[Y2koutback]

Trying to finish up my first ever timing belt job, as I am fairly new to DIY maintenance it has been quite a learning expereince. As I was getting ready to install the new belt today, I decided to give it a once over, and I noticed two points of possible fraying!?

Its a brand new timing belt that was part of a complete AISIN kit. I didn’t see anything like this on the old gates belt I took off, should I be concerned? Should I install this belt or try to return it for a new one? Thanks for your suggestions.

 

[traildogck]

I have not seen that. It looks like the cordage reinforcement is not bedded into the rubber.

Return that. I would not be confident. Other can chime in if I am incorrect.

 

[Y2koutback]

Thats what I was afraid of. And I thought I was so close to finishing this up. I’ll have to get to work on the return process.

 

[traildogck]

Thats what I was afraid of. And I thought I was so close to finishing this up. I’ll have to get to work on the return process.

How can you trust it. I have a hobby business. I make urethane parts for Subarus. If that was my part, it would fail my QA/QC. Even if it IS viable. It looks bad. It fails the eyeball test. I have been in design and construction for over 25 years. If it fails the eyeball test ... How can you trust it.

 

[idosubaru]

While I agree - are we sure that's not just the juncture point where two halves of the timing belt come together, I dont' have one in front of me but they all have one "seam" of some type don't they?

 

[johnre]

Here's an easy thought experiment to give you your answer: Would you drive on tires that had such a visible defect in them?

I thought not.

While I agree - are we sure that's not just the juncture point where two halves of the timing belt come together, I dont' have one in front of me but they all have one "seam" of some type don't they?

There is no such "seam". These belts have to be constructed with many overlapping layers of reinforcing cord and rubber, not just one. Just like tires.

 

[Y2koutback]

Yeah I originally thought maybe it was a seam as well. But theres two points on the belt like that, and the old one I took off had nothin of the sort. Thanks for the suggestions, I’m starting the return process now.

 

[idosubaru]

There is no such "seam". These belts have to be constructed with many overlapping layers of reinforcing cord and rubber, not just one. Just like tires.

These markings are odd and I'm surprised others aren't commenting because these markings are not uncommon, i've seen them plenty of times though I don't know what this means.

Here are multiple people saying they have two of the same markings on each of their timing belts - exactly as the OP here states. @cardoc also says the stitching is normal:

https://www.subaruoutback.org/forums/66-problems-maintenance/59121-defective-timing-belt-part.html

 

[Y2koutback]

Interesting looking at that older post. So maybe the stitching marks are normal? I certainly dont want to risk putting a bad belt on, but I’m also having a **** of a time trying to return this one since it was part of a kit, and apparently AISIN doesn’t sell just the belt? I’m certainly not interested in un-installing the other parts and returning the whole kit. I’m at a complete stand still though until I get this belt figured out.

 

[traildogck]

I have just never seen it before. I have only installed Gates Race belts and OEM belts, and I never noticed anything like it before.

So pardon my alarm, I am sure there are others who have changed more belts than me.

 

[Y2koutback]

The belt I took off was a gates and I didn’t see anything like that either. Poking around the internet a little more seems like there are a few other people who have bout AISIN kits for various other cars and seen similar seems as well.

 

[joe_pinehill]

did you buy a kit and the belt in the Aisin kit is a Mitsuboshi?

 

[tumbleweed 49]

I wouldn't use it. It might be where the two ends join but why two places? Timing belt is too important to take a chance on.

 

[Y2koutback]

Yes I bought a complete AISIN kit from rockauto, and the timing belt is a Mitsuboshi. I showed it to the staff at my local parts store, they were about 50/50 on if it was a normal seam or a bad belt. But I agree tumbleweed 49, why would there be a seam in two places? And it is too important to take a risk on, I would not sleep at night. I’ve started the return process with rockauto, since I already installed the other components, I had to order the entire kit again, they said I could just put the bad belt in the new kit and return the whole thing. It will be interesting to see if the belt with the new kit has the same thing or not.

 

[joe_pinehill]

Yes I bought a complete AISIN kit from rockauto, and the timing belt is a Mitsuboshi. I showed it to the staff at my local parts store, they were about 50/50 on if it was a normal seam or a bad belt. But I agree tumbleweed 49, why would there be a seam in two places? And it is too important to take a risk on, I would not sleep at night. I’ve started the return process with rockauto, since I already installed the other components, I had to order the entire kit again, they said I could just put the bad belt in the new kit and return the whole thing. It will be interesting to see if the belt with the new kit has the same thing or not.

I did the timing belt in April and still have the belt. It was a Mitsuboshi. No sign of the defect you show in the photo. I would replace it. Your back up is a Gate or Continental belt.

 

[aesthetic.rake]

Here are two OEM Subaru belts I pulled off cars that got their first TBs at ~100k miles.

 

[Y2koutback]

Interesting. So maybe mine wasn’t defective after all. It’s weird that it’s not common across the board to have seams like that.

 

[joe_pinehill]

and By the way, good find, 3 out of 5 of us would probably have just unpackaged and installed the belt.

 

[Y2koutback]

I was just about to install it, maybe something from my climbing days kicked in and said to do a quick inspection first. Who knows though, good chance I would have installed it and all would be fine and I’d never know.

 

[cardoc]

The stitching is normal and necessary in constructing the belt.

http://www.sdp-si.com/PDFS/Technical-Section-Timing.pdf

https://ww2.gates.com/europe/brochure.cfm?brochure=12908&location_id=19798

the math: https://onlinelibrary.wiley.com/doi/pdf/10.1002/pamm.200701115