Weird problem...need help!

94SubieSVX · #1 07-02-2007, 09:03 AM

Since i've got my first SVX(about a month ago)

, i've been trying to fix up the little things that are starting to go on the car. And everytime I drive it the crankshaft pulley bolt comes loose

. Even if i tighten it up right before i go driving it comes loose after about 10 miles. Its not extremely loose but it worries me. Can anybody help?? I don't wanna be driving and suddenly my belts blow off

Any input would be great

Thanks, Bill

94SubieSVX · #2 07-02-2007, 09:05 AM

Oh yeah i forgot to add, I put some lock tight on it last nite but didn't get to check it out yet.

svxfiles · #3 07-02-2007, 11:40 AM

Pull off your pulley, and check the crankshaft, the key, keyway, and the pulley.
see if anything is worn or bent.
And get back to us.

94SubieSVX · #4 07-02-2007, 11:43 AM

Will do. Thanks! -Bill

cdigerlando · #5 07-02-2007, 01:35 PM

How are you tightening the bolt? Do you have a special tool to keep the pully stable or are you just putting it in gear. Are you able to meet the torque spec? I don't remember what it is. Putting locktight on it is a good idea, but should not be necessary. I have never heard of this problem before? As Bill said, you should check the key way. I don't know how that would affect the bolt though, unless it is gone.

Sov13t · #6 07-02-2007, 01:37 PM

Quote:

Originally Posted by cdigerlando

How are you tightening the bolt? Do you have a special tool to keep the pully stable or are you just putting it in gear. Are you able to meet the torque spec? I don't remember what it is. Putting locktight on it is a good idea, but should not be necessary. I have never heard of this problem before? As Tom said, you should check the key way. I don't know how that would affect the bolt though, unless it is gone.

Fixed...

-ebil sov13t

svxfiles · #7 07-02-2007, 05:09 PM

Quote:

Originally Posted by Sov13t

Fixed...

-ebil sov13t

Thanks, Kirill.

Crank pulley torque spec; 108-123 ft/lb

I quick measured the crankshaft and the pulley at 23.7mm,
(outside and inside dimentions)
and the width of the key at 5mm.
It is not a loose fit!
If you use a 12mm socket on the "flywheel" nuts, attached to a long extention, say 22 inches, snaked under the intake manifold, that can stop the engine from rotating.

IF the key is rounded, worn, or missing, the crank pulley can move more freely to loosen itself.
If the pulley, or crankshaft is rounded off, or worn, that would not help either.
If the crankshaft snout seems bent, or out of round, the resulting vibration can cause the bolt to back off.
I would not want a 4000 rpm, 5 pound spinning disc to "get away"!

94SubieSVX · #8 07-02-2007, 11:20 PM

Quote:

Originally Posted by svxfiles

IF the key is rounded, worn, or missing, the crank pulley can move more freely to loosen itself.
If the pulley, or crankshaft is rounded off, or worn, that would not help either.
If the crankshaft snout seems bent, or out of round, the resulting vibration can cause the bolt to back off.
I would not want a 4000 rpm, 5 pound spinning disc to "get away"!

The only way I could think of anything being bent, rounded, or worn out might be because when I was talking to the previous owner, he had told me a while back that one of the belts just "snapped" off. Now if he was truthful and thats all that happened I don't think anything bad could happen because of that. But if what's happening to me happened to him and the pulley flew off that might be why its constantly coming loose. I haven't gotten around to taking the pulley off yet to check everything out, but I'll update tomorrow after I can take it apart.

Sov13t · #9 07-03-2007, 09:42 AM

I would imagine, if that pulley flew off before... you would see a huge hole in your radiator or at least the fans... also major dents and bruises on your car. So lets hope that wasn't the case

94SubieSVX · #10 07-07-2007, 07:56 PM

Found out the crankshaft pulley is warped and causing{hopefully} the bolt to keep coming loose...I was thinking about getting a lightweight new pulley. I've seen them before but don't know where to buy them. Anyone have a link?

svxfiles · #11 07-07-2007, 08:18 PM

Quote:

Originally Posted by 94SubieSVX

Found out the crankshaft pulley is warped

Bent?
How bent/warped is it?

94SubieSVX · #12 07-07-2007, 11:54 PM

When it is tightened, it wobbles up and down(like an oval) maybe 1/8", but when it's a little looser it wobbles alot more. Today when I started it up, it was idling around 600rpm. I think thats because of the pulley being loose.

svxfiles · #13 07-08-2007, 07:41 AM

Quote:

Originally Posted by 94SubieSVX

When it is tightened, it wobbles up and down(like an oval) maybe 1/8", but when it's a little looser it wobbles alot more. Today when I started it up, it was idling around 600rpm. I think thats because of the pulley being loose.

Can you remove the pulley to see if the shaft is bent/tweeked?
You can run the engine without the pulley,
briefly to check just the shaft.

94SubieSVX · #14 07-08-2007, 09:52 AM

I can do that. Would I just take the pulley off and start it up and check the crankshaft? I'm a newer mechanic and don't know very much about engines

svxfiles · #15 07-08-2007, 10:58 AM

Quote:

Originally Posted by 94SubieSVX

I can do that. Would I just take the pulley off and start it up and check the crankshaft? I'm a newer mechanic and don't know very much about engines

Yes, or you can remove the pulley, hook up a dial indicator, and slowly rotate the engine and check the runout.