2G WTF Timing belt shift

[GSXRunner]

Anyone have this happen to them before? You know how the timing belt is aligned with the outside edge of the cam sprocket and part of the teeth show after the inside edge? Well, when I started it up, the belt shifted so that it is now aligned with the inside edge and the teeth show on the outside edge. It started cutting a groove in the side of the timing belt from the pizza cutter edge of the tensioner pulley that it was riding on. The timing is still correct; it didn't jump any teeth and it is tight. I took it apart and figured maybe I just got careless and overlooked that the belt was riding on the pizza cutter, so I redid everything making sure the belt correctly installed. I just put everything back together, started it up and the belt moved back in that position. Now it could be that since there's a small groove in the belt, it caught that grove caused it to move back in that position (which would mean, just a new timing belt is needed), or it could be something else. I know I'll figure it out eventually when I take it apart again, but if anyone has had this happen to them, I'd appreciate hearing what happened before I tear it down and re-time it. I'd hate to see this happen again with a brand new belt.

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[pauleyman]

Check the arm that the eccentric tensioner bolts to. The bushing is a known wear point. If the arm moves the tensioner isn't square to the belt.

 

[GSXRunner]

Has this ever happened to you? I will check that tomorrow when I tear it down. Anything else to look for?

 

[pauleyman]

Me personally no but I've seen it and it's been discussed.

 

[GSXRunner]

Me personally no but I've seen it and it's been discussed.

Do you have links to these discussions?

 

[pauleyman]

There is a search function.

https://www.dsmtuners.com/threads/why-is-my-timing-belt-riding-like-this.535209/post-153811891

https://www.dsmtuners.com/threads/timing-belt-wander-fix.530506/post-153775313

 

[GSXRunner]

Okay, so I think I found the problem. It's not the pivot arm or the bushing; those are in great shape.

The engine mount bracket (which holds the spindle that the arm pivots on) wasn't torqued down. The three bolts on the bottom were finger tight. That would definitely cause the tensioner pulley to be unstable causing the problem. It's not like me to forget to torque bolts, but I imagine I must have tightened them finger tight and in the process of looking up the torque specs, I got distracted (phone call, wife calling me for dinner, door bell, etc.) and when I got back, assumed they were already torqued. I'm going to make it a rule of thumb to never walk away from bolts that haven't been torqued down under any circumstances.

My new belt won't be here til Tuesday, so I cannot put everything back until then.

 

[GReddyTalon]

That's awesome that you are able to rip it apart and put it back together by yourself. I envy you for that.

 

[Mech Addict]

Is the current belt now tracking correctly with all torqued to spec, or did you replace it as a precaution? Just curious if it would get ruined from only minutes of run time. Nothing makes 4g63 owners wince like the words "timing belt".

 

[GSXRunner]

Is the current belt now tracking correctly with all torqued to spec, or did you replace it as a precaution? Just curious if it would get ruined from only minutes of run time. Nothing makes 4g63 owners wince like the words "timing belt".

I have the new belt on order; it arrives Tuesday. The belt I have is brand new but because of the pizza cutter edge of the tensioner pulley, there is a groove cut into the top of it and the edge is a little worn. It probably won't be a problem, but I don't want to take a chance with something as vulnerable as the timing belt.

That's awesome that you are able to rip it apart and put it back together by yourself. I envy you for that.

It's not a fun job, but it's not difficult either. Anyone can do it if they put their mind to it. Doing the actual work on the timing is quite easy. I think the most frustrating part is putting the A/C pulley bracket on; you have to be a contortionist to get the lower bolt in.

 

[AWD-Tony]

I'm a torque-nazi, especially under the timing cover.

 

[GSXRunner]

I'm a torque-nazi, especially under the timing cover.

Unless it's on an engine stand, some of those fasteners are impossible to reach with a torque wrench.

I didn't feel like waiting til Tuesday so I put the same timing belt back in. The groove is more of an indentation than an actual cut. Everything runs fine as I just got back taking it for a spin.

