Rotational Play in Crankshaft Timing Sprocket

[gingerdyde]

When I grab my crank timing sprocket with the timing belt off I can rotate it very slightly on the camshaft. It makes a knocking noise when I do this. It's a very slight rotational play. It's not in the camshaft itself, just the sprocket.

Is this normal or do I have a problem? Or is this something that will go away when the harmonic balancer pulley is torqued down?

[xintersecty]

When I grab my crank timing sprocket with the timing belt off I can rotate it very slightly on the camshaft. It makes a knocking noise when I do this. It's a very slight rotational play. It's not in the camshaft itself, just the sprocket.

Is this normal or do I have a problem? Or is this something that will go away when the harmonic balancer pulley is torqued down?

oh man I got confused on reading your post. You mixed up the crank pulley with the camshaft pulleys. We need to know what year Aveo. The timing belt system changed on the 2009 engine.

The crank timing pulley held in place with sheer pin on the 2005-2008 engines. I don't know about the later version as I don't have one. Here is a picture of the pulley with the bolt on to move the timing. If the sheer pin is in place there is no play.

[gingerdyde]

Sorry, it's an 05 and I totally meant CRANKshaft sprocket. I had just typed a guide for changing camshaft seals so that's probably why I had camshaft on the mind. That's what mine looks like exactly.

Basically what I am saying is if I have the pulley bolt and belt off, but leave the sprocket on the crank I can slightly rotate the gear on the crankshaft. The crankshaft does not move, just the little gear has some rotational play to it.


By shear pin you mean the metal notch on the inside of the sprocket that sits into a matching grove on the crankshaft right? If so this is where I have play, it's almost like they don't fit together perfectly. The play is very minute, but enough to make a clicking noise if I jerk it rotationally with my hand. Is torquing the pulley bolt down going to remove this play or do I have bigger problems?

[jimzdat]

Definitely sounds like you have bigger issues - either the keyway in the crank is damaged, or the gear itself is damaged. If the crank is in good shape, and the key fits snugly in the slot, you should be able to get away with replacing the timing gear.
If the crank keyway is loose, start pricing out a new crank or a new engine.....

If you try and put it back together the way it is, you're going to be sitting on a time bomb...

[gingerdyde]

I ordered a new sprocket from Autozone. It should be here tomorrow. I will know by then whether or not it's just the gear or the crank. If it's the crank I think my girlfriend will just buy a different car. She's been talking about getting a different one since I started working on it. She loves this car, but the amount of work and time I have had to put into it has stressed her out. Plus she now has to commute to work so she's worried about the snow with the lack of ABS and traction control stuff that would be found in different cars. I told her it was because she didn't take care of it, but that's neither here nor there.

[gingerdyde]

This sprocket doesn't have a separate woodruff key like some engines. I'm sure you all probably know this already. Here's some pictures I grabbed for something else. Sorry for the blurriness, it was freezing.

[avguy]

I was completely puzzled by what you described in this thread, primarily because I don't recall ever reading a single report of this issue happening with an Aveo. And with the exception of a pulley bolt coming loose, I've never read an account of one of these keyed junctions breaking down on any other vehicle either. And from those pics that you just posted, there doesn't appear to be any sign of wear on either the key or the keyway.

My guess is that when the pulley isn't pinned in tight by the balancer bolt, there will be some very small amount of play. If the pulley can be slid off the shaft without needing to be forced off with a puller, then how can there not be some tiny amount of wiggle room? IMO it would be a huge mistake to give up on this Aveo just because of what you're finding with this pulley. I'd button it back up without a second thought if it were one of mine. JMHO, FWIW.

[jimzdat]

Now that we have some better pics, I'd tend to agree with avguy - despite my earlier comments. There will have to be at least some clearance in that fit; but it should be measured in thousandths of an inch - your original comment seemed like the thing was banging back and forth with a lot of slop in it, which would be very concerning. If there is minimal play in the fit, I'd say you'll probably be fine.

It's not like that gear is being asked to turn a 6-71 blower or something like that - so the stresses will be a lot less (although, that does paint an amusing mental image...)

[gingerdyde]

It was minimal play. Just enough to feel it, but not something you could really see visually. But it does make sense, all the other pulleys I have removed have been pressed on and I needed a tool. This one just bolts on and easily slides off, so it has to have some play. I just made sure I torqued the pulley bolt down to the given specifications of 70ft lbs + 30 + 15. That ended up being about 110 ft/lbs on my torque wrench when I was done rotating the 45 degrees. I think that's what takes the slop out of it.