Hi all, I've been lurking and benefiting from the wealth of knowledge here for a few months, and I'm hoping you can help me out!

I recently picked up my first Montero, a 98 Gen 2.5 with winter package and 165,000 miles, in very good shape, WOO! Was enjoying the truck quite a lot, and quickly went ahead and did the timing belt, water pump, etc. The process seemed to go well, but afterward, I noticed the crank pulley was wobbling. Argh!! <img src="/forums/images/graemlins/angry.gif" alt="" /> However, I assumed it was possible that I'd been too rough on it or the rubber was going bad, so I pulled it off again and replaced with a new crank pulley. No improvement. Regretfully, I never looked at this before I tore into things, so it may have been doing this ever since I bought it. So, here are the details:

---------The wobble---------
-Appears RPM dependent, seemingly disappearing at higher RPM. Probably just a visual illusion, though.
-I initially thought it was temperature dependent... Oddly, the pulley seems much less wobbly when the engine is first started, then gets worse once it warms up. After further examination, I'd be willing to concede that it probably just seems this way due to the higher idle speed when the engine is cold.
-The alternator belt can be observed "dancing" slightly on its idler pulley, but not much. It seems to be a fairly subtle wobble, but that's still unacceptable!

---------What (I think) I did right---------
-The crank bolt is the newest design, with a new washer.
-The bolt is torqued to the full 135 ft*lb, I spent the time making a proper tool to ensure it was tight.
-The crank pulley is now brand new, lined up properly on the roll pin in the sprocket.
-The crank position blade and spacer are pressed firmly onto the t-belt sprocket, with the two small pins in place.
-Once fully torqued, the crank pulley is not loose, and can't be moved. It definitely seems to be tight.

---------What I'm suspicious of---------

1. The crank sprocket keyway looks undamaged, BUT appears larger than I would expect. The sprocket has nearly 1/2 tooth worth of rotational play on the crank when not torqued down. It fits rather loosely onto the crankshaft as well. Can anyone confirm if this is normal? The woodruff key itself is extremely tight in the crank keyway, so I didn't try to remove it.

2. The crank pulley was surprisingly easy to press onto the sprocket. It's a fairly loose fit until the bolt is torqued. When I first removed the original pulley, it was very tightly fused to the sprocket.

3. Could the replacement bolt+washer be slightly too long, bottoming out in the crank rather than applying the full torque to the pulley?

4. From what I've read, I gather it's fairly unlikely that the crank/bearings are actually bent/cracked/worn badly enough to cause this. Nonetheless, is there a reasonable method to check the snout runout?


.....

After the new balancer failed to fix it, I figured I might just drive the truck... but my gut just won't let me do that, just waiting for the bolt to snap and let that pulley loose. My next move would probably be to replace the crank sprocket, position blade, and spacer, unless there are better options.

Any input would be appreciated! I want to get this baby out on the trails... But I'd also like to make it back home.

Hello and welcome to the forum poolecr.

I just performed a complete overhaul of the 3.5L in my old 1997 over the past summer. I do not recall any kind of loose fitting crank sprocket at all. As far as I remember it was a really snug fit going over the woodruff key. So was the harmonic balancer.

I noticed you mentioned that the sprocket was something you would want to replace. I think you are on the right track. You are right about the crank bearings, the wouldn't wear enough to cause a visible wobble problem with the crank pulley. I mean, I suppose they could get worn pretty badly, but you would probably experience some severe engine performance problems before you would notice an engine wobble.

I'd start here. take the front pully (harmonic balancer) off, then by hand thread in the bolt and washer combo and make sure it can be screwed in flush to the end of the crank. Should spin in easily with your fingers all the way. Make sure the washer is installed in the correct direction too.

Woodruff key next maybe, but that is a lot of work being you have the timing belt on. Like starting that process over.

Might also consider a quick ID / OD check of the damper and the crank. Also, compare the new damper's ID to the old.

Since the damper aligns to the OD of the crank and the face of the timing belt cog, I would take a look at those surfaces as well.

Is it possible that your new pulley is machined out of spec?

