not enough clearance for fan

[asgi99]

Here's the resolution so you don't have to read through the whole thread.

Problem - fan rubbing against fan housing after replacing alternator

Resolution - tighten retaining nut properly. I tightened in place and it meant that the fan shroud nuts were no longer tight allowing the fan to torque and therefore rub against the housing. Make sure you tighten all nuts adequaty.

key words - fan shroud rubbing nuts clearance alternator
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I am in the process of replacing the alternator on my '83 sc. After installing the fan back into the fan housing and tightening the metal strip I noticed that the fan was not spinning freely - it was catching on one side. I loosened the metal strap until it span freely which I had hoped was the end of the problem.

Unfortunately, when I hooked up the fan belt and tightened the fan nut the problem reappeared. I am guessing that the fan is not true and is moving slighty in the housing causing the blades on one side to brush against the fan housing.

Any suggestions? Did I not tighten the fan shroud nuts adequately? There is a nut that holds the alternator into the fan - could this need extra tightening?

Maybe this problem would resolve itself if I turned the engine but I am concerned that I will destroy the fan blades.

Any help is much appreciated.


Ash

[masraum]

How easily did the alternater go back into the shroud? Was it a tight fit or did it slip easily right back in?

If it was a tight fit I'd say that was the problem, the nuts may not have gotten tightened enough and pulled the alt completely flush in the housing. Other people have reported that experience here before.

I assume it didn't rub, and there was no evidence of it rubbing before.

[Sonic dB]

The problem is the magnesium Fan Housing. It flexes when you tighten it down, and the circle goes oval and therefore rubs on the fan in some spots.

I recently purchased a new aluminum fan housing... and it is so rugged that tightening it down does not warp it. PM me for the source on where to get these.

[Rot 911]

You may both be right. The fan rubbing could be one of three problems: a bearing going bad, incorrect mounting of the alternator, or cracks in the housing allowing the housing to become oval shaped when you tighten up the fan housing strap.

[clarelaw]

Mine rubbed when I installed it after a rebuild. I tightened the nuts on the back of the alternator in a cross pattern and the rubbing went away. No problem (with the alternator) since.

[asgi99]

Thanks everyone. First point of order will be to retighten the nuts on the back of the alternator. If that does not solve the problem I will try putting in the old alternator to see if it is a problem with the new. If I still get rubbing it looks like will need a new aluminum fan housing.


Ash

[asgi99]

Fixed the problem. Nuts not tightened properly. Fan spins fine, alternator works great. Thanks clarelaw, Kurt V, Sonic dB and masraum. Your help is much appreciated.

I will post the resolution at the top of the thread. My first contribution! No longer a free rider!

[Sonic dB]

Good to hear it...problems solved. If your fan housing was warped or cracked...then its time to get a new one...