Sheared key in fan hub. Options

[Jesco Reient]

So I was trying to change the seal on the fan Hub, Big leak, when tring to remove the fan hub from the crank it required a puller and an indordinate amount of pressure to break free. Once it had broken free I found that the crank keyway had sheared and was in two pieces. This had happened prior to our buying the car but is one more thing that has shown up during the Tune-Up (IMG:style_emoticons/default/headbang.gif) and leak fix that keeps growing with leaps and bounds (IMG:style_emoticons/default/chair.gif) . any Ideas on cause?

[timothy_nd28]

Man, I would love to see a picture of this!

[Cap'n Krusty]

The keyway is the slot in the crank, the key is the little half-moon steel piece that sits in the keyways (one in the crank, the other in the hub). Buy a new key, see how it fits in the 2 slots. If it's a tight fit in both, clean the surfaces and put it back together. If it doesn't fit tight in the hub, get a good hub. If it's loose in the crank, you're SOL, the crank should be replaced. As for the hub being Inordinately tight, it's a taper fit, and it is supposed to be REALLY difficult to remove. If either tapered surface is bad, replace the bad component(s). The key locates the hub for timing purposes, the bolt secures the hub axially, and the taper secures the hub in place. Any wear in any of the components renders the assembly at risk if failure. PS, don't forget the o-ring.

The Cap'n

[infraredcalvin]

Are you taking about the woodruff key insert on the end of the crank? Can pick a new one up at local auto parts store. As for cause, stress and cheap material???

[rnellums]

I had this happen to me during a road trip. basically the fan was not not mounted square to the crank during a rebuild by yours truly and the imbalance led to the sheared woodruff key. If you are lucky the keyway in the crank will not be marred. If it is, you will need to fix it properly and install in a new crank. I was able to extend the life of mine enough to get me home by cleaning the assembly well, filing down the edges, replacing the woodruff key, and finally filling all the voids with epoxy before torquing the assembly back together. This let me make it the next 600 miles home, and is still holding together to this day, but it is not "fixed".

Pictures:

[Jesco Reient]

Mine was not that badly galled, it was a clean shear and the key came out in two parts. The fan is missing a blade so I'm thinking really unbalanced? or maybe the PO had an alternator lock-up and seized the hub? really soft non-standard key? I don't know.

Cap'n Which "PS, don't forget the o-ring"? are you talking about? more possible "Mekanik werkins" from the PO? Who needs thisitis?

[Cap'n Krusty]

The o'ring goes behind the hub when you install it. You'll notice a step on the back; that's for the o-ring. I doubt you's EVER find the woodruff key in a FLAPS, so you might want to order one from a Porsche or VW oriented shop or parts source. GPR might have one. Just make sure everything is clean and not chingered up and you should be OK. Use the correct thick washer and special bolt, torqued to 18 ft/lbs.

[Jesco Reient]

The o'ring goes behind the hub when you install it. You'll notice a step on the back; that's for the o-ring. I doubt you's EVER find the woodruff key in a FLAPS, so you might want to order one from a Porsche or VW oriented shop or parts source. GPR might have one. Just make sure everything is clean and not chingered up and you should be OK. Use the correct thick washer and special bolt, torqued to 18 ft/lbs.

Thank you very much for pointing out the "O"ring behind the fan hub, the people that were in there before had not used one. I have a new key from Deutschland and am going out to try it in place now. does the "missing "O" ring come in a standard engine kit?

[reharvey]

I had this happen to me during a road trip. basically the fan was not not mounted square to the crank during a rebuild by yours truly and the imbalance led to the sheared woodruff key. If you are lucky the keyway in the crank will not be marred. If it is, you will need to fix it properly and install in a new crank. I was able to extend the life of mine enough to get me home by cleaning the assembly well, filing down the edges, replacing the woodruff key, and finally filling all the voids with epoxy before torquing the assembly back together. This let me make it the next 600 miles home, and is still holding together to this day, but it is not "fixed".

Pictures:

Wow! That is a mess! Surprised it's still holding together. I've had my share of problems with impeller fans. I've found that it's best to use one that has never been disassembled. The alt. pulley is difficult to alien with the fan and wobbles around causing all kinds of problems!

[wndsrfr]

. any Ideas on cause?

As to the cause:
Mine had the alternator belt work loose, spin off of the alternator, twist into a figure "8" and hang up on a bolt while flopping around, bringing the engine to an immediate halt. (OK, this was all helped along by an off-track at turn 1 Summit Point after overcooking the entry.....but I digress) Actually didn't shear the key, but certainly could have. It just pranged the allen head bolts holding the fan to the hub enough to screw up the timing (I'm on SDS with magnets in the backside of the fan) and lead to lean running, engine failure and a rollback ride costing $150 for one mile of transport. (IMG:style_emoticons/default/headbang.gif)

[Jesco Reient]

So for everyones information the key fit nicely, the Fan hub was replaced due to the finish in the bore, the crank was fine with a very little stoning. The new seal was installed with Lubriplate to protect it during start up. and now I'm checking the end play and replacing the rear seal. The "O" ring was in the gasket kit.

Thanks to everyone especially the Cap'n for telling me about the "O" ring.

(IMG:http://www.914world.com/bbs2/uploads_offsite/carphotos3.cardomain.com-14690-1349795522.1.jpg)