Fan Clutch Mods

[Redcbr007]

Anyone ever heard of welding the fan clutch so it spins/cools constantly? This would NOT be for a DD. I was told you can shoot a screw through it/weld it/etc.. Anyone have some first hand info or a link w/ some info on this topic?


thanks

-Red

[Eagle]

I know a guy down-state who welded his, and it is a daily driver. Why should it be a problem? Back when men were men, women were women, and cars were cars all fans were solid steel and there was no such thing as a fan "clutch" or a flex fan. The amount of horsepower it wastes is negligible, but it does make a lot more noise.

[RichP]

I know a guy down-state who welded his, and it is a daily driver. Why should it be a problem? Back when men were men, women were women, and cars were cars all fans were solid steel and there was no such thing as a fan "clutch" or a flex fan. The amount of horsepower it wastes is negligible, but it does make a lot more noise.

Amen to that, ever listen to one when the engine is COLD, hood open and you first fire it up, that clutch is engaged and that fan ROARS for about 20 seconds. Woud drive me nuts if it did that all the time.

[BrettM]

anyone got a picture of one welded, or showing where to weld? Seems pretty straight forward, but I'd like to see anyway. I need a new fan clutch and this sounds like a good alternative to spending $100+ on a stupid fan clutch. I'm not too concerned about noise either with a loud exhaust, big tires, little interior, no doors, etc.

[FELIX]

Instead of welding, they have constant drive kits. :dunno:

[Redcbr007]

Instead of welding, they have constant drive kits. :dunno:


you can weld one for free though :D

[techno1154]

I had a fan clutch go out on me in at the most inappropriate time. I drilled it and put a bolt and not through it. I used it for about 2 months before replacing it with dual electric fans. The only draw back is at 2,000 plus RPM on the highway you could hear the fan roaring above the road noise.

[RichP]

you can weld one for free though :D
Yea, but how does that effect the balance, save money on a fan clutch only to have to replace other parts from out of balance components would bite.

[techno1154]

Yea, but how does that effect the balance, save money on a fan clutch only to have to replace other parts from out of balance components would bite.

I agree. I was always a little worried about something else like a bearing going out because of that but up to now everything is still intact and working fine. Yea, with a bolt through one side the balance is bound to be upset.

[burntkat]

Amen to that, ever listen to one when the engine is COLD, hood open and you first fire it up, that clutch is engaged and that fan ROARS for about 20 seconds. Woud drive me nuts if it did that all the time.

ummm... you DO know that when the engine is cold the fan clutch is disengaged, right?

[techno1154]

ummm... you DO know that when the engine is cold the fan clutch is disengaged, right?

Wrong!! I have heard that talk many times. All vehicles I know including Ford and GM that have a similar fan clutch the fan spins as long as the engine is running even when it is below 0* outside. If anyone could prove otherwise, I would like to hear your experiances.

[RichP]

ummm... you DO know that when the engine is cold the fan clutch is disengaged, right?

Incorrect, the fan clutch uses a fluid and when it sits overnite or for several hours the fluid settles to the bottom. When you first fire it up it takes about 20 seconds for the fluid to redistribute and free the fan up. Until then it is locked just like it's hot and engaged. Thats why they roar so much on the first start. Our two TJ's do the same thing.

That is unless I have the 'roaring' backwards and it's only noisy when it is totally free wheeling but I don't think so.....

[Dr. Dyno]

I know a guy down-state who welded his, and it is a daily driver. Why should it be a problem? Back when men were men, women were women, and cars were cars all fans were solid steel and there was no such thing as a fan "clutch" or a flex fan. The amount of horsepower it wastes is negligible, but it does make a lot more noise.

I wouldn't say negligible. You definitely notice the engine revving up faster when you remove the clutch fan altogether and you definitely notice the extra drag when the clutch fan tightens up and starts roaring. That's why I converted to dual electric fans:

http://www.angelfire.com/my/fan/electric.html

[2xtreme]

You can tighten up the spring on a older fan clutch (pre 91) I have no idea if you can do this on the newer ones (never looked at one). I had one that I did not trust and so I tightened it up a few turns and I could tell a slight difference in speed.

I considered drilling the hole and putting a bolt through it, but in my mind tightening up the spring that is there is the ultimate solution, still provided less stress on components on start up but is tight during driving. This clutch is now my trail spare.

Not worth welding, just tighten up the sprng.

Michael

[BrettM]

You can tighten up the spring on a older fan clutch (pre 91) I have no idea if you can do this on the newer ones (never looked at one). I had one that I did not trust and so I tightened it up a few turns and I could tell a slight difference in speed.

I considered drilling the hole and putting a bolt through it, but in my mind tightening up the spring that is there is the ultimate solution, still provided less stress on components on start up but is tight during driving. This clutch is now my trail spare.

