Crankshaft Pulley Wobble

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Dtangard
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Crankshaft Pulley Wobble

Post by Dtangard » Fri Mar 18, 2011 7:53 pm

Today I took the crankshaft pulley off my miata to investigate a wobble and timing issue. I think the wobble is from my dampener but I'm not sure how to tell if the dampener is bad (besides seeing the wobble). Is there anyway to tell? It looks like the rubber is starting to crack.

I also noticed the 21mm bolt holding the pulley in place was much looser than it should be. I easily removed the bolt without much persuasion. Turns out it was so loose it destroyed the key and damaged the keyway. I replaced the key but was wondering if i could use jb weld to fill the gap between the key and keyway. Has anyone done this?

As always, any insight is greatly appreciated.
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Re: Crankshaft Pulley Wobble

Post by jadams » Fri Mar 18, 2011 10:35 pm

If the harmonic balancer is wobbling, then it is time to replace it. If you lose that part, kiss your motor goodbye. I broke three harmonic balancers before I invested some money on a good one, so I have seem the problems first hand. So do yourself a favor and replace it as soon as you get a chance.
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Re: Crankshaft Pulley Wobble

Post by John F » Fri Mar 18, 2011 11:21 pm

Agreed! You probably have had a wierd feeling at certain rpm's and the harmonic balancer was the cause. Replace it!
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Re: Crankshaft Pulley Wobble

Post by Stynger » Sat Mar 19, 2011 7:24 am

Dtangard wrote:Today I took the crankshaft pulley off my miata to investigate a wobble and timing issue. I think the wobble is from my dampener but I'm not sure how to tell if the dampener is bad (besides seeing the wobble). Is there anyway to tell? It looks like the rubber is starting to crack.

I also noticed the 21mm bolt holding the pulley in place was much looser than it should be. I easily removed the bolt without much persuasion. Turns out it was so loose it destroyed the key and damaged the keyway. I replaced the key but was wondering if i could use jb weld to fill the gap between the key and keyway. Has anyone done this?

As always, any insight is greatly appreciated.
Is this a 1990-1991 1.6? I've had very little luck fixing a keyway on the crank. :cry:
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Re: Crankshaft Pulley Wobble

Post by cfossum » Sat Mar 19, 2011 8:00 am

Stynger wrote: Is this a 1990-1991 1.6?
Aren't those the cranks with the nose that wobbles right before they break off?

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Re: Crankshaft Pulley Wobble

Post by Dtangard » Sat Mar 19, 2011 11:31 am

Stynger wrote:
Dtangard wrote:Today I took the crankshaft pulley off my miata to investigate a wobble and timing issue. I think the wobble is from my dampener but I'm not sure how to tell if the dampener is bad (besides seeing the wobble). Is there anyway to tell? It looks like the rubber is starting to crack.

I also noticed the 21mm bolt holding the pulley in place was much looser than it should be. I easily removed the bolt without much persuasion. Turns out it was so loose it destroyed the key and damaged the keyway. I replaced the key but was wondering if i could use jb weld to fill the gap between the key and keyway. Has anyone done this?

As always, any insight is greatly appreciated.
Is this a 1990-1991 1.6? I've had very little luck fixing a keyway on the crank. :cry:

Its a 1995. Have you done the loctite fix?
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Re: Crankshaft Pulley Wobble

Post by Stynger » Sat Mar 19, 2011 11:59 am

It more than likely had a timing belt done at one time and the crank pulley was not Loctited and torques correctly.

I've never done the so called Loctite fix. Being used as a race car, I have my doubts. I guess there is no harm in trying.
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Re: Crankshaft Pulley Wobble

Post by Dtangard » Sat Mar 19, 2011 12:53 pm

Stynger wrote:It more than likely had a timing belt done at one time and the crank pulley was not Loctited and torques correctly.

I've never done the so called Loctite fix. Being used as a race car, I have my doubts. I guess there is no harm in trying.
I think your right. When I removed the crank pulley the bolt was much looser than it should be. If I'm going to do the loctite fix should I pull the timing belt off to inspect the entire keyway? If the loctite fix doesn't work I need to order a short block right?
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Re: Crankshaft Pulley Wobble

Post by TroyV » Sat Mar 19, 2011 1:32 pm

You can always swap my old 1.6 in there.. :)
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Re: Crankshaft Pulley Wobble

Post by Dtangard » Sat Mar 19, 2011 1:40 pm

haha.. yea that might be the cheapest fix
TroyV wrote:You can always swap my old 1.6 in there.. :)
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Re: Crankshaft Pulley Wobble

Post by Stynger » Sat Mar 19, 2011 4:18 pm

Dtangard wrote:
Stynger wrote:It more than likely had a timing belt done at one time and the crank pulley was not Loctited and torques correctly.

I've never done the so called Loctite fix. Being used as a race car, I have my doubts. I guess there is no harm in trying.
I think your right. When I removed the crank pulley the bolt was much looser than it should be. If I'm going to do the loctite fix should I pull the timing belt off to inspect the entire keyway? If the loctite fix doesn't work I need to order a short block right?
The pulley is not the problem, just replace it. The keyway for the timing belt is the issue. If it's OK you're golden.
Remove the belt and the gear and check the crank.
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Re: Crankshaft Pulley Wobble

Post by TroyV » Thu Mar 31, 2011 10:33 am

How is it going Derek? Everything ship shape?
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Re: Crankshaft Pulley Wobble

Post by Dtangard » Thu Mar 31, 2011 2:10 pm

Unfortunately I haven't had a chance to work on it. I was on spring break when it happened and now I'm back at school for my last semester and I've been tied up studying for the FE exam. If I don't fix it in the next two weeks I might take my VW to the test and tune on the 21st. I'm itching to get back on the track.
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Re: Crankshaft Pulley Wobble

Post by Dtangard » Sat Apr 16, 2011 6:40 pm

So I changed the timing belt and did the loctite fix on the crankshaft. All seems good so far but there is a loud tick from the lifters I think. Should I change the oil, drive it for the day, and see what happens or could the tick be something else? The car sat all winter so I wasn't surprised to hear a tick.
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Re: Crankshaft Pulley Wobble

Post by nateh » Sat Apr 16, 2011 7:30 pm

Don't worry about it, they all do that.
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