Advice Requested - Timing Belt Job

[dmppdx]

Hello everyone. First of all, thanks to everyone for all the great information on this website, particular to Timmy the toolman and Sean.

I have been working on a timing belt job for my 4runner and run across an issue I was wondering of others could provide input on. I got to the point of the timing job where I pulled off the harmonic balancer and noticed that it appeared to have some epoxy or something similar between the harmonic balancer and the crank shaft. It didn't make any sense to me until I noticed the crankshaft where it harmonic balancer slides on was a little rough and had a few groves in it. The harmonic balance shows no wear on the inside, but it also has a number on it from a paint pen that makes me think it was from a junk yard and had been replaced.

My guess is at some point the bolt holding the harmonic balancer on came loose and allowed the harmonic balancer to slide off the key enough that is started to spin on the crankshaft. Since the spinning harmonic balancer caused some wear on the crankshaft, to take up the extra space between the crank shaft and new harmonic balancer, they put some epoxy on it to keep the harmonic balancer tight on the crankshaft and to keep it from moving laterally on the crankshaft. That is my guess at least since that is the only thing that seems to makes sense, but maybe there is some other explanation.

So my question is, at this point, what should I do about it? I was thinking it makes sense to use some epoxy again on it when I reinstall it so the harmonic balancer doesn't move around since that might result in the bolt not holding or adding more vibration to the engine. If so, should I just use normal epoxy? I was thinking of pulling a tiny bit of oil on the crankshaft and then putting the epoxy in the hole of the harmonic balancer before sliding it on that way the oil will prevent it from sticking that well to the crankshaft and allow it to be removed if needed.

I noticed when I removed the balancer, I had to use a puller and it didn't come off very easily, which I assume was the result of the epoxy or glue that was currently on there, but I have no idea what type of glue or epoxy it was. I would think it would want to us a low of strength as possible to allow for to come of easy, but I'm not sure if this is correct of what specific epoxy or epoxy that would be.

Does anyone else have any thoughts or suggestions on this?

Attached is a picture of the crankshaft showing the epoxy that is black that was on it.

 

[dmppdx]

Here is the picture of the crankshaft end.

 

[Outrider]

I can't really tell from the picture, but it is common to use JB Weld to repair things like that. I know that I have successfully used it twice to fix nicks and gouges on camshafts under the seals, that were causing leaks. JB Weld is a type of epoxy with metal powder (or something like that) in it. It can be used to build up metal, fill holes, etc., then machined. I know that if my HB came off and buggered up the crankshaft, that would be what I used in my first attempt to repair it.

JB Weld really can't "glue" broken crankcases or tractor blades back together, as the label might lead you to believe, but it is really handy stuff, when used properly. Meaning, it needs to be taking compression loads, and not tension loads. It is a strong filler. It cures hard, and can be machined, drilled, tapped, etc. Not nearly as strong as solid metal, but often quite better than nothing, and sometimes the only option, in certain cases.

In the case of a damaged crankshaft, I would goop it on, oversized, let it cure (24 hours minimum), and then attempt to machine it back down to the original intended size, with a file, sandpaper, etc. I did something like that on my nicked camshafts, and it worked like a dream, stopping the oil leaks.

Just something for you to think about, as you wait for more replies, likely from people who have ran across this situation before.

If your situation is what I imagine, JB Weld wouldn't be used to glue the HB back on, but rather to provide a better surface for it to mate to the crankshaft. The bolt would still be doing all of the work keeping the HB on the shaft.

 

[thegipper]

Post some more/better pictures of the damage to the crank. How thick was this epoxy on the crank? If its paper thin, its most likely not really doing anything.

If the damage was minor to the crank and there isn't any damage to the HB, you'll probably be fine with just properly torquing the bolt to spec.

 

[dmppdx]

Thanks for the responses. Below are two more pictures.

One shows in more detail the crankshaft and the damage to it and the amount of material on it. It seems to be about 1/2mm thick, but that is just a guess.

The other picture is the harmonic balancer and how what ever it was kind of pooled up a little at the end of the hole since there is about a 1/4" space between where the hole ends and the crankshaft ends so there is a space for it to accumulate there. There was more of the material initially on the harmonic balance but it cracked and fell of.

 

[mtbtim]

I'm guessing a previous timing belt job was botched when they didn't properly tighten the crank bolt. The bolt came loose and the harmonic balancer spun on the end of the crankshaft causing some damage. That's what it looks like to me since you can see a groove ground into the shaft.

 

[sportscarfan]

Shouldn't there be A LOT more crank key than that little bit sticking out from the timing belt gear?

 

[weekendclimber]

Shouldn't there be A LOT more crank key than that little bit sticking out from the timing belt gear?

I believe so. Here's a shot with the timing gear off showing the entire crankshaft. If you blow it up to full size (click the yellow bar above the picture) you can see the grove where the woodruff key comes out of the timing gear and would then engage the HB. Looks like a good half inch or more at least should engage the HB.

 

[dmppdx]

I'm guessing a previous timing belt job was botched when they didn't properly tighten the crank bolt. The bolt came loose and the harmonic balancer spun on the end of the crankshaft causing some damage. That's what it looks like to me since you can see a groove ground into the shaft.

I believe that would be correct. When I took the bolt off, it was on crazy tight. I had to us a 3 feet cheater bar on the breaker bar and had to put as much force as I was able to do using both arms to get it loose, so my guess is when they put it back on, they cranked it down a tight as possible to keep it from happening again.

