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

[landtank]

Sumotoy and Toolsrus, this thread is discussing the fan clutch and not the FAN itself. Maybe you two could take this back over to that ABC thread.

 

[landtank]

I'm not against the higher oil, I would just like to fully investigate what has been done so far so we can better gauge the effect of the thicker oil.

If there is no ill effects such as a loss in MPG or fan over run then why not. But if there is no advantage the why.

 

[SUMOTOY]

I'm not against the higher oil, I would just like to fully investigate what has been done so far so we can better gauge the effect of the thicker oil.

If there is no ill effects such as a loss in MPG or fan over run then why not. But if there is no advantage the why.

I ran almost 3 tubes of 10,000 in my stocker. I experience the fan blade flex at steamboat with the shroud installed above 5000rpm.

I believe that a locked up thermo with thicker oil will cause higher fan speeds at higher rpm's. My concern isn't at all low speed activation. A thicker oil should come on faster since it's high viscisity, it will lockup quicker. It will also stay locked longer when under activation.

This is a phenom that should only manifest itself under maximum load. High rpm + locked thermo. Add in .75in closer to the radiator, I'd be very worried about fan blade flex with the SC and higher rpm's.

My issue with messing around with fluid changes, is that you are just shifting fan performance. They are directly related. Although Dan has found that the thermo is the same to OZ vs US, it might be interesting to see what the blade app is.

VC's with viscosity changes will affect rpm lockup. That could be good, but I believe there can be circumstances where it's not.

Scott Justusson

 

[SUMOTOY]

Sumotoy and Toolsrus, this thread is discussing the fan clutch and not the FAN itself. Maybe you two could take this back over to that ABC thread.

TRU:
I agree. If you wish to delete and repost that over to ABC's, I'll be happy to address it there.

Scott Justusson

 

[landtank]

I ran almost 3 tubes of 10,000 in my stocker. I experience the fan blade flex at steamboat with the shroud installed above 5000rpm. /QUOTE]


This is a major concern of mine. Correct me but steam boat was during the cold weather.

There should have been no lock up at all in these temps, the fact that you saw some flex at all is evident that either the fill was too high or the viscocity too thick.

 

[SUMOTOY]

I ran almost 3 tubes of 10,000 in my stocker. I experience the fan blade flex at steamboat with the shroud installed above 5000rpm. /QUOTE]


This is a major concern of mine. Correct me but steam boat was during the cold weather.

There should have been no lock up at all in these temps, the fact that you saw some flex at all is evident that either the fill was too high or the viscocity too thick.

LT, cold weather yes, but lockup a lot. 7300 feet reduces radiator efficiency, and I was running that truck at 8 to 10/10ths all the time. Remember this was a track event. I know trans temps were unreal, and caused me the most concern. I assure you, it was hot in the engine bay.

I filled what I believe was specification, and IIRC, it was pretty much what I took out in terms of level. I let that puppy sit to drain for a few days prior to doing fluid (I stood it up in a noodle strainer over a drain bucket)

I believe thicker fluid under lockup is a problem. I certainly confirmed that fan blades flex to interference above 5000rpm.

I know after the 6th or so radiator pull, that below 4700, I had no catastrophic fan blade flex. That extra 1000rpm got me every time (including a race I had with a LX470 hotshot back in chicago).

Currently I have only 2 full sized blades on a brand new fan, and I don't run to redline because I don't trust the clutch/fan arrangement anymore. I use my work truck daily, it running everyday is part of what makes it my work truck.

I'm concerned about it Rick, because I have the carnage to prove that a locked up VC thermo *can* be a problem at high rpm. I believe you need to have lockup (high heat) and high rpm, but that's the combo that got me every time. I'm pretty convinced too, that the .75in supercharger spacer difference probably saves a lot of folks. But look at my measures, anyone under the same conditions is gettting close to skimming the radiator, and is probably already ticking the fan shroud at the bottom.

Scott Justusson

 

[semlin]

I guess Sumotoy gives us a data point. fan flex is still adequate at 4700 rpm at 7300 feet of altitude in a supercharged truck under racing conditions with a fan clutch filled with 10,000 cst oil. that should give the rest of us mortals confidence that we can safely fill it with 10,000 cst under all normal driving conditions if we decide that steo will yield any useful benefits. that last "if" remains a big one and I'll wait on the data for that.

