How much does a timing belt stretch in its normal lifespan?

In the middle of a timing belt change. My old timing belt was in decent shape. It only had one rough spot on an edge that could've turned into a fray

When I held them up next to each other, I wish I would've done a better job but I could tell the old one was a bit stretched.

Then I had a bear of a time getting the new one on. And I had not put in the tensioner only the tensioner pulley per all instructions.


I guess the reason I ask is looking back that old was probably stretched more than I realized but at the same time, I'm also curious why I seemed to have more trouble getting the new one on than in all of the videos I watched.

I finally had to take the idler pulley off on the lower driver side Get the slack on that side and then put on the idler pulley back on.

If I tried to get the slack on the passenger side like they did in the videos, it would end up hopping a cog on the right side And I had no luck with putting a clamp on to hold it in place except for when I removed the idler pulley and used that method along with carefully rotating the crank and driver side cam to get the right amount of tension

This got me thinking, although the tensioner takes up slack with a stretched belt it has to throw the valve timing off because the tensioner is only on one side and that means the valves, at least on the driver side, have to be late opening and closing

 

One trick that I see a lot of people miss when doing a timing belt job is that instead of rotating the engine so that it’s at TDC, rotate the engine past TDC about 15° so that the cams line up with the “T” mark instead of the TDC mark. This puts the cams in a spot where they won’t move or shift.

Not sure if you used that method or not but I did and I found it super easy to get my belt on.

 

In simpler terms. Put on "T" mark not thw "TDC dot" mark

my belt slipped on pretty easy. Just had to make sure the teeth were lined up and *pop* on she went.

 

I saw that same tip and yes, I did. I ended up having to play with each one (each cam and the crankshaft) individually when I was getting my timing belt on. It would've never worked for me like I saw in the videos. It was just way too tight.

Using clamps to keep the timing belt from jumping cog on the camshaft pulleys and taking off the idler pulley

then it was a breeze

i'm jealous. I had to battle mine, but once I saw that tip about taking off the idler pulley and using clamps so the timing belt would quit jumping cogs on the cam shafts it was easy as could be