No worries about the lack of pics, what you've already uploaded is really helpful. A very interesting question here is if I'm actually running the wrong bolt, AND my sprocket is "close enough." Ha, what a mess.

So I may be a little excessive with my half tooth estimate. I guess what it comes down to is that I could feel definite play, and as you say, I was expecting none at all. Even if my bolt does turn out to be wrong, I really want to deal with that sprocket.

Well, that sounds like more than enough convincing to leave that seal alone. I'd rather not repeat your crankshaft experience!

Jay - I think the bolt in the photos 1100A022 is the 3.0L part number.... 1100A141 is the 3.5l/3.8l

phl,
I believe you are 100% right about that. Come to think of it, when I ordered the crank bolt for the 3.5L engine overhaul, I simply reordered the same crank bolt from my 3.0L engine overhaul from 6 months prior.

Dang, my mistake. I didn't realize there was a difference. I really aught to contact the new owner of the 1997 Montero. I want that thing to stay on the road and if it goes down because I made a mistake, that will make me feel responsible. Thanks for pointing that out.

I'll get a hold of him right away. poolecr, take my photo of the pulleys and my crank bolt with that grain of salt. That was my mistake and a good catch by phl.

Good catch! At least that clears up my confusion, glad I've got the right one after all.

Hopefully you can get in touch with the owner Jay. Though with some luck there's still plenty of thread engagement. If it took the full torque I'd like to hope that it will stay put.

Is it the outer ring wobbling of the entire damper? From what I can tell, the assembly indexes / datums axially on the OD of the timing sprocket and is held square by its face.

If your sprocket was loose, you could have a problem(EDIT for clarity: ID of pulley or OD of crank).

Another test would be to check the runout with the motor off. If you take the pulley back off again, look for fretting marks to see if its moving.

The outer ring will move in response to engine harmonics, but its not supposed to wobble.

Sorry about that I didn't know what your dealing with.
My suggestion to look at the engine side of the pulley was because I thought at first you were unsure if it was wobbling or just an illusion. Now I see that was about an rpm change making it better or worse..
Ill leave you to the more experienced.
Hopefully it is something small. Sounds like it is, good thing you caught it.

The entire pulley appears to be moving. It's pretty subtle, and I did actually put a few hundred miles on it before I caught it. But since I noticed it and talked to you guys, I'm thinking the sprocket slop has allowed it to be tightened down slightly off kilter. I don't THINK it's actively moving on the shaft, but once I have it apart I'll check for signs as you recommend.

Any hints you can give me for testing runout? Haven't done that before but I'd be curious to check it on this motor.

I've FINALLY returned from my work trip, after it was extended repeatedly... Fun! Time to get back to solving this Montero issue.

I didn't get much done today, but I did pull off the accessory belts and fan so I could get some video of the balancer and crank pulley bolt. The links for all the videos are below.

Not sure anybody will want to sit through all of them, but they do show how unpleasant the issue is ("Angle" and "Closeup" particularly). And yes, in retrospect I want to kick myself for doing such a bad job holding the camera still. I was doing a bit of contortion to get it in there without dropping it into the balancer... tomorrow I can try to get better shots if they will be of value.

Overview
Angle
Bolt Closeup 1
Bolt Closeup 2

My main concern as shown in the "Angle" and "Bolt Closeup" videos is that it looks like the bolt itself is wobbling as well as the balancer. (Unfortunately the YouTube processing seems to hide this somewhat. They've also thoughtfully rotated the video 90 degrees for reasons beyond my understanding.) Anyway, I'd thought that at least the bolt itself would be true.... Does the fact that it wobbles as well hint that there's something wrong with the crank? <img src="/forums/images/graemlins/scared.gif" alt="" />

Tomorrow I'll probably pull it apart down to the timing belt to do further investigations of the sprocket, snout, and key as mention earlier in this thread, but I wanted to get this video up first and see if you had any thoughts for other tests I should do to diagnose.

Well, I've found some answers. Not sure how I missed some of this the first time- Guess I should have spent more time investigating and set up proper lighting. Anyway, these pictures should tell the story:


The crank key was broken when it came out, and more importantly, had worn thin! Until I took the key out, the rust had hidden the fact that the crank slot was significantly wider than the protruding portion of the key.



The snout has unfortunately taken a beating. It is no longer smooth and round, and what I had originally thought were only rust patterns are actually low spots on the crank.



The areas of wear can be seen on the sprocket.

All this adds up to a loose fitting sprocket that can play enough to wobble, and may not be aligned when tightened down.

It appears that this thread describes another incidence of this problem. That user (mk75) apparently ended up purchasing a new long block. I would like to hope that mine is still salvageable. I have a new sprocket on the way and will get a key as well. Any ideas for filling the low spots and attempting to get a round crank out of all this? Part of me is tempted to fill the splines on the sprocket so that it will ride on the high spots left on the crank.

The "redneck option" of JB weld has crossed my mind, but even if I that stops it from moving, there's no guarantee it will end up properly aligned when tightened.

The woodruff key is what sets the sprockets timing and it should be a press fit holding it in place with the bolt torqued down. Looks to me that either the key was the wrong size or not seated when the sprocket was installed and torqued, keeping the sprocket from seating properly. I'd try the new OEM crank sprocket and woodruff key. I wouldn't file the crank or fill the sprocket with anything. Hopefully the sprocket seats on the crank like it should with the new key.