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99 obw 2.5. tightened up a noisy ac belt two weeks ago. last night, both the ac belt and alt belt jumped off the pully (of course this happened at 1am). I bought two new belts thinking that maybe the original belt was off a grove and that caused it to jump. Im noticeing that the balancer has a distinct wobble at idle. this goes away at higher speeds. I checked the bolt and it seemed tight but did turn. any ideas? I know a small amount of wobble is considered normal but this is alot. bad balancer maybe?

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When they wobble the place the balancer meets up to the crank gear gets all rounded and domed. Also, if the keyway is buggered up, it might not be seating all the way.

Get a new one and make sure it seats up nice and flush to the timing gear. You don't actually need the keyway for the balancer, just torque it down good and tight.

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you need to fix this before the timing jumps and ends up bending valves.

 

replace the harmonic balancer, used is ok, and the key in the slot, new is best but any one in good condition will do. and then torque it to 140 ft lbs, (i trust emily that the spec is 127 ft lbs but i always go to 140.) replace the bolt if there is any doubt about it.

 

hopefully you can do this with out removing the timing cover, belt or the crank sprocket. but if not, plan on compressing the tensioner correctly and re-hanging the belt. i don't remember if oil or anti-seize is called for on the bolt threads. or how that might change the torque spec.

 

EDIT: there is a good thread on how to hold the flex plate / crank on cars with an auto trans while torquing the crank bolt, do a search. ''screwdriver flexplate'' i think will find it.

 

if the crank sprocket moves off of the correct timing mark far enough it can bend valves. this is an expensive repair compared to what you are looking at now.

 

ask here or put an ad in the WTB section for good used replacement parts. someone should be able to help for a fair price.

 

good luck and let us know how it turns out.

Edited by johnceggleston
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What does the timing sprocket have to do with the balancer?

The keyway won't come out unless you take the sprocket off, the sprocket probably won't come off with the belt in place because the belt will run up against the reluctor lobes and hold it in.

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What does the timing sprocket have to do with the balancer?

The keyway won't come out unless you take the sprocket off, the sprocket probably won't come off with the belt in place because the belt will run up against the reluctor lobes and hold it in.

 

in this case maybe nothing, but the action that loosens the balancer will, over time, loosen the crank sprocket. it will hammer on the key, the key way, and the sprocket until it moves off of the timing mark.

 

it sounds like he caught it early enough but if it were my car, i would take it down to the crank, and replace any and all parts that show abnormal wear.

 

i had a 93 that came loose over about 50k miles and eventually quit running when it was out of time. i had a local shop ''glue'' it back together with ''will never come loose'' loc-tite. after i wrecked it a couple of years later i bought a 95 and it too developed a crank pulley wobble. but i caught that one in time and was able to avoid any crank / sprocket damage.

 

his is a 99 interference engine, neither of the ones i dealt with were.

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i don't think they wobble or vibrate when they come from the factory. the only ones i have seen do that were in need of repair. but that is just my own experience.

 

You are correct: "wobble" is NOT normal for a crank pulley (aka harmonic balancer). They should rotate smoothly.

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ok ordered a balancer. should be here this weekend.car is parked in driveway and im not moving it. Ill replace the key and see whats going on with the crank. hopefully i caught it early enough. I have been thinking about how a failing balancer might throw off the timing and honestly i just dont get it. Correct me if im wrong ( i often am), but the balancer sits on the end of the crank ,flush against it. I understand the wobble will eventually mar the crank but how does the timing get thrown off? John, read your post and honestly just dont get it. maybe you could dumb it down a lil for me:confused:

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wow....this came as a surprise!! I wanted to get a look at the crank to see what kind of damage i had. Took off the drive belts, but a chain wrench on the pulley, and started to loosen the bolt. The bolt turned very very easily!! Oh god, i somehow stripped the bolt or crank! Then, the entire top metal grooved piece of the balancer came right off!! I was turning the metal piece!! The rubber had totally disconnected from the metal pulley! How this thing didnt come flying off and plow thru my radiator I just dont know.

Im thinking when i took the motor apart last summer, i used the chain wrench to break the crank bolt. It worked great but if you think about it, that would put tremendous strain on the rubber bonded to the pully. I think this loosened or tore some of the rubber away, and miles did the rest My own theory. who knows. Anyway, the crank, key, and bolt are not involved. I need a new balancer. Good news!

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in this case maybe nothing, but the action that loosens the balancer will, over time, loosen the crank sprocket. it will hammer on the key, the key way, and the sprocket until it moves off of the timing mark.

 

it sounds like he caught it early enough but if it were my car, i would take it down to the crank, and replace any and all parts that show abnormal wear.

 

i had a 93 that came loose over about 50k miles and eventually quit running when it was out of time. i had a local shop ''glue'' it back together with ''will never come loose'' loc-tite. after i wrecked it a couple of years later i bought a 95 and it too developed a crank pulley wobble. but i caught that one in time and was able to avoid any crank / sprocket damage.

 

his is a 99 interference engine, neither of the ones i dealt with were.

 

I currently have a '96 Legacy L at my shop that this happened to. Crank sprocket moved considerably on the crank, damaging the key way in the crank, the sprocket and the pulley.:eek:

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Found a 2.2 balancer at the junkyard. This is exactly the same size. Miced the crank hole, anyway, overall width, and thickness. Has two groves for serpentine belts just like the old one. Only diff. Seems to be less rubber . Any reason I can't use this?

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when is a slight vibration a not considered normal?

i don't think they wobble or vibrate when they come from the factory. the only ones i have seen do that were in need of repair. but that is just my own experience.

You are correct: "wobble" is NOT normal for a crank pulley (aka harmonic balancer). They should rotate smoothly.

 

What if it's more of a slight twitch?? So slight it doesn't show up on a video I took of it

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There may be some slight movement of the outer part, even if it's still good. Very slight though. This is ok ONLY if it's the OUTER part moving. The inner part should not have any noticeable movement.

This video clearly shows the entire pulley moving.

which is bad.

 

Now, if the outer part moves a little, mark it with some white paint. Mark it all the way across both the inner and outer sections, that way you can see if the outer section is slipping.

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There may be some slight movement of the outer part, even if it's still good. Very slight though. This is ok ONLY if it's the OUTER part moving. The inner part should not have any noticeable movement.

This video clearly shows the entire pulley moving.

which is bad.

 

Now, if the outer part moves a little, mark it with some white paint. Mark it all the way across both the inner and outer sections, that way you can see if the outer section is slipping.

These are the videos I took earlier:

 

like I said, very slight

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just want to wrap this thread up. I used a junkyard 2.2 balancer and it works fine. the original balancer had come apart and was throwing belts. This all might have turned out to be a good thing. I had originally torqued that crank pulley bolt to 100ft lb as per haynes. After reading a few threads, i cleaned the bolt threads, lite coating of antisieze, and torqued it to 140. thanks to everyone who answered.

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