Finally got my cooling system back together and the new fan tips just hit the bottom rolled lip of the radiator!! When I put the old fan on the table with the new one I can see why someone bent the blades on the old one-just not very well. There's not much room between the fan pulley and the radiator for the fan. (350 Chevy) I've already gone down to a 15" diamter fan, so it seems my options are to either grind each tip at the back end of the blade where it curls and hits the radiator or carefully bend each blade back a bit at the hub so the unchanged blade clears. My inclination is grinding-since I think I can do that more accurately than bending and unequal bends might imbalance the fan blade and wear out the water pump. Obviously I'd be changing the air flow the fan generates,but I don't know how much or how critical this would be. I'd probably need to remove about 1/4 to 3/8" deep by 3/4" long of the tip just to be sure it won't hit when the motor flexes. Any constructive comments on which option to do and how to do it would be welcomed. I do not want to exchange the fan or go to an electric fan. Just nbeed to know how to modify what I've got. Thanks.
I would cut the ends off myself...just be very careful that you mark each blade identically for the cut ...I doubt they are perfectly balanced from the factory.
Are you using a spacer between the water pump and the fan that is putting the fan so close to the radiator? I actually had the opposite problem with my fan hitting the alt. and crank pullies when I changed up fans. It was a balancing act to get the right fan and spacer combination so that it would clear the pullies, but not hit the radiator.
Curiously enough,the original blade used 4 washers to space it out a quarter of an inch from the hub. The new blade sits right on the pully which sits right on the hub, so there is no room to shift it back.
Hey, I'd start lookin for a 14" fan . I have repaired, and seen several hood panels that were damaged from flying fan blades; good thing the hood was closed. And you're correct about the water pump and weird vib- rations at high rpm from unbalanced fan blades, S****ey Devils C.C.
Thanks for the input. I just bought this 15" fan-moved down from the ancient 17" that was on there. I am reasonable certain I can remove the tips and get it pretty well balanced using a lawnmower blade balancer-if that is better than bending it.
DO NOT BEND!!! Now that you have that message. Most blades (plastic) are trimmed down) just like you are suggesting. You can do metal too. Just be very careful, remove all burrs and do no create any bends or stress risers and all should be good. Balance as you go and use good judgement (there now I sound like your mom or shop teacher). If you need more let me know. I unfortunatly know this business all too well!
Thanks. I'd pretty much decided to go the "cut the tip" route. My blades are metal and I think I can cut them quickly and cooly with a cut-off saw,then grind them smooth-probably even with a Dremel to keep the heat down. I really won't have to take a lot off-they don't hit by much. My lawnmower blade balancer fits the fan center hole,so I can get the balance pretty close-at least as close as it is now out of the box. I appreciate the advice.
mr 5 window.. we havent had the oppertunity to meet.. but I hope to sometime during my many travels through your area to williamsport. I hope that when I do get a chance to say hello your car isnt apart because the fan you trimmed or bent or whatever flys apart, or sends a fragment through the radiator.. or because you loose a waterpump to an imbalanced fan.. I would just buy a smaller fan.. how much could it be?? and how much is it worth if it saves you time and money down the road damn I sound like my father..
I appreciate the concern. I am considering removing approximately 0.3 square inches of material off the trailing end of the fan blades. I can grind the fan into at least as good a balance as it is now and far better than the old fan I took off. I won't be anywhere near the blade attachments or hub,so I don't see things flying apart. Mostly, I was concerned about losing air flow off the blades because I'd be removing part of the curl. I haven't seen any 14" fan blades out there for the 350,though I am sure they exist. If my cutting goes awry,guess I'll be looking for one quickly.
Update. Had my buddy, and engineer,look at it. I ended up removing just a triangle 1/2" high by 7/8" at the base from the back of each blade tip. Painted up and drying,we'll see how it flies.
Why not use a raised water pump ?? Then you can use a 17" or a 18" fan. Like one of these ... shown on Boone's Model A ... ( photo by Boones ) ...
Chevy made a short and a long waterpump. If you're using the long pump switching to the short one might solve all your problems. I'd ***ume you're already running the short one, but I thought it was worth mentioning...
Well,I'm just ignorant,I think Ihave the short pump, but I'm not sure. What's the critical measurement? As for the whole thing,the raised pump is okay-but I am looking for a more traditional look, a cheaper fix and one that doesn't involve taking the front off the car. But I may have to consider that if my t******* doesn't work. Actually the fan looks pretty good.What I trimmed off the back of the blade matches the angle on the front of the blade.
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