ZombiePorsche44

Robin, I wasn't suggesting a factory fresh one, I was just suggesting a whole one.

I had a fan come apart at a DE event while revving at around 5000rpm and the fan and housing were destroyed and both had to be replaced as well as the alt/gen.
In my case the fan hub cracked then exploded, the sound was unbelievable, first a quick 150+ decibel giant screech (people said they heard it at the other end of the track approx 1 mi away) then an really huge bang and the sound of metal shards flying all over the engine compartment.

Hope none of you ever hear that sound..............ZP44

Fred, Long Island

JB's Weld It will hold up. Looks will depend on how well you fare it in and trim off excess. Stuff actually repaired a hole in a former transmission, it works on the engine case as a plug sealant, so in this location, it should be fine. No guarantee...depending on your expertise. I'd suggest a little extra dab on the inside edge.

Greg Fishman

Was this on your 993?
Never heard of that type of failure before, and am glad for it.

ZombiePorsche44

No Greg it was my old 1979 911SC 3.0L, evidently when I had the fan out of the car it was somehow damaged on one of the bolt holes (crack) and when it had enough rpms, it let go, the screech was when it hit the housing at speed and the bang was when it came apart and penetrated the housing destroying the alt/gen bearings too.
It wasn't cheap to fix, but I have never heard of another so I wouldn't lose sleep over it.
ZP44

eloyex

the mass of the whole unit is hundred times bigger than the broken tip, so you should have no problem leaving that way .... in the meantime open your eyes at ebay for another one ...........

eloy

Porscheologist

This happened to me on a previous Porsche. I "filed" a small amount off the opposite fan to balance it, smoothed out the the chipped blade, put it back on and forgot about it. No issues. Or you could go out buy a new one, powder coat it a cool color (RED) and put it on. All depends on your wallet size I suppose.

ZombiePorsche44

Fred is right about JB weld....I remember Ken Rumbaugh from Scotts Porsche in National City once stripped out a sparkplug in his old 4cam 4banger 914 at a Willow Springs POC Cup Race weekend, we slapped JB weld around the plug threads, put it back in the car and let it cure.
We started the car for the next session and it didn't leak! We were able to run the rest of the weekend without a problem.
The only problem was, when he got it back to the shop and got the heads off, the plug had become a permant part of that head and the entire head had to be junked for a new one.

That's Racing...................ZP44

Robin 993DX

Thank you guys for all of the repair idea regarding my damaged fan blade.

I decided to go with the epoxy route, did a dry run when the stuff dried it was very hard couldn't even chisel it away. So.....

Porscheologist

Yikes! Hope it comes off when the lid is closed. As an Engineer I would not recommend ever standing inline with that fan for any reason while that car is running.

You have just created a serious safety issue for the sake of looks my friend. Be sure to check it often as many expoxies do not do well with heat cycles (thermal stress at the bond joint as the magnesium expands a different rate). Seriously if that thing comes off at 6,000 RPM you not be happy with the result.

tj90

Robin:

Dont worry about the chip. As far as the chip flying off - its in a cowl so it will rattle a round a bit before its shot back to the alternator. Remember the clearance of the blades is not that much and you run the risk of damaging other blades. If you are really concerned about balance (I dont think its mush of an issue. Drill out a piece on the inner portion close the the axis - you can see where porsche did this for balance. You should not have to remove that much material....

ZombiePorsche44

Robin,
The fix looks good but should you hear that horrible screech shut her down instantly or you'll be buying a new alt/gen & fan.
ZP44

Robin 993DX

Ok, so you guys put some fear in me so I tried to break the epoxyed chip just to leave it off.... And for the life of me I couldn't break it off...... Damn it!

Caution about where you stick that epoxy.....

tj90

The chip is toward the rear of the fan so maybe it wont lodge between the fan blades and the cowl. If you cant remove it, maybe its best to leave it...

Fred, Long Island

Leave it...first, it's subjected to a tremendous amount of airflow during operation, keeping it cool. At shutdown, it should hold (epoxy) with the residual heat seeping by. You can easily monitor it by checking periodically to see if you can, indeed, break it off. If so, it was ready to go. I doubt you'll have any problem. You'll soon stop losing sleep over it.....Just insure there's no high spot that hits the housing. If you have the strap clamp off the housing...do not, repeat do not tighten it too far, it compresses the housing and could cause a reduced clearance withing the housing with the blades clicking or at worse impacting the housing. Just a few tips learned the hard way. Good luck.

faster

Robin, keep an i eye on it. i agree with alex and i think i might have advised you not to glue it back on. i know its a problem in my industry and i know its no f-16, but with the high heating and cooling cycles of the fan blades and the glue, it is possible it can weaken its bond and become a projectile and you might end up with more damage than just a cooling fan with a chipped blade. Also worn alternator bearings or overtightened fan belt can cause the blades to rub the shroud witch might innitiate its departure. just a heads up, good luck.