I think its time for a new fan!!

[D'STARGA]

So, I end up with friday off so I start to tackle my alternator replacement and get it all out wich wasn't too bad and what else do I find? A 1/4 chunk of a fan blade is gone. $h!# now I guess I will have to try to find one. Any ideas where to look for an fan for an 82 SC?

[EdT82SC]

That doesn't look too bad. I don't think it needs to be replaced.

[bit]

Hi!
Why bother (unless it is really buggin you)? it is on the back side and no one will really see it. Plus the broken piece is so small I don't think it would cause any significant balance problems or excessive wear on the alt. I have a piece like that off of my fan too, no problem, and it is not visually noticible.
Cheers,
.Steven
1980 911SC

[AvonGil]

Take a similar chunk out of the opposite blade if you are scared about balance.

[MichiganMat]

Unless you've got yourself a concourse car I wouldn't sweat that one bit. Even the miniscule bit of weight that piece had is, I doubt, enough to throw anything off balance.

JMO

[Leland Pate]

I had the same thing. I used a dremel tool and sanded down the area to relieve any stress fractures. It shouldn't be a problem.

[bigchillcar]

anybody know the max speeds these fans turn at? anyway, they don't spin like a centrifuge, so i'd agree, unless someone can state for a fact that this condition would cause premature alternator bearing failure. i wouldn't sweat it..but sure enough someone will post a horror story!
ryan

[Jascha]

Depending on your sustained RPMs -you could be generating a fair amount of angular momentum

Angular momentum = moment of inertia × angular velocity

L = Iw

[L - angular momentum (kg m2 s-1); I - moment of inertia (kg m2); w - angular velocity (rad/s)

Basically, at least two (fan pulley is smaller) rotations of the fan for every engine revolution translates to >>12,000 revolutions/min @ Red line (this may upset the alternator bearing some -on the Track)

[mb911]

thats an easy fix I just welded one up last week

[D'STARGA]

I guess I am just going to clean it up and reinstall it as is. I sounds like this is not that big of a deal. (I hope). Ben I would be interested in hearing about your fix on this. Thanks, Derek

[bigchillcar]

ben, did you use your tig welder for this? did you have the broken piece? i'm guessing derek doesn't have the chip that's missing..
ryan

[SC Schrauber]

Originally posted by mb911
thats an easy fix I just welded one up last week

just be sure to subtract the weld seam from the total amount of material to be added...


Seriously, don't worry about such a tiny piece. I 'm confident the Porsche engineers added enough tolerance to the fan and bearing.

[mb911]

The fans are magnesium and I did not have the broken piece I just built it up with weld. Most shops do not weld mag as it cost a couple hundred dollars per pound of filler rod so you may have to search around. I have been fixing these for several years for local p-car guys

after its welded up you just hand file it back to shape and you can blend with sand paper or what ever gets you fancy

[bigchillcar]

cool stuff, ben. guess you're the 'mag man' on the board.. we've got specialists here for everything.
ryan

[mb911]

Originally posted by bigchillcar
cool stuff, ben. guess you're the 'mag man' on the board.. we've got specialists here for everything.
ryan

I guess so!