R53 new serpentine belt doesn't fit after pulley mods
 

Good day all... Requesting some assistance from the forum.

While doing my timing chain, I also upgraded / replaced some accessory pulleys. I upgraded to way motor works 15% reduction supercharger pulley, PWR fluid filled harmonic balancer crank pulley, a belt tensioner, and a replacement idler pulley. In all, 4 of the six pulleys were replaced.
I also purchased a gates shorter belt (1379mm) that my forum research has shown would fit well and is shorter than stock. However, I can't get it to fit around the idler pulley. I ended up getting a 1385mm belt (used on JCW variant mini cooper S) and it doesn't fit either.

Has anyone experienced this issue? I believe I am doing something wrong, but can't seem to find it. I've replaced a belt on this car before and filled a video from ModMini for supercharger pulley install, but still can't figure out what I am doing wrong.

Any assistance would be greatly appreciated. Thank you!

Is the idler pulley in the correct mounting hole? There are two holes right next to each other with the same thread size and apparently conflicting info in pictures, videos, and owners observations on which hole the pulley should be mounted.

This thread might help, but it also doesn’t seem to provide definitive proof on which hole is correct:
https://www.northamericanmotoring.co...er-pulley.html

OMG... Yes, indeed
 

I am speechless... That was absolutely the problem. I had put the idler pulley in the lower (left of the two M8 holes in question). By switching the pulley to the upper (right) position, the 1379mm belt slipped right on.

Thank you!
​​​​

Great! Good to hear it was a quick and simple fix... another point for the upper hole.

Did you have the other bolt and if you did, was the recess in the cover what threw you off? One poster in the thread only used the pulley and said his timing cover wasn’t leaking.

Also, you didn’t mention a pulley kit or spark plugs. Did you change them to the colder plugs required with the SC pulley?

I believe it wasn't there initially. I pulled the car apart months ago and thought I lost it. I purchased the torx M8 bolt from outmotoring and placed it (apparently) in the wrong hole. Now I'm not so sure it was misplaced, as it was the only bolt to go missing.

I did get a set of colder plugs, but not in a kit as they were cheaper to purchase separately.

I've lost track of all the projects I tackled during this venture. Timing chain and related components, crank pulley gasket, stuck oil filter housing, new pulleys as stated above, stainless steel valve cover bolts, spark plugs, new oil-less air filter, pcv line repair, all LED front lights / fog lights, union jack tail lights, sprint booster, auto up/down window circuit...

And I still don't know if the darn thing will run when I'm done.

​​​​​​Thanks again for helping me over this hurdle.

​​​​