if they were a little tight in there.

Check here Japanese screwdriver

 

[SUMOTOY]

One thing to remember about Japanese Philips head screws, they aren't built the same as the rest of the world. The socket in the screw has a different bottom on it and technically you should be using a Japanese screw driver on them that has the mating tipped Philips to match.

This was a big problem when working on Photocopiers. They had these screws all over the place and using a standard Philips would strip them out if they were a little tight in there.

Check here Japanese screwdriver

Good call Rick! IIRC all Snap-on Phillips screwdrivers conform to JIS standard 4633B-3/1991. Read: Don't ask for a "Japanese" Phillips head on the Snap-on truck... The problem with US screwdrivers is they tend to have too sharp a point. This is usually only found in #1, and sometimes #2 Phillips. 4633B has to do with the tighter tolerance in manufacture of the tip land area.


A good reason to visit the snap-on truck and spend exponentially more money for the logo.

Scott Justusson

 

[Photoman]

Very sorry for the hijack Rick.

Along with beating the heads down on bad screws like Kevin said, I will sometimes touch up the tip of the screwdriver to get maximum grip. Phillips tips tend to get rounded with use, so it is possible to get nice sharp biting edges again by filing them or sanding them using sandpaper on a piece of steel etc. The tips of the better screwdrivers are hardened, but I have done this for many years and many times it is enough to save a lot of work.
</hijack>

Bill

 

[Beowulf]

One thing to remember about Japanese Philips head screws, they aren't built the same as the rest of the world.

This makes the SECOND new thing that I've learned this morning and explains why my that darn screw on my starter gave me fits and cost a small fortune to get removed.

Wish I'd known this a long time ago. Anyone know if those German Wiha screwdrivers meet the JIS standard?

-B-

 

[landtank]

According to that link US and Europe are the same, It's Japan that is out on it's own.

Photoman, no highjack as far as I'm concerned, we're still talking about the fan clutch mod and having the right tools to avoid issues or ways to recover from them is part of the game.

 

[Cattledog]

Hey guys,

I was over Landtank's house this morning. He set the clutch to 95 degrees per his instruction. We also topped off the fluid in the clutch with some toyota 3000 wt fluid and some of the hobby shop's 3000 wt silicon fluid. Thanks for the time Landtank.

Well the results are in, The cooling is better, but not as good as I hoped. The truck is running around 205 degrees instead of 210 to 215 without the mod with the AC on and no recirc. I still have the original Aluminum 2 core radiator. The fan is engaging at 205 degrees. I can here and feel the air flow. I may try the 5000 wt oil from the hobby shop. First, I will try a char test on the hobby shops oil. Basicly heat the crap out of it in air and look for varnishing. Silicon oil should not varnish but should thicken.

I am wondering how the hobby shop's oil is measured and if it is comparable to the toyota fluid. Viscosity can be measured in different ways depending on the application (Kinematic Vs Dynamic). The two fluids were completely miscible.


Thanks for all of the help.