Fan Uses Radiator As Snack!

[CDOG]

I knew when I put this cooling system together that my clearances were marginal at best. After 2500 miles and a few good trail runs I thought I was in the clear. Well, this weekend I was out testing out my new BFG 35" MT's and actually found some mud here in Tucson. I got on my mildly built 302 to get through the mud and heard a sound no man should have to hear. I am guessing that the tires transfered the torque back through to the motor and it went forwrd and hit the radiator. Possibly the front clip bowed a little bit also. I have a Summitt universal fit aluminum radiator that was reccommended by one of the guys on here. I love the radiator and it was only $169. Even without a fan shroud I have never had any cooling problems here in AZ. The stock mounts were gone so I purchased some and welded them in but they only gave me about 3/4" of clearance at the top of the radiator. It leans inward for some reason. I also got a 1" fan spacer that gives me 1/2" of room from the fan to the belts. My motor is a 302 from an 89 Mustang that I believe was serpintine but was converted to two belts.

My plan for now is to mount the top brackets on the outside of the clip and get a little more room and modify the lower bracket to get it closer to the front also. I looked at electric fans, but I really think I will have clearance problems because some of them are up to 4 1/2" deep. Then I will need room from the motor to the back of the fan.

Questions:

How much room do I need between the fan and radiator?

How does everyone else have room and I don't with a 302?

Should I get an electric fan that is only about 2-3 inches deep.

Any suggestions or advice would be appreciated, and yes i am in the process of searching past posts.

Thanks

Chad

 

[Tito]

Looks like it survived?

 

[66ALRIDE]

That is why I run an electric fan. My buddy just placed a new aluminum radiator in his and had it in about a week when he hit a water hole and sucked the fan into the radiator. No radiator shop in town would touch it, so we bought some 2 part epoxy and glued it back up. So far it has worked, but will be replaced before summer. And yes that is an awful sound.

 

[CDOG]

I should have added that. It got in too far at the bottom which is further away oddly enough and it has i good size hole in it.

 

[77BroncoWag]

need one of those fan guards
cheap insurance

 

[CDOG]

With the current setup, a fan guard would not help. Things are just too close, it would be hitting the guard all the time. What I need is room.

 

[CDOG]

Also, how much room do I need between the end of the fan blades and the fan shroud. I have a 15" fan.

 

[broncnaz]

Might want to try a fixed pitched fan like BC sells. You can ditch that long spacer and gain some clearance at the radiator. You may have to run a shroud with it as they dont draw as much air but at least you'll have some clearance.Might want to hurry before the mud holes dry up around here.
Usually you'll want about 1" of clearance around the blades and the shroud.

 

[DonsBolt]

I think part of your problem might be old and worn motor mounts.I have a set of the extreem heavy duty motor mounts, that keep the engine from moving foward.

I would also look into getting a set of these.

 

[744x4]

I use a shroud and a Derale Fixed pitch fan R/R and it moves lots of air but I have a serp setup and a stock thin spacer ( with the holes slotted) and a rad guard and it is a tight fit but I have had it on its side and still no hitting.Drop back on the spacer and fix the top tilt and add the guard.

 

[CDOG]

I definitely plan on getting a shroud if I stay with a mechanical fan. I will check into BC's fan. The spacer keeps the fan out of the belts by 1/2" in the current setup. How much clearance do I need to the radiator to be safe. New motor mounts, I just have very little clearance. It was my fault.

 

[CDOG]

I haven't found a 3/4 inch spacer yet, that would give me 1/4" clearance from the blades. I will check the Derale fan. Thanks

 

[csjr]

Get rid of the crap flex fan. I put a flex fan through a rad guard and two cores of a 4-core rad due to too much speed and too deep water. Now, I don't drive silly like that, but I run an 18" fixed fan. It is solid and will pull the truck through the water like a propeller without flexing and eating the rad. The flex fan used to rub on the guard regularly. Secondly, check your body mounts at the front. When I bought my rig it had all kinds of those horrible sounds up front and while fixing stuff up I found the PO had neglected to put a bolt through the body mount that is under the battery tray. This allowed the core support to flex all over the place, but mostly into the fan. Maybe your body mount has come loose as well. Water is fun eh? Wait until you get a funny smell rolling down the highway and realize your bearings are welding themselves together because you just washed all the grease out of them while running for miles through knee to waist deep water....oops, I digress.

 

[joe]

mine clearance is about the same, maybe even tighter, i run a fan gaurd for insurance but the thing that does it all is monster motor mounts i got from west coast broncos. there solid and will not let the engine move much. i wheel it hard and have not had an issue yet. i do run a new derale fixed pitch fan but it wont flex. pulls around 4200cmf. my gaurd has touched just enough to scrape the paint on it but i never heard it.

 

[DonsBolt]

You could allways install some chain or cables to keep the engine from jumping foward, if you don't want, or can't replace the motor mounts.

I welded on some brackets to the side of my radiator, and mounted it to the radiator support

http://classicbroncos.com/forums/sho...t=81783&page=2

 

[CDOG]

For the guys running fixed pitch fans, they do make them for non serpantine systems correct. I am still searching for them.

 

[DonsBolt]

For the guys running fixed pitch fans, they do make them for non serpantine systems correct. I am still searching for them.

ya stock bronco fans

 

[CDOG]

If I am going to run a mechanical fan and shroud, I need to know how much of the fan needs to be inside the shroud. All, half, etc.

 

[744x4]

Half in half out

 

[72Sport]

I definitely plan on getting a shroud if I stay with a mechanical fan. I will check into BC's fan. The spacer keeps the fan out of the belts by 1/2" in the current setup. How much clearance do I need to the radiator to be safe. New motor mounts, I just have very little clearance. It was my fault.

Take your spacer to a machine shop and have them cut it to the length you want. Your flex fan flattens out as the rpm increases which means it moves farther away from the belts as rpm increases. The front of the fan blades are rigid and move very little if at all.

I have a serpentine system on mine. I had my spacer shortened so I have about .300 of an inch between the back edge of the fan and tensioner pulley bolt. I ended up with about 1 1/4" between the fan and radiator. If you get a radiator guard make sure you center it on the center of the fan not the center of the radiator. The guard is about 3/16" thick.

If your motor mounts are worn they will let the engine move when under load. Your big tires may have caused the mounts to come apart.