Clutch Fan

I've been debating going to a clutch fan in my 74. Anyone got any reasons why this is a great or really bad idea?

 

Why not electric if you're considering a change?

A Ford Contour fan is a perfect fit over the radiator, and it can be wired redundantly as there are two fans. It's worth a consideration...I'm sure a search here and on the web will turn up lots of info.

 

The factory fan and fan clutch will make your engine quieter at speed. Try taking the fan off and you'll see how much of the engine noise is fan noise (a lot).

That said, the only thing the factory fan clutch has over the electric fan is simplicity, IMO. The electric fan is less efficient (in turning fuel into cooling air) but gets back that loss of conversion power by running only when needed.

The factory fan, fan clutch and shroud works well though. Certainly quieter than a fixed fan.

 

Clutch fans are great for water crossings. Ease into the water. When the fan hits the water it will stop and not take out the radiator.....AMHIK. If running electric it also can be turned off.

 

In adding a fan clutch to a 1974 model with the 258 six that didn't have a factory fan clutch, how far with the addition of a fan clutch move the fan towards the radiator?

 

It gets kinda close probably a little more than 1/2 inch I put one on my 72 a few years ago when I did the power steering conversion. I could give an exact measurement when I get home this evening.

 

I'd be interested in the clearances as well. Sounds like something I'd be interested in doing for my '73 258 c.i.

 

Cutting it pretty tight. I'm not so concerned with an exact measurement other than just curiosity to this point.

I'd like to know if you've had any problems with the reduced clearance though.

jzeber, are you telling me the clutch stops the fan due to the internal temp drop due to the water being splashed up on the clutch or are is the fan clutch designed to give way to the resistance of the water on the blades? Sounds like it would still be a gamble if you didn't do as you said and "ease" into the water.

 

I just measured mine and it is just a little over 1/2 inch between the fan clutch and the radiator on my 72 with a 258. You have to use a very short fan clutch I used a Hayden part# 2765 from my F.L.A.P.S. I should mention that I am using a later model water pump because I moved my alternator to the passenger side so that I could mount my P/S pump but it think it is the same height that my 72-75 water pump was. You can buy the fan blade from 4wheel drive hardware or quadratec. A fan clutch is a fluid coupling that is filled with a thick oil so it never is completely locked, the bimetallic spring that is located on the front rotates a small shaft as it expands which is connected to a disk inside the clutch that has holes in it that allow or restrict the flow of oil inside the clutch, however if your fan blades encounter deep water with your engine at 6000 rpm it would probably still do some damage even with a fan clutch.

 

Ok good info here.. So I guess the next question is where to get the clutch.

 

It gives way to resistance not temp.

 

Picked up a whole assembly at the junk yard for $15. It is too long so I am going to look into the shorter one mentioned.

 

Just about any parts house should be able to get it for you, just give them the Hayden part# 2765. I don't know what vehicle that clutch is supposed to fit I just looked through Oreileys catalog at the dimensions for the fan clutches until I found one that would fit. 72 CJs didn't come with a fan clutch and the one that the parts house came up with for a 75 would not work. The one that I used came with a bushing that I had to slip over the water pump pilot.

 

'72 CJ-5 V8s have a fan clutch - only the 6s do not. Just for anyone that's thinking about the fan clutch for their V8 CJ.

 

Just wondering, are there 2 different snout lengths on the 258 water pump, ( the shaft for the fan)? I seem to have a deeper pulley than some I've seen and would like to get a shorter pump shaft, if possible, to swap on a clutch or electric fan. Right now I only have 2 inches from the fan mounting surface on the pulley to the radiator. This would be for a 1973 vintage engine.
Thanks

 

The fan clutch on mine measures approx. 2 1/2 inches from the flange that contacts the water pump pulley to the front of the clutch. The distance from the water pump pulley to the radiator is 3 1/4 inches. I have a stock radiator.

 

I am thinking about putting one in my F134 for my 62 cj5. I am in Miami, so, very hot! Any suggestions or alternative idea? Thanks!

 

I can't think of any good reason/purpose to install a fan clutch on an F4 engine.

 

Late to the party but my 75 came with a fan clutch.. I assume the 74 is the same setup and the fan clutch will have plenty of clearance. I have the stock 304