16 touring restoration..newbie here.
My fan belt keeps slipping off. There is no water pump. I have the belt going just between the pulley on the crankshaft and the fan.
Is there supposed to be something else that holds the fan on? I'm pretty sure I had it tightened down well.
Sounds like your fan shaft isn't parallel with the crank pulley. Check it with a square. If it's off, remove the fan, mount in a vise, and bend the arm with a stout pipe wrench. Re-install and re-check. You might have to do it two or three times until it lines up. Don't use heat to bend it unless you have no choice.
It sounds like you might have warn bushing in your fan hub allowing it to not be running true with the crank pulley.
The fan belt needs to be centered. Do not over tighten it. Be sure you have the proper pulley and that they are in line. The pulley should have a crowned center and when in proper alignment the belt will stay centered.
OK so I'm a slow one fingered typist.
It might be the belt was not made correct either?Bud.
So, there is not another part that is like a belt guide?
Some of us use this accessory belt guide. Not as good as fixing the alignment but they work. Some of the parts dealers sell them or they can be made fairly easily.
Yes, stock there is nothing else to keep the belt on. As for tightness, newbies tend to run them too tight. You should be able to turn the fan with a little resistance when the belt is tightened
To be technically accurate, Ford stated that a pull on the end of a fan blade of 5 lbs should allow the belt to just start to slip on the pulley. Forget the guides and fix it right by getting the 2 pulleys exactly parallel with regard to their shaft placement and then centered over each other. If the pulleys have little play on their shafts then a straight edge across the front of the pulley will tell you if they are parallel. It then takes very slight crown on one of the pulleys to keep the belt on but most of the time there is a slight crown on both of them. That is all that Ford used and it works perfectly.
If properly adjusted you can move the center of the fan belt an inch with slight pressure from your pinky finger. It needs to be just tight enough so the belt turns the fan.
So...John...when you say, "fix it right by getting the 2 pulleys exactly parallel" is there some adjustment to get them that way, or do I need to bend the fan arm?
hmmmm.. I put it on and it comes right off...
Assuming your bushings are not worn out and the pulleys are running true (Not wobbling), if the fan shaft is not parallel to the crankshaft, you will have to bend the arm to get it that way. Or maybe find a better arm. The aluminum clamp on type crank pulleys have a flange that will help the belt stay on. 'Course, then there are those who hang the fan on the wall and mock the ones who don't do the same, so the solutions really run the gamut.
Are there other photos that might help with the diagnosis?
For what it's worth from one semi-newbie to another ...
My Dad always had a belt problem when he had this car. Once I got the (gasp!!!) water pump working properly, and got everything aligned, I haven't had a belt slippage/slide-off issue since. (To make the anti-water pump folks happy ... I DO plan on taking it back off this coming spring .. maybe yet this fall, if I get time) .. as I think I finally have the proper no-pump belt!)
I ran it without a fan for the tail end of last year's season, without issue... and without overheating.
Michael ... it doesn't look like there is a nut on the end of your fan driveshaft ... it would be on the end sticking out toward the motor. It's a castle nut, so you can put a cotter pin/key (I never know what to call those things)through it, and bend over to lock.
Also looks like your fan pulley already has the shoulders on it, and that belt probably can't go anywhere at 'that' end. Without a little slop to move back and forth .. if it's not straight above the crank pulley .. it would force the belt off the crank pulley.
If you pull the fan pulley and arm off, and take the drive shaft off the arm .. is there a lot of slop in the bushing? If so, that would allow the pulley (and fan) to 'droop', making your alignment problem worse.
No photo, but the last entry here may help you:..
....have you done the "straightedge check" as advised above?
After checking alignment, the belt should not be real tight. If you have a small fish scale, measure the fan slip by hooking a fan blade near the outer end with the scale and pull. It should take no more than 5 pounds before the fan belt slips on the fan pulley.
If you have a car that the belt NEVER slips off from and you give the fan blades more pitch it can cause the belt to throw several times in an hour's running.
Compare your fan blade pitch with another fan to see if someone has tried to make the fan move more air.
