I saved this a long time ago from some website, dont remember which. maybe it will help some:

 

Looks more like his tensioner is totally shot.

 

Yes it's a handy chart, but these charts always neglect to provide numbers for the M7 16% pulley which was the original point of my thread.

 

It may not be the gap. The pic looks like the belt is off by 1 groove. Is the pulley positioned as close to the SC nose as it should be?

 

^^^ yup, and i personally checked this while the install was being done. but i'm guessing the pulley is misaligned

 

I would second the tensioner funk - totally possible for causing the belt to hop.

 

I checked on my tensioner... but can't see any hole. Is that a sign that I need to change the tensioner?

 

i purchased a Goodyear Gatorback #4060537 for my M7 16% set-up. It was worked perfectly so far.

 

Edit

 

You should see at least as much as is in the image.

If not, it's way past change time.

 

Then it's waaaaay past change time! I'll get down to it asap.

 

So has anyone changed the NAPA belt that Octaneguy specified? Hornguys? Any impressions so far?

TIA!

 

Well I finally got my M7 16% SC pulley on. I also picked up the NAPA 25-060535 belt for it, but it would not fit, NO WAY!. Now maybe there are variations like Drewmon says, so I'm gonna take it back and compare. I'm probably going to exchange it for the 060539 though. This is with an OEM crank pulley. The chart posted calls for the 060539 for both the 15% and the 17%, so it should be good for mine.

 

I put a 535 belt on my M7 16% equiped car last week. It was a very tight fit but it finally went on and everything looks & works fine...

 

I compared my 060535 to another one at NAPA and mine was a little shorter. It probably wasn't enough for me to install it though, so I got 539. It went on without any problems, and I can see the entire index hole.

 

The problem with that chart is that people are using smaller belts now. The belt that chart says is a good fit for a 19% pulley is what people are using on the 15%-17% pullies. So that must mean that it really isn't as good a fit on the 19% as it could be.

So, what belt for the 19% pulley, my car is in need of a tune-up and I figure I'll change the belt and buy a spare as well...

Also, how much are new belt tensioners from the local stealership? My car has about 54k miles, gonna check tom if I should be replacing it, but just in case...

 

So does anyone know the correct, or better, size for the 19% pulley with stock crank pulley?

Also, if you can't see an index hole then you should replace the tensioner correct. What exactly does being able to see the hole or not mean, like how does it affect the performance of the tensioner?

Thanks.

 

So if that chart could be off, what should I run with a 15+2? I'm currently running the stock belt w/ a 15%.

On a funny note, I have no hole showing as well

 

I've only looked at the Gates/NAPA belt sizes so if you use one of their's you'll probably have to stay with the stock size 060547. The next size down looks like the 060359 which I'm using on a -16%,+0 setup. The entire index hole is showing plus a little more. I think it would be too tight on your setup even if you could get it on. You could give it a try though, and take it back if it doesn't work out.

 

My guess would be the 539 belt but I have no clue...

Yeah it's not so funny replacement is $115ish plus labor if you don't do it yourself lol. Does it really need to be replaced?

 

The 060535 should work fine for a 19% pulley because it is smaller than the 060539. I believe the chart is accurate from my experience. I have a 17/% pulley and initially installed a 060535 belt. After 2,000 miles it shredded because it was just too tight. I have been using a 060539 the past 20,000 miles with no issues.

 

If you are interested in using Goodyear the #4060537 is a perfect fit for a 16%.

 

Ohh man, the Gatorbacks from Goodyear.. that's some good stuff. We had a Vortech 350Z that had a Reduced pulley, we'd change belts all the time cause either there was slipping or they'd just be too tight and start to fray. We changed it out with a Gatorback and voila... haven't had to change the belt since, and it's already been a good 6 months.

I just ordered the M7 16% today, and I'm going to be picking up #4060537 from Goodyear, as forementioned. I recommend going with the Gatorback belt... definitely.

 

PS

The 060539 belt has settled a bit and the tensioner index hole now looks like the one in Partman's pic.

 

ditto. i have the same and it is still going strong after 30K. i will replace it soon with the same.