 

[Tools R Us]

Played with mine a little more last night. With the fan roaring revved it to 4500 rpm, sighting across the backside of the fan and shroud edge I get about 1/4 - 3/8" of fan flex. Also hit 5000 rpm twice on the way home with no drama. Going wheeling this weekend, the highway trip includes two big hill pulls and would prefer to bang it closer to home if it was going to happen, but it looks good.

This 10000 cst setup pulls an absolute HUGE amount of air, for most of the country it's probably overkill. Running at 2500 rpm it's a serious wind tunnel under the hood, dumping loads of warm air out the wheel wells and from under the truck. Stepping out of the drivers seat I can feel the wind from under the truck on my legs.

The stock blue hub comes close or works for most, so for most of the country a blend of fluids would probably work best. In the cooler areas 5000-6000 cst would give a nice margin of added cooling capacity and in the hottest areas, with towing, heavy wheeling, etc. the 7000-10000 cst range.

These are early observations and I haven't had the pleasure of being stuck in a hot traffic jam to see how the A/C performs in those conditions, but so far the vent temps look promising. Thinking of changing the fluid to 8000 cst on Rob's truck and removing the "Band-Aid fix" electric pusher or pulling the fuse and abandoning in place for possible emergency use?

 

[Beowulf]

I guess Sumotoy gives us a data point. fan flex is still adequate at 4700 rpm at 7300 feet of altitude in a supercharged truck under racing conditions with a fan clutch filled with 10,000 cst oil. that should give the rest of us mortals confidence that we can safely fill it with 10,000 cst under all normal driving conditions if we decide that steo will yield any useful benefits. that last "if" remains a big one and I'll wait on the data for that.

Add to this data point that his S/C fan is .75" closer to the radiator than stock fans.

-B-

 

[SUMOTOY]

Played with mine a little more last night. With the fan roaring revved it to 4500 rpm, sighting across the backside of the fan and shroud edge I get about 1/4 - 3/8" of fan flex. Also hit 5000 rpm twice on the way home with no drama. Going wheeling this weekend, the highway trip includes two big hill pulls and would prefer to bang it closer to home if it was going to happen, but it looks good.

This 10000 cst setup pulls an absolute HUGE amount of air, for most of the country it's probably overkill. Running at 2500 rpm it's a serious wind tunnel under the hood, dumping loads of warm air out the wheel wells and from under the truck. Stepping out of the drivers seat I can feel the wind from under the truck on my legs.

The stock blue hub comes close or works for most, so for most of the country a blend of fluids would probably work best. In the cooler areas 5000-6000 cst would give a nice margin of added cooling capacity and in the hottest areas, with towing, heavy wheeling, etc. the 7000-10000 cst range.

These are early observations and I haven't had the pleasure of being stuck in a hot traffic jam to see how the A/C performs in those conditions, but so far the vent temps look promising. Thinking of changing the fluid to 8000 cst on Rob's truck and removing the "Band-Aid fix" electric pusher or pulling the fuse and abandoning in place for possible emergency use?

TRU
Your fan flex is not valid. You have changed the low pressure zone to behind the fan to be higher. You need to close the hood.

The test I designed for 'flex' was to put varying thicknesses of foam board at the lowest part of the radiator shroud. With the .75in fans spacer and SC, I had a lot of pink confetti at 5000rpm. However, the most concerning thing to me was the difference in fan blade diameter (rest vs tip scribe in radiator). These fans flex, and big time.

Agree that blending of fluids might be the trick. I would be very careful of redline and lockup, I don't need to speculate, only conclude.

Scott Justusson

 

[SUMOTOY]

I guess Sumotoy gives us a data point. fan flex is still adequate at 4700 rpm at 7300 feet of altitude in a supercharged truck under racing conditions with a fan clutch filled with 10,000 cst oil. that should give the rest of us mortals confidence that we can safely fill it with 10,000 cst under all normal driving conditions if we decide that steo will yield any useful benefits. that last "if" remains a big one and I'll wait on the data for that.

Be careful here. when I hit 5000rpm back in chicago, I already had clipped all but 4 of the fan blades. I clipped two more after that. That was just a engaged high speed impromptu traffic light race. A better test would be the foam board test. Anyone that thinks the .75in SC spacer is a safety margin, the foam board might test get you thinking. I concluded the only thing from stopping more flex was the amount of radiator core braking....

