FAQ: Upgrading Serpentine Belts & Pulleys?

oldsman105 wrote:

I would change them.

AA wrote:

Also, I've been told that more than one deep crack per 1" of belt length means to change the belt.

ALSO

I started to change the belts last night and things didn't work as smoothly as I hoped. The way I tried didn't work and I ended up going the route everyone else used. In the process I found that I probably should change the lower pulley behind the engine mount. Is this the right part number 38007?

Nope, I posted them a few posts back. Dayco is 89006, Gates is 38001. www.daycoproducts.com has an excellent interchange function to use to find alternate mfgrs. I think the Dayco pulley I used is a better quality part than the Gates I have but did not use.

So you've removed the engine mount? Once you unbolt the bracket, 3 bolts, it takes a bit of maneuvering in order to get a torx bit on the pulley bolt. Not much room to sneak the bolt completely out and yank the pulley, but it will come out.

Hmm. That was the part number from Carquest. Maybe they rebrand the pulley with a different number or something. Anyway, I will go with your part number and hopefully get it all finished tonight.

I also just typed in your 38007 Gates part # in the Dayco interchange and it does not cross reference to what you need. Is the 38007 a plastic or steel pulley? 38001 and 89006 are steel. I have not seen 38007 referenced on any threads as one to use for a replacement anywhere.

Wow, they sure have a worthless website. (Carquest that is)

1998 Riv wrote:

I also just typed in your 38007 Gates part # in the Dayco interchange and it does not cross reference to what you need. Is the 38007 a plastic or steel pulley? 38001 and 89006 are steel. I have not seen 38007 referenced on any threads as one to use for a replacement anywhere.

I think it might be plastic. Metal would probably be better, but from what I have seen the bearing usually goes first. The stock pulley doesn't look bad, the bearing just makes a grinding noise when you spin the pulley. I will try to see if it fits tonight. It measures 3.5 inches and looks just like the stock pulley. I can get the parts for a little over cost, so that is why I was going that route. Some of the parts I have gotten in the past have been other brands and just thrown into a carquest package. Wish me luck.

A newer Gates plastic pulley should be a lot better quality than the crappy OEM pulleys from the factory. I chose to go steel after seeing how badly deformed the old plastic pulley's flat surface had become, probably after 118k miles. 3.5" is right, if it bolts in nice and tight, go for it. Make sure it isn't any wider than the old one, there's not much room to spare.

Pulley bearing grinding = bad news.

At least it doesn't look like this one http://www.bonnevilleclub.com/forum/viewtopic.php?t=43997&highlight=supercharger+idler+pulley.

Haha, yeah, they sure don't look like this!



I wasn't even sure what it was when I first saw it!

Travis (guy who took that pulley off his car) puts on about a billion miles a year. That pulley lasted around 250,000 miles. Sad part is he replaced the pulley one week and the water pump went the next week.

The pulley went in fine and the belts are changed. Took longer than expected, and hopefully I won't have to do it again soon. The lower idler pulley had a lot of dirt packed in it and you can hear something rattle when you shake it. The little instructions that I posted will not work on our cars. You have to support the engine and follow the directions that Jack gave.

Change all the idlers while you are at it. The belt change is a big hassle and if the pulleys fail you will have to do it over again.

I lost a pulley causing me to lose the SC belt. Six months later I lost another pulley and it took out both belts. Luckily I was less than a mile from home.

I changed the idler and tensioner pulleys a few days before. The tensioner pulleys and the lower supercharger idler pulley made a rattling sound when you shook them.

Did you replace the accessory tensioner pulley as well? I had a little squeaking a couple months ago and found the bearing was pretty bad on that one. Easy to replace anytime, check it out if you haven't yet.

1998 Riv wrote:

Did you replace the accessory tensioner pulley as well? I had a little squeaking a couple months ago and found the bearing was pretty bad on that one. Easy to replace anytime, check it out if you haven't yet.

Yeah I changed that to. It also made a rattling sound when you shook it.

i changed my belts and put the larger tensioner pulley on and when i star the car for the past 2 weeks the belt has a small cherping squeel noise. any idias why? it could be that the ne belt is 2 tight with the larger pully?

There are marks on the tensioner that indicate if it is operating within an acceptable range of movement. Someone here has posted a pic of that. I expect that if you can get the belt on, it is not too tight. It runs as tight as the tensioner makes it.

Is it possible it is not coming from the SC? Maybe the power steering pump? Checked the fluid level? Take the belts off the tensioners and check all the pulleys for looseness or a rough feel/sound when turning by hand.

the belt is making the noise. i no that much, and it was not happening b/f i changed them. its not the power steiring. where is it that shows the marks that show the operating range.?

The marks are actually cast into the body of the tensioner. I'll see if I can find the pic thread here.

Is that noise constant, or just at startup?

i think my my supercharger belt is slipping. i recently dropped 2 a 3.4mps and a 3inch shorty downpipe with a 3inch pipe in place of the cat.now 4 some reason it takes longer 2 build boost and im only hitting about 7psi max at the top of a shift it sits at about 5.5-6psi b4 that. i used 2 get 9.5psi somtimes 10 on a cold night max with my 3.5. the only thing is it dont squeak like u guys r explaining it when i let of the gas at wot. could it be slipping or did the downpipe just kill my boost that bad? maybe my boost gage is messed up? what u guys think?

Change the smooth 3" SC idler pulley to a 3.5". That allows you to keep the stock length belt and drop SC pulley, like you did.
The Dayco P/N for a 3.5" steel pulley is 89006. FYI, This one is right hand thread.

allright thanks! thats what i was thinking i"ll try 2 get 1 today

Josh,
Correction: The smooth tensioner pulley is "Left Hand Thread"
Pulley # 3, just above the idler pulley # 9, in the picture on page # 1 is the one you want to replace.
Sorry for any confusion.

turtleman wrote:

that's where the tensioner sits as it is now. Is that little notch i barely see the indicator?

Turtle,
Where did you get the larger diameter grooved idler pulley? (pulley # 8)
It looks a lot bigger than stock in the picture, maybe it isn't I can't tell for sure.
Anyway if it is larger, what make and p/n is it?
Thanks