All three of the above responses are from experienced drivers of these trucks. I'd seriously take to heart what they are suggesting. Hopefully it's a relatively easy fix and you aren't going to have to go through a whole timing belt change again to find it.

In any case, I'd say your hunch to not drive it at this point is spot-on.

John B.

This just caught my eye and maybe its just terminology differences...

1. The crank sprocket keyway - do you mean the woodruff slot machined into the end of the crankshaft? or the lower timing belt sprocket? either way - the woodruff key should be tight in the crankshaft, the timing belt sprocket and the harmonic balancer.

I just did the timing belt on my '92 last month. although not the same engine as yours, the concept is the same. The lower timing belt gear is not loose rotationally on the end of the crankshaft, it is a nice slip fit (not press) and should not be loose. Very precision machined tight tolerances on these components.

I replaced my woodruff key also, for sure it is held in the crankshaft very tightly, not a press fit, but close. I very carefully tapped it out of the crankshaft with a tiny screwdriver and soft mallet. After cleaning the crankshaft slot very well I pushed the new woodruff key in with my thumb. Its tight. Maybe even gently tapped it home with the soft mallet - don't quite remember. The woodruff key is a common size part. Cost me about $0.80 for a 10 pack at a hardware store.

I'm still leaning towards the bolt thou. Unless the inside diameter of your harmonic balancer is really oversize as Kevin mentions.

About your crankshaft bolt, does it look like the pink one in this photo?

http://www.expeditionportal.com/forum/at...072&thumb=1

Thanks for the great suggestions so far! I knew I came to the right place.

--Jay- I appreciate the sanity check on the sprocket fit. Sounds like mine has somehow degraded... Since the damper/pulley only fits over the sprocket and not the crank itself, I can see how this could be the source of my trouble.

Engine seems quite happy otherwise, so as you say, I don't think the bearings are that far gone.

--plh- Yes, the bolt length will be my first check once I get back to the truck (out of town this week). As for the washer direction- It appears symmetrical except for a small chamfer on one side of the inner diameter. Matching the original installation, I oriented this chamfer outward, away from the block. Do you recall if this is correct?

Woodruff key would be worth replacing, it does appear to be seated slightly more deeply into the crank at the end nearer to the block. Any advice on getting it out? Seems pretty stuck. Also, anyone have any info on the part number for that key? Can't seem to find it at the online OEM suppliers.

--Kevin- Definitely will check and compare. It's possible the new damper is off, though since the old one behaved the same I am inclined to give it the benefit of the doubt. Also, since the crank snout does not extend beyond the face of the t-belt sprocket, the damper ID doesn't actually interface with it, only with the bolt. Seems like a strange design choice to me... Or do you think there is something abnormal about my particular truck (a.k.a previous owner did something horrible)?

--John- Thanks, hoping it's not too bad! Though having done the timing belt twice already, I've kinda just resigned myself to doing it again. At least I'm getting quick at it, haha.

small chamfer towards bolt head - so you are correct.

The woodruff key lines the pulleys up so they are in time. The force from the bolt pushes them farther onto the crank which is tapered. I would double check the order of the parts going on the crank in the FSM and what you have going onto the crank and make sure nothing is missing there. If the pulleys were not seating the crank would spin inside the pulleys and shear the woodruff key, the engine would quit because the cams would no longer turn. I've had first hand experience shearing a woodruff key on a CRF450 that I had. Couldn't figure out why it wouldn't run until I pulled the flywheel off the crank. You can download the ASA tool to look up parts for your montero on mitsubishilinks.com I believe. Thats if you want an OEM woodruff key. A dealer could probably get you the part number too.

[EDIT] Maybe try starting it up and check the engine side of your crank pulley for signs of wobbling with a flashlight. If you haven't already. Could be less things to play tricks on your eyes that way. [/EDIT]

I have ASA and couldn't find the woodruff key part number. So I bought a pack of several, did a hardness check and micrometer check (not caliper) and the all measurements were the same 40HRc, 5mm x 9mm x 21mm (3.0l). I was working on a Saturday/Sunday so the dealer wasn't an option.

I would certainly prefer OEM parts.