Bad Harmonic Balancers?

D50boy

Member
:
2002 Protege5 beater edition
Has anyone here encountered an issue with their harmonic balancer/crank pulley twisting?

I've had my P5 for about a year and a half as a beater. It has really needed some work. In the time I've had it, I've found that just about anything made out of rubber has gone to crap. Motor mounts and suspension bushings mainly. This past weekend, I decided to check on the timing belt since I had 184k on the clock and had no idea if it had ever been done, plus I've had bad engine vibration. It turned out my T-belt was fine, but the tensioner and spring were wasted, so I decided to do the whole kit- water pump and all. When installing, I put the #1 cyl at TDC on the compression stroke by removing the spark plug, turning the crank pulley bolt until by thumb is pushed out of the spark plug hole from the compression. From there a screwdriver down the hole gives me a visual on where TDC is. In looking around at the manual later, I see that the harmonic balancer has a yellow tick mark which SHOULD line up with the "T" marking on the timing case, which is at about 11:00 when looking at the pulley bolt. At TDC, that timing mark of mine was at 3:00. Way off! I visited the junkyard and found two Protgs which had the FS motor. One had no timing mark (wtf) while the other had the mark at 1:00, also off from where it should be. I'm guessing that the rubber inside of the Harmonic Balancer has rotted out (just like the rest of the rubber on this car) and allowed the whole thing to twist. Since these are supposed to be balanced, I'm guessing the twisting has thrown the balance off, causing my engine vibration. Has anyone encountered the same thing? It seems odd that the junkyard car had tick mark out of place like the one on my car, could this be a chronic issue?
 
I'm pretty sure we don't have a harmonic balancer because we have an in line 4 and it's balanced by design.

But the crank pulley needs to be properly aligned to allow the crank sensor to get a proper reading.
IIRC, the crank pulley has evenly spaced teeth on it with one missing tooth to let the ECU know where it is in it's rotation.

I believe my pulley is solid metal with a keyway to provide proper alignment.(it's been a while since I did my T-belt)

I assume you used the timing marks on the timing belt pulley to set your valve timing or your car probably wouldn't run at all being that far off.

A lot of guys install after market under drive pulleys which could explain the difference your seeing,.. Maybe the rubber too.

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You could go with a lightened crank pulley or underdrive lightened crank pulley and eliminate any concern over any issue with aging rubber since they are solid aluminum. There are several brands. I'm running and Unorthodox Racing one. Also lightened wp/alt/ps pulleys. Been issueless for a decade.........

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Yes, the cam and crank sprockets are all perfectly aligned now. Its just that timing mark isnt where it should be. The crank shaft pulley teeth are still lined up s they should be. The keyway on the pulley lines up with the toothy disk (there is a drilled dot on that piece. The car runs, but it doesnt run smoothly. In looking at the stock pulley, it does have rubber in it. The face of the pulley also has holes drilled out for balance. This cant be a solid piece of metal. Im not sure about a set of underdrive pulleys.... unless I find a set for a deal.
 
... It’s just that timing mark isn’t where it should be... The car runs, but it doesn’t run smoothly...

What I'm thinking is that the ECU doesn't know where the crankshaft is, creating stumbling problems... ???

Your missing tooth is off by up to 40

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This is what Ive got:


You can see the keyway points to the hole in the toothy disk. That hasnt shifted at all. Its that timing tick mark.

This is what it should look like:

 
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I went out to my parts car to look at my pulley and I couldn't see any rubber... Unless it's hidden under the pulley bolt???

It looks like the toothy disk is attached to the pulley...
I don't see how the pulley can shift without taking the toothy disk along with it ??
 
i don't know about the mazda one specifically in our cars (it's been 60k miles since i replaced my timing belt and i didn't pay attention) but most crank pulleys (harmonic balancer) are an outer pulley (with the grooves the drive belts ride on) suspended by rubber around the pulley center (driven by the keyway). Over time the rubber can degrade and the outer pulley separate from the center section.

having said that, while it is possible this could cause an engine vibration, it wouldn't be much or very noticeable. many people will put on an underdrive pulley and eliminate all the rotating mass of the stock pulley all together and don't notice any additional vibration. having said that, if yours is separated you should replace it with either another one or an aftermarket one. As it continues to deteriorate it will eventually allow the inside portion to turn and the outside that turns the drive belts won't spin at all and you'll have no alternator, pump, etc. i've actually seen these separate completely and come flying off and across the parking lot at about a million miles per hour. This could potentially cause damage to parts inside your engine compartment as it bounces around in there trying to come flying off and out.
 
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So is the toothed ring attached to the pulley and would having it out of proper sync/alignment give bad data to the crank sensor and make the car run crappy ??
I would figure the orientation of that missing tooth is important.
 
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I went out to my parts car to take a picture of the crank pulley and finally noticed the rubber. (I was looking in the middle before)

I don't know if the toothed ring is attached to the inside or the outer pulley though ???

If it's attached to the outer pulley then the toothed ring would shift along with the pulley.

As pb4ugotobed mentioned, you should replace the pulley..
The timing mark is really only for ignition timing but if it's slipped, it's one step closer to rocketing out of your engine bay.

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So just to over think it a bit more...

As D50boy mentioned and the picture shows, the pulleys are drilled to balance the whole pulley.
I could see a shifted pulley throwing off the balance causing vibration.
 
having said that, while it is possible this could cause an engine vibration, it wouldn't be much or very noticeable...

I dunno ???
This pulley has three drilled holes... That's a lot of meat.

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The toothed ring doesn't look attached to the middle but it's probably not attached to the outer pulley either... Just the rubber, so the pulley can slip without pulling the sprocket with it...

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I dunno ???
This pulley has three drilled holes... That's a lot of meat.

Yes that is a lot of meat. However the metal removed from those 3 holes is not a lot of weight in comparison to the entire weight of the pulley. A gram or two compared to at least 2 or 3 lbs for the assembly. more likely the vibration is caused by something else... wheels, tires, bad axle, ball joints, coil pack/misfire (even if not a total misfire a partial miss can cause a "vibration" feeling, dirty throttle body if at idle, cheap/crappy motor mounts, misaligned motor mounts, etc. He didn't specify the conditions of the engine vibration he just said there is one. Due to the vagueness it would be hard for me to condemn the balancer as the root cause.

IT very well could cause what he's experiencing. I have just been in too many cars (Toyota's granted...) with bad balancers and the vibrations is barely noticeable unless you're REALLY picky. I'm just saying that I wouldn't be quick to blame this for a vague interpretation of a vibration. However, if the rubber is deteriorated and the outer has turned from it's home point, it needs to be replaced or that thing could do some pretty significant damage to the vehicle and could be pretty dangerous to pedestrians if you're driving down the road next to a sidewalk or a busy street when it decides to let loose. The last one i saw fly off was in a jeep grand cherokee and it was in our back lot... thing took off like a rocket when it dropped out and blasted off into the bushes and trees a few hundred feet away. We never found it!
 
Well either way, he should get a new pulley... Maybe he'll let us know if it stopped the vibration.

PS... If you get an under drive pulley, you'll need to get shorter belts and your alternator will slow down making it struggle even more to put out power.


... The last one i saw fly off was in a jeep grand cherokee and it was in our back lot... thing took off like a rocket when it dropped out and blasted off into the bushes and trees a few hundred feet away. We never found it!

That would make an awesome video !!
Take your vehicle to the middle of nowhere and let er rip !!
Red Neck Ring Toss !!
 
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