Faulty timing belt??

[Paulm4]

Hi all, me mechanic friend and i are changing the timing belt tomorrow in my 01 Impreza WRX wagon. Tonight i stripped out the radiator, aux belts and 2 of the belt covers. Tomorrow my mate is coming over and we'll change the belt and tensioners.
As i was checking i had all the bits i needed i took the new belt out of it's box and had a good look at it. On one of the ribs there is what seems to be like fishing line flush with the surface of the rubber that is not visible on any of the other ribs.
See (not very good, taken on mobile phone) picture.
Should i use the belt knowing it's prob fine or have to go to the hassle of getting another belt and paying extra for it over the counter and then have to return my internet "faulty" belt.
Any advice?

Oh, new belt is a decent make, not some cheap crap!

[Paulm4]

Anybody got any suggestions?

[Riknos]

Erm, have I missed something, or is that not just a mark on the belt to help you to replace it without messing up the timing?

[FoundOnRoadside]

Riknos said:

Erm, have I missed something, or is that not just a mark on the belt to help you to replace it without messing up the timing?

This.

I think you need a different "mechanic mate", OP.

[CaptainSlow]

Another stupid question but why do you need a mark on the belt?

[FoundOnRoadside]

doogz said:

Bit harsh, his mechanic mate hasn't seen it yet.

Yep, my apologies OP. Posting before third cup of morning coffee = bad.

[Krikkit]

CaptainSlow said:

Another stupid question but why do you need a mark on the belt?

For long/complex belt changes it helps align them all so you know you haven't skipped a tooth.

An Impreza is a perfect example:

[TameRacingDriver]

CaptainSlow said:

Another stupid question but why do you need a mark on the belt?

So you fit it correctly and don't mess up the timing would be my guess (I'm not a mechanic though so could be wrong).

[AdeTuono]

TameRacingDriver said:

CaptainSlow said:

Another stupid question but why do you need a mark on the belt?

So you fit it correctly and don't mess up the timing would be my guess (I'm not a mechanic though so could be wrong).

But the belt doesn't need to align to anything. All the pulleys/sprockets need to be indexed, but it wouldn't matter which rib of the belt goes where, unless they're spaced differently around the length of the belt, which just wouldn't happen.

[Mr GrimNasty]

It's probably something to do with the manufacturing process and the point where it is joined/spliced.

[Mr2Mike]

AdeTuono said:

But the belt doesn't need to align to anything. All the pulleys/sprockets need to be indexed, but it wouldn't matter which rib of the belt goes where, unless they're spaced differently around the length of the belt, which just wouldn't happen.

Lots of timing belts have marks on them. When you have two cam pulleys they can be used to ensure that one is timed correctly relative to the other. You don't usually need them to time an engine correctly, but they can be convenient.

I'd have thought the OP's belt should have more than one mark though; a single timing mark by itself is no use at all and it's even less use if it's printed on the tooth side where you won't be able to see it once it's on a pulley.

[monthefish]

AdeTuono said:

TameRacingDriver said:

CaptainSlow said:

Another stupid question but why do you need a mark on the belt?

So you fit it correctly and don't mess up the timing would be my guess (I'm not a mechanic though so could be wrong).

But the belt doesn't need to align to anything. All the pulleys/sprockets need to be indexed, but it wouldn't matter which rib of the belt goes where, unless they're spaced differently around the length of the belt, which just wouldn't happen.

Exactly.

And fair play to the OP for having a go. I don't think I'd be DIY'ing a timing belt.

[CaptainSlow]

monthefish said:

AdeTuono said:

TameRacingDriver said:

CaptainSlow said:

Another stupid question but why do you need a mark on the belt?

So you fit it correctly and don't mess up the timing would be my guess (I'm not a mechanic though so could be wrong).

But the belt doesn't need to align to anything. All the pulleys/sprockets need to be indexed, but it wouldn't matter which rib of the belt goes where, unless they're spaced differently around the length of the belt, which just wouldn't happen.

Exactly.

And fair play to the OP for having a go. I don't think I'd be DIY'ing a timing belt.

Yeah, I don't think it is a reference mark maybe part of the manufacture of the belt as previously mentioned.

[Paulm4]

It's definitely not a reference mark. There are several already on the outside of the belt that line up with marks on the pulleys. It's basically fishing line but flush with the surface of the rib. Have seen plenty timing belts but never seen this on any of them. Have changed belts before so not a complete numpty but thought I'd get my mate to do this as I've never had a flat 4 car before.
Advising me to get a new mechanic, think that's a bit harsh, he's not even seen the car yet. Can't sack him either as he works for pizza!
Think I'll just fit it, thanks for the suggestions

Edited by Paulm4 on Friday 22 June 12:32

[230TE]

Krikkit said:

For long/complex belt changes it helps align them all so you know you haven't skipped a tooth.

An Impreza is a perfect example:

I'm trying to work up the enthusiasm to change the belt on our Impreza dogwagon. That picture just scared me.

[Krikkit]

Paulm4 said:

It's definitely not a reference mark. There are several already on the outside of the belt that line up with marks on the pulleys. It's basically fishing line but flush with the surface of the rib. Have seen plenty timing belts but never seen this on any of them. Have changed belts before so not a complete numpty but thought I'd get my mate to do this as I've never had a flat 4 car before.
Advising me to get a new mechanic, think that's a bit harsh, he's not even seen the car yet. Can't sack him either as he works for pizza!
Think I'll just fit it, thanks for the suggestions

Edited by Paulm4 on Friday 22 June 12:32

Just a bit of errant kevlar that is weaved into the rest of the belt then. Don't worry about it.

I'd like a bash at a timing belt on an Impreza, looks fun!

[Paulm4]

It looks complicated but it's not a bad job by all accounts. When the radiator is removed the access to the whole front of the engine is unrestricted. Certainly an easier job than my Fiat Coupe, that scared me so much I paid specialists to do it.
Updates tomorrow on how it really goes!

[S0 What]

Not seen that before i'd be taking it back and checking if they are all like it, never fook around with timing belts, costs are huge when they go snap !
Any timing mark would be on the outside, where it could be seen when fitted, pretty pintless having it hidden i would have thought ?
I allways mark the old belt with tippex on every toothed pully that counts IE crank, cam, diesel pump and or balence shafts then transfer those to the new belt a fit with the marks still aligned.

[rossmc88]

Speaking from experience of changing an Impreza belt myself, the marks on the belt are a godsend

The top right cam pulley is on cam when you line the marks up and likes to spin round

[Mr2Mike]

Paulm4 said:

Certainly an easier job than my Fiat Coupe, that scared me so much I paid specialists to do it.

I did the belt on my Coupe 20VT, it was very tight so not ideal for someone with plates of meat for hands like myself, but not that bad. The three timing belts on my ZS180 were much worse.