 

[dmppdx]

Shouldn't there be A LOT more crank key than that little bit sticking out from the timing belt gear?

The key seems to be slightly damaged on the end on the corner and I'm guessing that from when the HB started to slip outward and at the very end of the key got damaged right as the HB slipped off it and started to spin.

In terms of length, I believe it is all there. From Tim's video, there isn't a whole lot sticking out past that belt gear and the larger washer next to it. I believe the key sits in a channel and the key is flush with the end of the channel, so it appears it is all there length wise. I'm not too concerned with the key holding the HB in place, I'm more concerned with any slop on the HB being on the shaft and what impact that would have on the bolt staying tight or vibration it might cause.

Thanks for everyone input so far.

Now I need to figure out how to get that washer and the belt gear off since it appears the glue is holding them on and I'm not sure there is a great way to use a puller on that washer.

 

[weekendclimber]

The key seems to be slightly damaged on the end on the corner and I'm guessing that from when the HB started to slip outward and at the very end of the key got damaged right as the HB slipped off it and started to spin.

In terms of length, I believe it is all there. From Tim's video, there isn't a whole lot sticking out past that belt gear and the larger washer next to it. I believe the key sits in a channel and the key is flush with the end of the channel, so it appears it is all there length wise. I'm not too concerned with the key holding the HB in place, I'm more concerned with any slop on the HB being on the shaft and what impact that would have on the bolt staying tight or vibration it might cause.

Thanks for everyone input so far.

Now I need to figure out how to get that washer and the belt gear off since it appears the glue is holding them on and I'm not sure there is a great way to use a puller on that washer.

Unless you need to replace the seal behind the timing gear (which honestly, I would since you're this deep into the job) you wouldn't need to remove that. I understand if you'd want to though. I'd hate to think you'd have to cut that thing off

 

[dmppdx]

Unless you need to replace the seal behind the timing gear (which honestly, I would since you're this deep into the job) you wouldn't need to remove that. I understand if you'd want to though. I'd hate to think you'd have to cut that thing off

I would really like to replace the seal since it appears to be leaking a fair amount. I don't really want to have to cut off the washer, so I guess I will see if I can get it off without cutting it off. If not, I guess I can live with the leak.

 

[mtbtim]

I would really like to replace the seal since it appears to be leaking a fair amount. I don't really want to have to cut off the washer, so I guess I will see if I can get it off without cutting it off. If not, I guess I can live with the leak.

I bet you could pry that washer off with some regular old brute force. Tap on it from various sides with a plastic mallet or grab ahold of it with a channel locks with a rag between the jaws and the washer and pull and push to break the bond of whatever goop they used. You could also try a little heat from a butane torch.

In our video for this job, we used a puller to get the harmonic balancer off. You can do the same for the crankshaft timing gear. The following is info we provide in the video description of Part 1:

*(2) M6 Metric Bolts with a 1.0 Pitch, 100mm long with 4 washers - these are the bolts you would use in conjunction with the OTC 4518 puller or other puller you have if you found the crankshaft timing gear was stuck onto the crankshaft.

Good luck!

 

[gamefreakgc]

It would be worth your time to also remove the woodruff key and replace it. That old one on there is rounded and should be square. Although it does look to also be glued in place.

 

[TheDurk]

It would be worth your time to also remove the woodruff key and replace it. That old one on there is rounded and should be square. Although it does look to also be glued in place.

It doesn't really do anything once the bolt is tightened. It's just there to keep things aligned while the bolt is torqued down. If the bolt gets loose, the key just shears.

I wouldn't bother as long as there is no rotational play in the timing gear.

 

[gamefreakgc]

It doesn't really do anything once the bolt is tightened. It's just there to keep things aligned while the bolt is torqued down. If the bolt gets loose, the key just shears.

I wouldn't bother as long as there is no rotational play in the timing gear.

It depends how tight the key fits in the crankshaft. I agree, if there's no play in timing gear then it should be ok but if there is play it will allow the crank pulley to eat up that key even more and make matters worse.

 

[Wedgy]

If you use JB Weld, Devcon, Marinetex, etc. a great release agent is shoe polish or car wax like Turtle Wax, we use it for bedding gun actions.

 

[TheDurk]

It depends how tight the key fits in the crankshaft. I agree, if there's no play in timing gear then it should be ok but if there is play it will allow the crank pulley to eat up that key even more and make matters worse.

No, it won't. The crank pulley and timing gear are held firmly in place by 217 ft-lbs of torque on the bolt. If the crank pulley or gear are able to move at all, meaning that bolt has come loose, that key will make no difference at all. It will just shear in a microsecond. The rotational stress on that pulley is enormous and the key is soft. The reason you don't want play in the timing gear is to maintain the precision of the alignment of the timing components WHILE the bolt is tightened. It doesn't matter after that.

 

[6uam671_T4R]

I’m looking at your pic and it appears the plate between the balancer and timing gear is backwards. The concave side is supposed to be towards the balancer. My guess is that has something to do with the previous installer over tightening the balancer.

 

[SaulG]

Belt Guide

I6 5m motors did this alot, sharpen a good putty knife and scrape the goo off.
Remove crank pulley, change key if you wanna.
Pic filler material, clean crank, install key and toothed pulley
Apply filler . .slowly remove toothed pulley and clean immediatley of filler
machine/sand/file as needed "Wedgy" it and reinstall using known good balancer.
Torque