Crank Pulley Wobble - more than meets the eye!

[n2x4]

So I decided to start working on my spare legacy. It had bad hesitation up to 3k rpm, and it would barely move in gear. I removed the crank pulley and this is what I found:



You can see that the crank pulley bolt had loosened up and the key ate away at the pulley. But wait, that's not all! I found that the key itself was twisted a little, and sticking out sort of sideways from the crank gear. I had to use a puller to get it off. Here's what it looks like:



You can see that the keyhole is a little chewed up.



Let's not forget about the crank!



And another shot for fun:



Last and least, this is what the key looks like after it had it's fun:



So that's it. Basically I'm hoping that I can weld a new key back into the crank and file it down so a new gear and pulley can be installed. Let this be a lesson to everyone - check your crank pulley bolt! Also, you may want to stay away from purchasing a suby with crank pulley wobble. This one cost me $500 bucks, and turned out to be slightly more serious than I anticipated.

Talking to the local subaru yard turns out that a bad crank pulley is a common problem, as they have a shelf full of replacements.
I've read the threads that already exist on this, and decided to document my progress with some pictures.

[Bheinen74]

its because the Subaru Fuji Service manual says to torque the bolt to like 70ft lb, when it is supposed to be 125 ft lb ???
so, that is why Subaru has had a problem here....

[shtbxr22]

Well, that looks like my crank/pulley/key/sprocket. Mine was wobbling as well when i got my 92 leg turbo a month ago for $400 bucks. Just fixed it yesterday by filling some of the keyway with weld, shaping to fit new key, new sprocket, and pulley. Oh yeah, did I mention that the jerk that had the car before me put in like three pounds of loctite in with the crank bolt!!!!! Upon removal of the bolt, about one and a half inches of bolt was left behind So, i angle grinded a monster bolt head, fit it into the crank very straight carefully, welded it in, cleaned it up pretty, put the new pulley on and now instead of a bolt, it uses a stud-like setup. Works great.

[n2x4]

I plan on welding it back up, and may just reuse the old sprocket and weld it on as well. It doesn't need to come off ever anyways, plus then all I'd need to buy would be a new key (sure I can find one in the garage anyways). I'll price a new crank gear just for fun though.

Thanks for your input, and welcome to the boards!

[ericem]

Acually, subaru told me to torque the bolt to 140ft-lbs, but i dont have the fancy tool to hold the pulley, but a pulley holder, its like a belt that wraps around the pulley, but me and my dad could only get it to 100ft-lbs, so i drove it to my great local subaru dealer 40km away , and got a oil change, and they torqued the bolt to 140ft-lbs and i watched them. and they sticked the 4 bolt tool into the crank pulley.

[realfinn]

Is it the fact that its suposed to be torqued to a higher amount or is it the fact that it needs thread locker or the bolt. I noticed that the manual didn't say anything about it.....I have never put a pull back on a motor and not used thread locker.

[shtbxr22]

Subaru says 135 ft. lbs plus or minus a few lbs, but I like to do just a little drop of red loctite......hasn't failed me yet. I do one at least 5-6 times a month.