The only problem with the plumb bob thing is if the engine is not sitting exactly level. First check to see if either pulley wobbles loosely at its hub. Fix that. There is almost no chance that the crankshaft is bent and part of the problem so you end up having to bend the upper fan arm to get things aligned. If you measure the distance from the bottom edge of the bottom pulley to the top edge of the top pulley then get something that has a straight edge at least that long. Put that straight edge across the edges of whichever pulley is most forward. View the gap between that straight edge and the 2 edges of the other pulley. If the gap is equal then the shafts are parallel but you may need to move one of the pulleys or both to get them to be above each other at their belt centers. Typically the belt falls off the front edge because the top pulley is leaning forward with its top front edge further forward than its bottom front edge. Forget the crank pulleys with extra ledges on their edges since they will just tear up the belt edge if the pulleys are not aligned and once aligned the edge flanges do nothing. The pulley simply needs a bit of crown to it in its center and it isn't critical. Don't add crown until you have the pulleys parallel and hubs snugged up since most likely you won't need to add any crown.
The timer rod should be passing UNDER that metal radiator water tube and not over it. Someone may have bent the fan arm forward to get it out of the way of the timer rod which is in the wrong place and it may be in the wrong place because it was put there to clear that accessory oil line which clearly seems to interfere with the path of the timer rod or at least the picture angle makes it look that way. The root cause here may lie with incorrect location of that accessory oil line. Can't tell without a side view since camera angles can distort the way things look to be.
1909-1920 the nut on the fan shaft is a grease cup, not a castle nut. Part #3970.
As was stated already, the pulleys must have a good crown, that is what keeps the belt centered. I have brought the crown back by sliding the fan pulley on a longer bolt and gently running against a grind stone. If enough meat is left you should be able to re form the crown. Most times the crank pulley being steel won't wear much. KB
Steve .. ahh .. so it is! .. but it looks like there is a nut for the through-bolt for adjusting, then the grease cup goes on after?
What is the clearance between your fan blade and radiator? Looks much closer (I assume = better) than mine!
This Am, I changed fan arms, and still no luck...though it did take a little while longer for it to fall off.
John, I looked closely at the oil return line...it is not hitting the belt at all.
I'll wait till it cools down a bit, take it apart, and do the straight edge test as recommended.
ok...when I do the straight edge test, the crank pulley and fan pulley seem to be parallel. However, the fan arm pulley seems be setting back just a little bit. Like of I could advance it forward a bit, it may help. Is it ok and kosher to place a fender type washer over the bolt the holds the fan onto the engine block?
I have two '13s, with original fans and brackets. On both cars, I've had to put a washer between the fan bracket and the timing gear cover to get the belt to track right. They stay centered perfectly.
It could be that the belt is stretched. Sometimes if the belt was overtightened, it will stretch so that one side is longer than the other. It will then run off.
I have one car which the belt will stay on if I run it so loose that after the engine is stopped the fan keeps on spinning! If I tighten it any farther it will run off. This particular car is a 26, so the fan is mounted on the water outlet neck and cannot be moved closer to the engine.
Anyway, try different things and eventually, you will get it to work. You might even need to get a new belt.
It's been so long since i bought any i can't tell if they are available anymore? Fanbelt= GATES!! Bud.
well...I did all sort so of things. Finally resorted to keeping it pretty loose, and adding one of the little after market belt guides. I hate it, but i did it.
Then the darndest thing happened. I was running it up and down the road sitting on the gas tank (the body should be ready this weekend) and the thing just stopped running.
After scratching my head for a while, I figured out you have to put gas in them now and then.
Geezzz...newbies for ya.
I did that once with a 1971 Plymouth Barracuda convertible I used to own. I took it to a tire shop to have new tires put on it and they called back an hour or so later to tell me that my car was ready, but they couldn't get it started. Turned out I had driven the car to their shop on the last bit of fumes in the tank. Luckily, they were right next door to a gas station, so they helped me push the car next door to fill it up. Embarrasing!
Dennis, here's a closeup for you. Nope, no other nut.
My fan-to-radiator distance is 7/8". I don't know if it's supposed to be, but that's what it is.