[Steveorama]

Th key that is bent should not be the same key that hold the harmonic balancer. There is a shaft seal in the timing chain cover and that seal needs to be on a smooth surface. The balancer gets put on after the timing chain cover is on. That is why I am thinking that maybe the crank sprocket is on backwards..

I have not taken apart the timing chain and related parts on an ecotec engine yet. so I am not sure how the parts are supposed to sit. But this is what is coming to mind, If you took a section view of the crank sprocket would the teeth be exactly in the middle of the sprocket, or are they offset to one side? If they are offset to one side an the sprocket is put on placing the teeth to close to the block it could cause the balance shaft chain sprocket to move inboard as well leaving the key partially sticking out..

Or does the timing cover shaft seal not seal against the crank and instead it seals against the harmonic balancer. If that is what it does then someone may have taken the balancer off and when it was not put back on they didn't realign the key to the balancer and then they were torquing the bolt down it made a disaster of the key. Now the key may have temporarily held the balancer but at some point it would have moved and that would have caused the balancer to end up with a loose bolt.

There is a difference between the 2.4 and the 2.0 crank sprockets, I don't know what the difference is. It could be the number of teeth, it could be the thickness... not sure.

This could have been caused by some ding dong at the factory not putting the balancer on properly. hell 1/2 the bolts holting my exhaust manifold on I was able to take out with my fingers, not tightened at all same thing goes for the bolts holding the turbo to the manifold. I lost 2 of the 3 bolts holding the driver side front wheel bearing. I cannot even tell you how many bolts I have come across that were only finger tightened. So I would not be the least bit suprised if GM did this at the factory.

The crank sprockets and the balancer all utilize the same key on the crank. The timing cover has an opening with a seal that the balancer goes through and seals against the balancer.
Here is a pic of mine before installing the gasket and timing cover a couple weeks ago. I didn't get a pic of the cover mounted before the balancer was mounted or of the balancer prior to reinstallation.

The inner crank sprocket for the forced induction engines mounts with the timing marks facing out and it has two notches on either side along with the GM part number. Here is what it looks like.

The N/A engines utilize a thinner sprocket that looks like this that came with my Cloyes kit that I didn't use. Note: I did not measure the difference between the two, but the width is noticeably wider just by looking at the two side by side.

Both sprockets have teeth that are more or less centered on the sprocket and should only be mounted with the front facing out for proper alignment.

My suspicion is that someone pulled the balancer for whatever reason and then didn't get it back on the key. There isn't much key to mount to as seen in the picture and unless you pulled everything in front of the engine you're more or less doing it by feel so it's fairly easy to push in the balancer and assume its on and then tighten the bolt. It takes a few wiggles to get the balancer on the key the correct way and it's a noticeable difference when you do as the balancer slides back another 1/2 inch or so and no longer turns left or right.

 

[pscartozzi]

My suspicion is that someone pulled the balancer for whatever reason and then didn't get it back on the key. There isn't much key to mount to as seen in the picture and unless you pulled everything in front of the engine you're more or less doing it by feel so it's fairly easy to push in the balancer and assume its on and then tighten the bolt. It takes a few wiggles to get the balancer on the key the correct way and it's a noticeable difference when you do as the balancer slides back another 1/2 inch or so and no longer turns left or right.

I think this is right.
Watch this video starting at the 5:30 mark

 

[Steveorama]

I think this is right.
Watch this video starting at the 5:30 mark

That’s exactly what I was thinking happened looking at the damaged key in the first post. Good find on the video that shows what I was thinking pretty well.

 

[kgschlosser]

I am willing to bet then when someone put the balancer on they didn't have they key lined up and the key got bent probably when they put an impact gun on it to tighten it.

 

[Hoosier GXP]

Th key that is bent should not be the same key that hold the harmonic balancer. There is a shaft seal in the timing chain cover and that seal needs to be on a smooth surface. The balancer gets put on after the timing chain cover is on. That is why I am thinking that maybe the crank sprocket is on backwards..

I have not taken apart the timing chain and related parts on an ecotec engine yet. so I am not sure how the parts are supposed to sit. But this is what is coming to mind, If you took a section view of the crank sprocket would the teeth be exactly in the middle of the sprocket, or are they offset to one side? If they are offset to one side an the sprocket is put on placing the teeth to close to the block it could cause the balance shaft chain sprocket to move inboard as well leaving the key partially sticking out..

Or does the timing cover shaft seal not seal against the crank and instead it seals against the harmonic balancer. If that is what it does then someone may have taken the balancer off and when it was not put back on they didn't realign the key to the balancer and then they were torquing the bolt down it made a disaster of the key. Now the key may have temporarily held the balancer but at some point it would have moved and that would have caused the balancer to end up with a loose bolt.

There is a difference between the 2.4 and the 2.0 crank sprockets, I don't know what the difference is. It could be the number of teeth, it could be the thickness... not sure.

This could have been caused by some ding dong at the factory not putting the balancer on properly. hell 1/2 the bolts holting my exhaust manifold on I was able to take out with my fingers, not tightened at all same thing goes for the bolts holding the turbo to the manifold. I lost 2 of the 3 bolts holding the driver side front wheel bearing. I cannot even tell you how many bolts I have come across that were only finger tightened. So I would not be the least bit suprised if GM did this at the factory.

The chain sprocket is in the correct position, if you were to turn it around you could not get the chain to align properly, mostly what your are seeing is just the camera shot angle making it look to be close. 2.4 engines actually have a different chain sprocket ( it is not as thick) than the 2.0 but use the exact same chains, guides and tensioners.

 

[kgschlosser]

as was posted i that video someone probably put the crank pulley on and didn't align the key and when they discovered they were chewing up serpentine belts out cam the impact to crank the pulley in tighter so the belt would ride properly and in doing so the key got all bet to hell.

 

[marksbug]

timing chain guide question,,, has any body seen any after market guides take a dump? china or cloyes or melling? any body got feed back on the china chains and how much they stretch? also...I wonder if the balancer not being fully back when the key was bent thus not against the sprockets so the sprockets were"loose" and not pinched between the dampner&crank shoulder, .could that of been the cause of guide issue & premature chain flopping around?