aluminum fan hole to water pump shaft worn

[freak]

I put a new aluminum fan from Snyder's on last summer. This spring I hear a noise and upon investigation I find that the fan is loose on the water pump shaft. It doesn't look like tightening it will fix it. It was tight once and has the cotter pin installed. It appears that the hole in the fan has enlarged probably from the load the belt places on it. I don't think the belt tension was too high but just did it by feel. Anyone else ever have trouble like this?

[29spcoupe]

I had the same problem with mine. According to Snyder's, some of the older water pump shafts had the wrong taper. I ordered a new leakless water pump and new aluminum fan and the problem disappeared. John

[Tom Wesenberg]

Be sure to use a thin steel flat washer under the fan nut. Also, just like aluminum wheels on cars, it would be a good idea to recheck the tightness after running 50 miles.

[freak]

Originally Posted by 29spcoupe

I had the same problem with mine. According to Snyder's, some of the older water pump shafts had the wrong taper. I ordered a new leakless water pump and new aluminum fan and the problem disappeared. John

How long/many miles has it been working?

[freak]

Originally Posted by 29spcoupe

I had the same problem with mine. According to Snyder's, some of the older water pump shafts had the wrong taper. I ordered a new leakless water pump and new aluminum fan and the problem disappeared. John

BTW - did you buy the regular or no-grease model?

[29spcoupe]

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Originally Posted by freak

How long/many miles has it been working?

About 200 miles

[29spcoupe]

Originally Posted by freak

BTW - did you buy the regular or no-grease model?

I bought the leak less one that needs grease

[Walt Dupont--Me.]

I had 2 of those aluminum 2 bladed fans, they both wore out the tapper in no time, I finally bought a steel hub 5 or 6 bladed fan from Snyder's, didn't think I'd like it at first but got used to it, it really sucks some air, I recommend it. Walt

[Jacksonlll]

Very common problem and a little flaw in Henry's design. The tapers must match and be almost perfect. The nut just holds things together. Tightening it will not fix anything if the tapers don't match. The belt load is about one inch rearward of the rear end of the taper, so it is a cantilever load on that taper. If things don't fit, the slight wobble will pound things out with every rotation, and get very lose.

[bosstime2]

I'm having the same problem as well. I put a Synder's 2 blade fan on a new leakless pump two weeks ago and I'm getting some noise from it. I'm gonna take the pump and fan off this weekend and make sure things are sitting right.

[freak]

I think the whole problem (with mine) is what Tom Wesenberg described. I had no steel washer and the nut "cut" into the aluminum making the fan loose. I think a washer would have prevented my whole problem. I bought a new pump (which I don't think I need) and a new fan. It will definitely have a washer on it this time.

[Synchro909]

On our recent 9,000 mi,e trip around Australia, I had this problem with one of those plastic multi bladed fans. A helpful workshop owner allowed me to use his lathe. I put some epoxy putty on the taper and used the lathe to make sure it all ran straight and left it there over night. I've done about 10,000 miles since with no sign of trouble. I wondered whether it might have been caused by mismatched tapers and after this thread, I'm inclined to think that's what it was.
Thanks to the shop owner in Cunnamulla!

[Cool Hand Lurker]

Originally Posted by Synchro909

On our recent 9,000 mi,e trip around Australia, I had this problem with one of those plastic multi bladed fans. A helpful workshop owner allowed me to use his lathe. I put some epoxy putty on the taper and used the lathe to make sure it all ran straight and left it there over night. I've done about 10,000 miles since with no sign of trouble. I wondered whether it might have been caused by mismatched tapers and after this thread, I'm inclined to think that's what it was.
Thanks to the shop owner in Cunnamulla!

Synchro, I was just about to post a question about using epoxy like you did! You are a mind-reader!

I was wondering if I greased the shaft lightly so that the epoxy would not stick to it but would stick to the fan taper that it would work to fix the clearance issue and that it would last. I guess it would, eh?

The reason for greasing the shaft is so that I would still be able to remove the fan if necessary.

Thank you!

[Keith True]

I think the biggest problem with the fans loosening up is when installing them the key will ride up just a hair.It is hard to detect and doesn't take much to throw it all off.It will feel good,and you just might be able to tell when tightening the nut.Instead of the nut coming to a firm stop,it may feel like the last turn is pressing the hub on.That means the soft aluminum is trying to form itself up over the key.The hard steel nut against the soft aluminum without a washer is a real problem too.Another problem I've seen is people using never-seize on the shaft.Never-seize+steel+taper+aluminum=disaster.Taper fit needs to be dry,clean,no burrs,and dry again.Make sure there is no powdercoat,paint,or grease in the hub,same with the shaft.Then scribble all over the shaft with a magic marker.Slide the fan on without the key,hold the shaft by hand and press and turn the fan with your other hand.You will see just how good the taper joint really is.I've seen the locking collars we use on the shafts for end play be too thick,and the hub bottoms out on them and feels nice and tight.I've never seen a bad fan taper myself,but quite a few bad installations.

[freak]

While putting this back together... I observed that you really cannot use a washer unless you custom make one on a lathe. Even then the contact area would be no larger than the nut provides. Where the nut rides there is a slight recess. To do anything better you would have to chuck up the fan on a lathe and machine the nose so a larger washer could be used. I'm putting it back with just a nut. Being careful with the key as well. Best thing to do is keep and eye on it and retighten occasionally I guess. Keith True's tips are all good also.

[Bob C]

I used a 3/8" SAE flat washer and filed the hole to fit over the
shaft threads, it fit right into the recess. I would not use this fan
without the washer. I also used some valve grinding paste to
lap the fan hub to the shaft and then checked it with prussian blue.

Bob

[freak]

I measured a 3/8 washer OD at about 7/8". The recess is about 3/4" and it's not even a flat bottom. It tapers toward the edge. If I use a washer that fits the recess I really don't gain anything over the nut. Maybe our fans are different?

[Synchro909]

Originally Posted by Cool Hand Lurker

Synchro, I was just about to post a question about using epoxy like you did! You are a mind-reader!

I was wondering if I greased the shaft lightly so that the epoxy would not stick to it but would stick to the fan taper that it would work to fix the clearance issue and that it would last. I guess it would, eh?

The reason for greasing the shaft is so that I would still be able to remove the fan if necessary.

Thank you!

Hey Coolhand, I didn't use grease on the shaft. The epoxy is bonded to both the fan hub and the shaft taper. When the time comes to remove the fan, it will be because the shaft needs replacing. I won't be afraid to use a puller to remove the fan, even if it damages the end of the shaft - no loss.
Being a plastic fan, I won't use heat but as a last resort, I might.
At the time of the repair,I was just happy to be on my way again.

[larrys40]

I believe the problem is it wasn't tight enough at first or the taper is not matched. I use a small 3/8 impact to ensure that I get the nut on tight enough without putting stress on the blades or hub to tighten. It really does need to be tight and matched well. Put a little dykem blue on the end before you fit it on to make sure you have good contact. Do this without the key and rotate slightly when down to give you an idea of contact.
If all is good, remove, key, install fan and tighten.
I have done many and have not had one cause a problem yet. In the beginning when snyder was getting the fans done there was a problem but that was very early on. Since the reports are good. 10 years or more from now I guess we will know how they faired.
Larry Shepard