What I don't recommend is becoming a god at radiator removal, being a mere mortal at that *is* the key. 6-8 times, most of those at 15 degrees, 1 at -10

SJ

 

[Tools R Us]

TRU
Your fan flex is not valid. You have changed the low pressure zone to behind the fan to be higher. You need to close the hood.

The test I designed for 'flex' was to put varying thicknesses of foam board at the lowest part of the radiator shroud. With the .75in fans spacer and SC, I had a lot of pink confetti at 5000rpm. However, the most concerning thing to me was the difference in fan blade diameter (rest vs tip scribe in radiator). These fans flex, and big time.

Agree that blending of fluids might be the trick. I would be very careful of redline and lockup, I don't need to speculate, only conclude.

Scott Justusson

I have two pieces of 3/4" foam weather strip in the bottom of the shroud and haven't touched them yet. I also watched it from underneath with the hood closed, but only at 2500 rpm, didn't have a helper.

 

[landtank]

Hey Kevin, could you maybe give us an idea of the impact the 10K oil has on your MPG numbers. Just something close wold be a good start.

 

[Tools R Us]

Hey Kevin, could you maybe give us an idea of the impact the 10K oil has on your MPG numbers. Just something close wold be a good start.

I am not your man, don't care and flog my junk, don't drive with mpg in mind, it's bad so I don't aggravate myself by checking it! I could check it now, the only recent data that I have is running Hells and Spike in Moab, so if you want to sponsor my trip I would be happy to rerun those trails and provide data!

 

[landtank]

I was thinking that you would notice a difference if it was considerably more. Just a seat of the pants kind of estimate. Not something that you would compare to other trucks as a bench mark, but maybe seems the same or it guzzles the fuel like a 3 dollar hooker.

 

[Tools R Us]

I was thinking that you would notice a difference if it was considerably more. Just a seat of the pants kind of estimate. Not something that you would compare to other trucks as a bench mark, but maybe seems the same or it guzzles the fuel like a 3 dollar hooker.

I will watch the mileage over the next few tanks, to see if there's trend, I usually get about 230-240 miles to the light coming on. My main concern is a strong, solid, simple cooling system and if I have to give up a small amount of gas mileage for the added cooling capacity, I am good with that.

 

[SUMOTOY]

I have two pieces of 3/4" foam weather strip in the bottom of the shroud and haven't touched them yet. I also watched it from underneath with the hood closed, but only at 2500 rpm, didn't have a helper.

Fan flex from behind the shroud is not accurate at all. those tips move forward, and can only be measured by interference. I highly recommend using something other than the radiator core for this.

You need to have something right at the tip circumference against the radiator. My measures show under lockup 10k fluid, it sure flexes more than 3/8 in.

SJ

 

[Tools R Us]

Fan flex from behind the shroud is not accurate at all. those tips move forward, and can only be measured by interference. I highly recommend using something other than the radiator core for this.

You need to have something right at the tip circumference against the radiator. My measures show under lockup 10k fluid, it sure flexes more than 3/8 in.

SJ

Not to worry, the foam strips are inside the shroud, in the dipped part at the bottom, at the first place that the fan would touch. The fan would hit the shroud before it hit the radiator.

 

[SUMOTOY]

Not to worry, the foam strips are inside the shroud, in the dipped part at the bottom, at the first place that the fan would touch. The fan would hit the shroud before it hit the radiator.

Kevin:
on 8-10-05 Dan started a fan thread that included you. And in fact,many authored by you. It included Christo. I suggest you reread it carefully. Mine hit the shroud first too, that just didn't stop it from going further.

It would appear a LOT of folks have had fans prop into radiators, including toyota themselves. Christo solved his issue by putting a metal ring against the radiator core. I like that one!

A very good thread, and Photoman has some good ideas, so did Gumby.

https://forum.ih8mud.com/showthread.php?t=55521&highlight=christo+ringed+fan

Scott Justusson

 

[Tools R Us]

Kevin:
on 8-10-05 Dan started a fan thread that included you. And in fact,many authored by you. It included Christo. I suggest you reread it carefully. Mine hit the shroud first too, that just didn't stop it from going further.

It would appear a LOT of folks have had fans prop into radiators, including toyota themselves. Christo solved his issue by putting a metal ring against the radiator core. I like that one!

A very good thread, and Photoman has some good ideas, so did Gumby.

Scott Justusson

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.