help, fan contacting fan housing

[andy s]

Hey all, New to me 77 chassis, 3.0ltr, fresh rebuild and everything looks ok, but the alt belt was very loose (1 1/2" of play) and squealing.

I pulled the belt (725MM ) and put on a 710mm. I also noticed that the car only had 4 shims and I put on 2 more.

Put it back together and now the fan (11 blade) is slightly contacting the lower fan housing, just enough to make noise and scrape away about 3" of the powder coating.

I've pulled the Alt and checked that the 10mm nuts are tight and I checked to make sure there are 6 shims on the upper pulley (there were only 4, but I added 2).

So, everything is tight, right shims, I think the right belt (don't know much about 3 ltr motors), housing is in the grove, big strap is tight etc.....

Any ideas?

Thanks

[jjeffries]

I have an 82 SC with 190k miles. It developed a similar noise; was less than 3" of contact but ultimately I determined my fan housing had deformed over the years. The fact your contact happens at the bottom of the housing may suggest the same is happening with yours (as opposed to if it were on the left or right). I replaced my housing with a good used part and solved the problem. Best of luck to you, John/CT

[john walker's workshop]

The fan housings crack and belt tension pulls the fan down, so try adding a shim between the pulley halves to loosen the belt a tad.

Also--overtightening the strap can deform the housing enough to cause it to go oval. Try loosening the strap up a bit.

[juanbenae]

a number of people have reported a rubbing fan after having powder coating them due to the thickness of the material.

[andy s]

Yea, Juan, but it was not rubbing when I first got it, only after I put a better belt on... Now I have to figure out how to balance between tight and noisy or looser and quiet....

[mepstein]

That’s not normal. I would figure out what is really wrong. Maybe the bearings in the alternator are going bad.

[andy s]

Epstein, I checked the alt (like checking for a loose wheel bearing) and it did not seem to be loose at all...

[Joe Bob]

Bearing issue would produce a wobble and rubbing 360 degrees. Either the band is too tight, the belt or shims are an issue IF the fan housing isn't already deformed.

[Oneredspyder]

Before you put the belt on, spin the fan. Does it hit? Also try to wiggle it with no belt on, there should be no play. My housing had multiple hairline cracks that I dd not appreciate. Found a new magnesium housing in Germany.
86 Carrara.

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