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Discussion Starter #1
Just found this forum, and it looks like the place to get an answer to tricky questions. So, thanks to everyone in advance.

I've got a 1996 G20 that is having some interesting problems with dying batteries, and the usual suspects (battery, alternator) have been ruled out. I think it's a busted harmonic balancer that is not allowing the alternator to spin in tandem with the crank which is lowering output voltage. The quick questions are below, with a lengthy description following.

The questions:
Does anyone know 1) should the outer crank pulley ring spin freely when no belts are attached? (the inner pulley itself doesn't move, but the outer ring of the harmonic balancer spins by hand) and 2) does replacing this pulley require any specialized tools/knowledge?


The situation:
I'm going to go into a lot of detail in order to explain fully.

First off, last week my battery died while I was driving, but I was able to make it home and get it charged. I thought it was the alternator again (which I replaced just under a year ago) so I replaced it, but the battery still drains as I drive. I know that it drains because I ran some wires from the battery to my multimeter inside the car and watched as I drove, the alternator sometimes shows between 12 and 13 volts while driving, sometimes the battery voltage just drops gradually, it's all pretty arbitrary. Anyway, long story short, I have replaced my alternator (twice within the last week because I thought the first one was defective - 11.9V output w/ a 14.3V set point) and bought a new battery so that I can charge one while I use the other to drive around.

I know it's not the battery, as I have two that I'm using. One is brand new, and both charge and hold a charge well. I have gone through two alternators in the last week and have changed both v-belts recently. All belts are snug and in good shape. The second alternator showed 14.3V for about 50 miles, then dropped off to around 12V. No liquid (e.g. coolant) is getting inside the alternators.

Here's the main question: When I was changing a belt I noticed that the inner pulley of my crank stays fixed when the engine is off, but the outer ring spins freely by hand. That doesn't seem right, and because it's directly driving my alternator pulley leads me to believe that the outer ring of the harmonic balancer is not spinning in tandem with the crank pulley and that is causing the alternator pulley not to spin as fast as it should, giving me low output voltage to the battery. The alternator pulley does spin at idle (putting out between 12V-12.5V), but I can't comment on whether it is truly spinning at the crank speed, especially under load at highway speeds. I do notice that when I'm idling, my alternator voltage goes up by about half a volt versus normal driving.

Also, others in this forum have mentioned a squeal when they start their cars, and I have experienced the same thing. It usually only squealed for about 30 seconds and then stopped, but it sounds like this pulley could definitely have been causing the noise.

I'm comfortable fixing most anything myself (mostly out of necessity, I'm a broke college student) and have done quite a bit of work on this car, but never removed a crank pulley. Any help is appreciated.

Sorry for the length, but I'd rather give more info than less.

-Robert
 

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your harmonic balancer is shot. Get a new one and replace it. Common problem.

It's not suppose to spin freely. You need a puller to get it off. It can be done without one but don't bother. You will make it harder on yourself and cause more problems most likely. Actually a steering wheel puller works better then a balancer puller.

Use the screw to push the new pulley into place. Just line up the pulley and start torquin it down. Replace the seal behind there while your at it.

And please tell me you have a 5spd, otherwise this job is a bit more difficult.
 

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No it shouldn't spin, it is bonded with rubber to the inner part. Yours is broken.

You will need a puller, don't use bolts to press it off as you will destroy the oil pump behind the front cover.
 

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The harmonic balancer / crank pulley is two pieces of steel with rubber in the middle holding it together. The rubber allows some give to outter ring to allow its mass to absorb torsional vibration from the torque pulses from the individual cylinders firing. It should definitely not be freewheeling. If it freewheels, then it won't turn the alternator pulley, and the battery won't be charged.
 

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Discussion Starter #5
Perfect, thanks guys. I figured this was the place to go with something like this and I appreciate the help.

@Robkris - yeah, it's a 5 spd.
 

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Ok just put the car in 5th gear and have someone hold the brakes while unbolting the pulley. It's on tight so a good breaker bar or impact gun will be needed.

If it was an auto you would have to jam something into the flywheel. Not sure how you would get to the flywheel thought. I guess remove the starter?
 

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I removed the nut on my automatic by positioning the ratchet handle forward (pointed toward the front of the car, and cranking the starter. the pavement stops it and as the crank continues clockwise turns the nut right off. Dangerous to your tools, but not so much to anything else...worked like a charm for me.

Also, get an Unorthodox Racing underdrive pulley while you are at it...it is onepiece, and quieted down the vibration i got with the regular pulleys...plus it recovers some parasitic losses so the engine revs up faster. If you buy the two piece set, the water pump pulley is a snap to put on while you are in there. I've had mine for 30k miles - no problems whatsoever.
 

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I'm going to have to replace my pulley here in the next couple of days. What is the size of the bolt holding the pulley to the shaft? I don't have a wrench that large and will have to go buy one.
 

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I'm going to have to replace my pulley here in the next couple of days. What is the size of the bolt holding the pulley to the shaft? I don't have a wrench that large and will have to go buy one.
27mm or 1-1/16"
 
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