Hello,

I have a small problem with the fan of our 1929 Model A Roadster. I use a 2 blade cast aluminium fan. In the past it got a bit loose and it was possible to move the fan on the shaft. As I removed the fan from the shaft, I have seen, that the woodruff key is a bit worn. But I reinstalled it again since I don't have a new one at the moment, put a washer between castle nut and fan, and the fan is now fixed on the shaft. But… it turns not evenly, not round. The pulley or hub moves a bit for and backward, I would say 1 millimeter ( this is .04 inch ). I don’t mean a movement of the shaft. I hope you understand what I mean. I don't know the special english word for this movement.

My question is now : Is this movement a problem and is it because the woodruff key is worn or the fan ? I think this movement could be bad for the water pump bearings.

Thanks for your help in advance.

Kind regards

Tom

Tom-
This is not good. The fan is not straight on the waterpump shaft, you have a "wobble". It will continue to wear the key, enlarge the slot that the key goes into and ruin the fan. Also not good for the water pump.

I think the problem is the bad key caused by fan not being tight on shaft before. Try a new key and perhaps also use the washer with the new key when you tighten the nut so that it is not the tiniest bit loose.

It's possible that while the fan was loose on the shaft- before you tightened it with the washer- that the movement caused some wear either on the water pump shaft or in the hole in the fan pulley. I don't think the woodruff key would cause the wobble you are seeing now after tightening it snuggly, as the shaft and pulley are tapered, and once tightened should have no relative movement. I don't think driving with a wobble in the fan is a good idea. I would try a new fan and a new woodruff key to see if that fixes it.

Jim, Pete. Thanks for your answers.

Now I know that the word which I was looking for was “wobble”. Thanks for this.

And thank you of course for your hints. It seems that the shaft is ok but with the hole in the fan I am not sure. I will first try it with a new key and than I will see what will happen. I guessed that, that it would be bad to drive with this wobble.

So I will try to get a key here first. They will mostly sold with the castle nut and they are very cheap so the dealers here says often : This order is to less to send the part. And from USA there is a lot of shipping costs.

Regards

Tom

There have been a rash of repro alumnium 2 blade fanes that
are of such poor quality ( not straight and severly out of balance also some with hole taper wrong ) that they will cause the problems that you have. Go to Farnbarn.com and post there to get info on their poor quality.