fan belt touches fan housing

[drtyler]

I just replaced the alternator in my 1975 911S, and put everything back together. Now, I notice the fan belt is touching the lower section of the fan housing. Pulled housing out, and reinstalled - same thing. Is there a trick to making sure the fan housing is forward all the way, or am I missing something really easy here?

I appreciate any responses. And yes, I feel like a complete dunce for this - one of the easiest jobs on this car and I can't seem to get it right.

Thanks,
Dane
'75 911S

[pa911]

Are you sure the alternator is the same length as the old one?

[drtyler]

Well I compared the two, and they seemed to be same. Old one was the SEV Marchal, and new one was the Valeo replacement with internal voltage regulator. Plenty of others that I have seen from searching the forum have done this conversion (I hesitate to call it an upgrade), and I haven't seen anything about this.

Fan housing reinstallation - after tightening the nuts for the plastic air nozzle/diverter, you slide the housing in as far as you can, then tighten the strap. Correct?

[Don LaVance]

I had the same problem when I did my Alternator on my 1988 911.
Problem was that there seems to be a small lip that the fan unit needs to be raised above on the bottom when slid back into place in order for it to move back into the original position needed to give you the needed belt to fan clearence. It is only about a quarter inch of extra movement but you will feel it when it slides in.
Problem is you have to remove the screws holding the shroud and loosen the hold down strap one more time in order to lift the fan and slide it up and back in the lower front. (next to the fan belt). All the belts needs to come back off also.

[drtyler]

Thanks for tips. I'll give that a try tomorrow. It sounds like that might be it!

[redstrosekNic]

This has been a bit of a PITA for me too. I found it helpful to have the GF tighten the fan strap while I hold the fan housing in it's proper position.

[redstrosekNic]

Make sure not to tighten the fan strap too much. The spec is 72in/lbs.

[Driver_X]

Check the stud length on both alternators.

[kodioneill]

Compare your alternators side by side. Some fan housings are cut deeper for alternators that are longer.

[Driver_X]

I ran into a similar problem on my '74. Turned out that it was easier to just have my alt rebuilt.

Alternator Question

[Gogar]

I think you should check again, I seem to recall that the SEV Marchal and the Valeo are NOT the same depth. They do look very similar, I'll give you that.

[JJ 911SC]

Originally Posted by kodioneill

compare your alternators side by side. Some fan housings are cut deeper for alternators that are longer.

+1

[pete3799]

Originally Posted by Gogar

I think you should check again, I seem to recall that the SEV Marchal and the Valeo are NOT the same depth. They do look very similar, I'll give you that.

My swap fit fine. Just needed the different clamping cap washer to fit the Valeo.

[maui44]

Make sure you placed the "top Hat" washer behind the fan.

[Mike Masterson]

Did you check the fan housing for cracked webs? I found three cracked webs on my fan housing while replacing my alternator recently. The car is a 1985 Carrera. The fan housing is made out of magnesium and doesn't "age" very well. I had adjusted my fan belt, but noticed a slight mis-alignment between the 2 pullies. The belt was also squeeking slightly. On removal, I found the cracks on the back side of the housing. As there is no repair for this, replacement of the housing is the only solution. Good Luck.

[drtyler]

So, I originally did not have the fan housing all the way in. Installed it, and belt no longer touches housing. However, after the post regarding the top hat washer, I know I don't remember dealing with one. It sounds like I need to disassemble everything and locate the correct washer, although the parts book does not seem to show one as a separate part number.

[drtyler]

Ok, everything is fixed and solved. Thanks all for the suggestions.

First time, I did not have the fan housing all the way back. Got it in there correctly, and everything lines up well.

However, I didn't remember replacing the top hat washer between the fan and alternator. So I double checked my old alt, and there it is. Rats. But, looking at the belt and installation in the car with new alt, everything is lined up perfectly. But, I take it all back apart to check. The new alt did indeed come with a new top hat washer already in place. So, everything back together again, and works great.

Thanks,
Dane

[maui44]

Outstanding

[redstrosekNic]

Glad everything worked out