View Full Version : Steel Idler Pulley install ?

Michael Mattix
04-22-2004, 11:02 AM
I am replacing numerous things on my SC that are overdue which a blown radiator really bumped my plans on doing all this much sooner, but my question is this:

Is there anything special that you have to do when installing the steel idler pullies from Supercoupeperformance.com? My supercharger idler pully was smaller than the new steel one and I couldn't get the belt on because it was already SUPER tight. So, I had to put the original back on. But, the other ones won't move when torqued properly. I KNOW that can't be good. I haven't finished with my radiator install, so I haven't started the car yet and I'm worried about the other idler pullies not being able to move. There was a washer that came off of the old ones and I put them back on with the steel ones, but maybe I need to leave them off? Anyone know? Thanks in advance,


04-22-2004, 11:40 AM
Ya need to pay attention to what you are doing when you do that kind of stuff. The devil is in the details. ;)

The Stock SC pulley's use a dust shield to protect the bearing. Most new pulley's have an integrated seal on the bearing that removes the need of the stock dust shields. Some designs are such that if you install the dust shield on the new pulley, it will touch both the inner and outer part of the bearing, effectively stopping the pulley from turning.

I don't know what the pulley's from SCP look like, but if you installed the dust shields with them, try removing them. If you want to retain the dust sheilds (like the look) you can go to your local hardware store with your pulley and bolt in hand and find a washer to space out the dust shield a bit. I found a 7/16" stainless steel washer worked o.k. on mine. It depends on the hardware store and the pulley.

As far as the SC pulley. The new steel ones are all the same size. The stock SC idler pulley is slightly smaller than the other two. With the stock SC belt, a slightly larger pulley should work just fine. You may have a slightly shorter belt on your SC which makes the larger pulley not fit. You can keep the old pulley on there, or get a longer belt to work with the larger pulley.

Michael Mattix
04-22-2004, 12:51 PM
Man, Mike, your information was EXACTLY what I was looking for. THANKS! For future information, where am I supposed to "pay attention to the details" (as you mentioned) other than this site for anything other project that I want to tackle myself? No instructions came from SCP about these pullies, the Ford Service Manual didn't have any notes about checking to make sure that the pullies turn when torqued, and the search feature on this site didn't turn up much. If I would have left them, I wonder what would have happened? Nothing good, probably. I would figure these being such a cheap reliable replacement for the plastic ones that I have heard go out at about 100k, that there would be a lot of posts or a FAQ about this issue. I am glad I brought it up, but maybe this is a more of an obvious thing than I am able to figure out (not that experienced with cars). When I ordered my belts from SCP, I told him that I did not have a 5 or 10% pulley. I don't know if he gave me the stock belt or not, but I will call back and ask. I did call Bill yesterday to ask him if maybe I got the wrong idler pulley for the supercharger since the stock one is smaller, but he just said the larger idler pulley shouldn't make a difference. I REALLY don't agree with that! Thanks again Mike. Keep up the good free advice!

04-22-2004, 03:06 PM
You might want to call Bill at SCP and mention your issues to him. I picked up some Steel pulley's from a store once and inside the box was a tag that explained that the dust shield was no longer necessary. Maybe SCP ones also "used" to come with them.

If not, he should probably add some documentation for you.

I just tried the search and found it tough to track down as well. It's finding the right terms. "Idler pulley" hit pretty good with the number 4 solution titled "Super charger belt tensioner pulley" had the same answers that I gave you in it.

The Larger pulley should work just fine on the SC belt. It really should. But since you have a brand new belt it may be a tight fit.

You could run the car for a week with the smaller pulley, then put the new one on, once the belt has stretched a bit. Or you cuold use some soapy water to make it easier to slip the belt over it. Having a second pair of hands help you by holding the tensioner back is a big plus.

Good luck.