Not worth welding, just tighten up the sprng.

Michael
mine is an 88, so I guess this is an option for me. I've never had the clutch off before, so I don't know what spring you're talking about, and my truck is 2000 miles away for the next 2 months so I can't go look. Is the spring you're talking about fairly obvious when you take the clutch off?

[2xtreme]

mine is an 88, so I guess this is an option for me. I've never had the clutch off before, so I don't know what spring you're talking about, and my truck is 2000 miles away for the next 2 months so I can't go look. Is the spring you're talking about fairly obvious when you take the clutch off?

Extremely obvous. If I remember correctly the shop manual also discusses how to do this or check this spring. Might be worth looking at also.

Very easy to do.
Michael

[5-90]

Yep. On the "HD" fan clutches (like ours) there is a "snail" spring on the front face. I'm not sure what it's for, but if you have a spring on yours that's where you'll find it.

Meanwhile, I'm working on drawings for a fan "spacer" hup that will allow the outright elimination of the fan clutch and convert the fan into a purely string driven thing - it's not that I don't have faith in electrics, I just like to simplify critical parts and make things as bulletproof and Murphyproof as possible...

5-90

[BrettM]

Yep. On the "HD" fan clutches (like ours) there is a "snail" spring on the front face. I'm not sure what it's for, but if you have a spring on yours that's where you'll find it.

Meanwhile, I'm working on drawings for a fan "spacer" hup that will allow the outright elimination of the fan clutch and convert the fan into a purely string driven thing - it's not that I don't have faith in electrics, I just like to simplify critical parts and make things as bulletproof and Murphyproof as possible...

5-90
post pics of that when you make it! and/or drawings

[Redcbr007]

sounds like me and brettM are in the same boat {tryng to get rid of our fan clutch's :P and cool down the heep more}

[PaulJ]

It's not really a spring. It is a coiled bi-metal strip. When the clutch assembly gets hot, the coil winds (or unwinds) and turns a small shaft that protrudes through the front of the assembly. Turning that shaft changes the amount of clutch slippage. Hayden says the fan will turn about 50% of shaft speed when the clutch is engaged. A heavy duty clutch will give more lock-up; however, it doesn't appear they have one for XJs.

[Atl XJ]

I wouldn't say negligible. You definitely notice the engine revving up faster when you remove the clutch fan altogether and you definitely notice the extra drag when the clutch fan tightens up and starts roaring. That's why I converted to dual electric fans:

http://www.angelfire.com/my/fan/electric.html

I agree, I can definitely tell a difference when my fan clutch is engaged vs not engaged. It definitely puts a drag on the engine. I also agree that it would be annoying as hell especially on the highway. When my fan clutch when bad it would roar on the hwy and it was really loud and very annoying.

[BrettM]

let me be sure I understand this, the clutch fan (when locked) should be spinning less than the speed of the shaft/belt?? I don't think mine is working properly for a few reasons:

1) when everything is nice and hot and I turn the truck off, I can spin the fan 4 or 5 turns with one good push.

2) when I put my hand in front of the radiator by the mechanical fan I can't feel any air moving, I can in front of the electric.

how do I check for sure?

[Dr. Dyno]

What you've just said confirms that the viscous clutch on your mechanical fan is toast. Either replace the clutch or ditch the whole fan altogether in favour of an electric unit. You'll gain some HP and get better gas mileage.

[Redcbr007]

let me be sure I understand this, the clutch fan (when locked) should be spinning less than the speed of the shaft/belt?? I don't think mine is working properly for a few reasons:

1) when everything is nice and hot and I turn the truck off, I can spin the fan 4 or 5 turns with one good push.

2) when I put my hand in front of the radiator by the mechanical fan I can't feel any air moving, I can in front of the electric.

how do I check for sure?

I ot the same problem, it sounds like be have some bad fan clutches... Mine is a trailer queen anyways, so hwy speeds arnt an issue to me (she's never seen anything faster then 30 :P ), So I like the screw/bolt Idea..

-Red

[resonant_evil]

When my clutch went I replaced it with an electric (210 ?) it has been years, anyway, didn't pull enough air. Couldn't find the right size flex fan so went to a junk yard and pulled the clutch off a heap for 10 dollars. It's still good 2 years later.

I could definately tell the differance between fan and no fan. Not enough to put it on the priority mod list now that it works.

What electric fan are people running?

[balloo93]

I bought a Hayden clutch from O'rieley's for around $30 and it works great. I ran a Permacool 14" fan, but HATED that damn thing. No shroud so less pull. It did a little worse than stock, so i just replaced the clutch.

Too bad Flex-a-lite doesn't make a reverse rotation 12" flex fan, I would run one of those in a heart beat.