rad fan

jwalterus · May 22, 2016

anybody know the diameter of the stock fan? ordered a nylon flex fan for the mustang, figure I'll give one a try on the truck sans clutch (I'll make a spacer/adapter to fit) and see what happens, but it's dark out and I'm too lazy to go with a flashlight and tape measure LOL

oh, 87 short/wide rad

79jasper · May 22, 2016

I can't remember, but I don't think it'll move as much air as the stocker.

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jwalterus · May 23, 2016

79jasper said:
I can't remember, but I don't think it'll move as much air as the stocker.

Sent from my SAMSUNG-SM-G935A using Tapatalk

at higher r's, that's true, but generally below about 2000 a flex fan moves more air because of the extreme profile (about 80* on the blades), and it's about the same at the 3k(ish) mark

I figure I'll be the guinea pig on this one, best case, it helps cooling and frees up a little power, worst case, it's a $20 frisbee of death LOL

I've also thought about checking the threads on a hayden heavy duty fan clutch I have in the shed, it's for a big block, they are supposed to be much more efficient at spinning the fan (faster spinning) when locked

icanfixall · May 24, 2016

You recall a posting about how to modify your fan clutch thermal spring??? You remove the spring and straighten it out where it has the bend to fit the housing. Then rebend it so it ends up a bit longer that original. Now the fan locks up around 200 degrees.. Instead of around 240 degrees like many original fan clutches do. What the spring does is closes the internal vale bypass so none of the viscous flid can bypass and allow more free spin of the fan.

IDIoit · May 24, 2016

running a nylon fan IMO is a disaster waiting to happen.
on any vehicle thats not running an electric fan....
i have no data or scientific background on this matter, but the thought of it makes me cringe!

Hydro-idi · May 24, 2016

Agreed. I don't think it will move enough air to properly cool down these engines. There's a reason why these diesels have a 30 lb metal fan & clutch. Sure they use some hp and fuel to turn it, but that's not really the concern when owning one of these trucks lol.
IMO, the stock cooling system does an excellent job at keeping the engine cool. Upgrade to a aluminum rad & temps will be even more manageable when towing.
If you have a good fan clutch, rad, OEM thermo, & water pump, you will be good to go.

icanfixall · May 24, 2016

Our fan outside diameter is 21 3/4 inch. Kind of difficult to measure because no 2 blades are 180 degrees from each other. The center hole measures 4 15/16 inch. I did not measure the bolt pattern. I have no way of measuring the pitch but it sure cuts a big piece of air out of the flow path.

jwalterus · May 24, 2016

I know a lot of people are anti- plastic fans, but the only ones I've ever seen (or heard of) let go have been at high rpm, and generally, they have some damage already

my cooling system functions perfectly on my truck (along with the rest of the mechanical systems), I'm just kinda looking for some crap that could/should be looked into, people are always asking about performance mods on these engines (to which I quote my grandfather: "it's like putting soup in a sieve...." :rotflmao

), and with the low rpm of these engines, it might be a decent thing to do, and if I run into problems with it, I'm prepared to deal with the consequences ;Sweet

icanfixall · May 24, 2016

Well that sounds like a good plan. Many years back.. Maybe 10 or so I thought a power stroke fan was a great idea for our idi engines... Till I noticed it was turning counter clockwise when facing the engine. I was even designing a way to make is fit if it turned out to be too large for our shroud. I can do many things.. But changing the way a fan draws air is not one of them. Simple flipping it over and bolting it on the clutch will not work. Sad too...

FORDF250HDXLT · May 24, 2016

icanfixall said:
You recall a posting about how to modify your fan clutch thermal spring??? You remove the spring and straighten it out where it has the bend to fit the housing. Then rebend it so it ends up a bit longer that original. Now the fan locks up around 200 degrees.. Instead of around 240 degrees like many original fan clutches do. What the spring does is closes the internal vale bypass so none of the viscous flid can bypass and allow more free spin of the fan.

fuel economy and performance will both take too much of a hit if you do that Gary.needlessly to since 240F isn't harmful to the engine.
best bet; e-fans.

riotwarrior · May 24, 2016

@icanfixall....is it shorten the stock spring....or lengthen it Gary, to change the temp to sooner lockup?

I thought it was shorten...but :dunno

I dont recall.

CDX825 · May 25, 2016

Ive pondered the idea trying to find a nylon fan. Our stock fan is very heavy because of the center hub. All that weight has to eat power plus its wearing the water pump bearing.

I think a nylon fan with more blades than the stock fan would be a great improvement.

icanfixall · May 25, 2016

riotwarrior said:
@icanfixall....is it shorten the stock spring....or lengthen it Gary, to change the temp to sooner lockup?

I thought it was shorten...but

I dont recall.

WEll Al now I'm not so sure of what I posted. Russ will know for sure. I think he was the person that brought this to the forum. If some recall the MS Tech modified fan clutch is doing this exact thing. I have run their modified fan clutch for more than 15 years now. But they are damned expensive for what they are. They purchase a stock oem clutch and modify the spring. Look them up and see what they charge these days. They are located in Babylon New York.

riotwarrior · May 25, 2016

icanfixall said:
WEll Al now I'm not so sure of what I posted. Russ will know for sure. I think he was the person that brought this to the forum. If some recall the MS Tech modified fan clutch is doing this exact thing. I have run their modified fan clutch for more than 15 years now. But they are damned expensive for what they are. They purchase a stock oem clutch and modify the spring. Look them up and see what they charge these days. They are located in Babylon New York.

Ya I am not seeing how one could safely make spring longer and function but shorten yes....

@typ4 whats the scoop.

typ4 · May 25, 2016

I lifted the spring out of its outside tail mount and "advanced" it a little then reattached.

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