So remember, if your belt is doing a dance and your tensioner bushing/spindle seem fine, it may just be that you forgot to torque the engine support bracket bolts. Don't walk away from an un-torqued fastener that you just threaded in with your fingers; you may just forget when you get back like I did.

 

[pauleyman]

I didn't feel like waiting til Tuesday so I put the same timing belt back in. The groove is more of an indentation than an actual cut. Everything runs fine as I just got back taking it for a spin.

So remember, if your belt is doing a dance and your tensioner bushing/spindle seem fine, it may just be that you forgot to torque the engine support bracket bolts. Don't walk away from an un-torqued fastener that you just threaded in with your fingers; you may just forget when you get back like I did.

In light of a recent bolt mishap myself I have now gone to whiteout on every critical fastener I touch. If I mess with a bolt it gets whiteout after final torque. Quick glance tells me either I didn't do it or I forgot to whiteout. NEVER miss a fastener that way.

 

[AWD-Tony]

Unless it's on an engine stand, some of those fasteners are impossible to reach with a torque wrench.

I did a 2g timing belt a few months ago and I was able to torque every bolt. You’ll have to switch short/long socket for a few bolts.

I would recommend replacing it. You’ll hate yourself if it decides to let go.

 

[Mech Addict]

In light of a recent bolt mishap myself I have now gone to whiteout on every critical fastener I touch. If I mess with a bolt it gets whiteout after final torque. Quick glance tells me either I didn't do it or I forgot to whiteout. NEVER miss a fastener that way.

They did this at the factory on a number of fasteners, even the chassis, or I assume that is what the pink paint on bolt heads is from. Also, I have a rebuilt transmission from TRE, and every bolt has a dab of paint (and they used new fasteners).

 

[GSXRunner]

In light of a recent bolt mishap myself I have now gone to whiteout on every critical fastener I touch. If I mess with a bolt it gets whiteout after final torque. Quick glance tells me either I didn't do it or I forgot to whiteout. NEVER miss a fastener that way.

That's a good idea as long as you don't forget to remove the paint when you loosen them.

I did a 2g timing belt a few months ago and I was able to torque every bolt. You’ll have to switch short/long socket for a few bolts.

I would recommend replacing it. You’ll hate yourself if it decides to let go.

The only bolts I had too much difficulty with are the tensioner pulley and the three bolts that hold the support bracket to the block; the rest I torqued. I have 4 different torque wrenches. The tensioner pulley I could only reach with a beam style torque wrench from the top only. The problem is, I need to be on the bottom to hold tension while I tighten the bolt or the tension would loosen up. If I had a helper, I would have them hold tension while I tightened, but I always work solo. I've been turning wrenches for so many years that I trust tightening by feel when it becomes too difficult to use the torque wrench and have never experienced an issue as a result. The three bolts at the bottom of the engine bracket, because of its shape, can only be accessed under the car. You can't fit a long socket in there and a short socket will not reach. Now if you have a stubby extension (which I have, but can't seem to find it), you can use it with the short socket to reach it. Those I just torqued by feel.

As far as the timing belt, I literally put the belt under a high power microscope to see if there was any damage. The groove was just an indentation, there was no cracking or splitting in the belt. The edge of the belt which is normally square is slightly rounded on the outside edge, like a 0.5mm fillet; the toothed side is untouched. After running the engine, the indentation is almost gone due to the pressure of the idler and tensioner pulley. Regardless, I will recheck the belt from time to time to see if there is an issue that develops.

 

[pauleyman]

Yeah I'm gonna catch hell for this but I rarely actually get out the torque wrench. Even on timing belt stuff. I will torque stuff that's really low or really high and always torque wheel lugs.

 

[Mech Addict]

I agree that with experience you can develop a good feel for when a fastener has hit the sweet spot of proper clamping but not past the limits of the steel. I still get spooked when aluminum is involved. It seems to have a very different feel, even though is is usually just the threads in a bolt hole and not the actual bolt.