ARGH!! I posted here before regarding my alternator belt. The blasted thing keeps rolling over and riding on the back side (read: flat side) of the belt on the outside edge of the alternator pull!!! One good snap of the throttle and that baby heads south!!! I've boiled the motor twice having this happen to me!! I've shimmed it, tightened it, coated it, beat it, bent it, reinforced it, screamed at it, and cryed over it!!! I have been calling around all morning (to the scrap yards) trying to find a serpentine belt setup from a truck or car to replace what I've got now. I even called March and asked about their serpentine system. The sales rep says, "Yeah, if you order it right now we'll waive the shipping and handling fees!" So I'm like, "How much?" The dudes like "$1199.00!!" I'm like, "For how many?" :rolleyes: So anyway..If anyone can offer any insight, please..PLEASE, send me an email or even call me!! ARGH!! Also to note, and I don't know if this matters, but I get a lot of belt vibration when the motor is decelerating (de-revving?) I don't know how to explain it better really..It just wobbles in the middle of the span between the alt and the water pump pulley. I don't know if this has anything to do with the fact that it keeps rolling over but I'm about to commit myself!! I am going to rebuild the motor after Santa brings my parts and I don't want a 4 dollar belt boiling a brand new engine!! Thank you all for your help. :mad :mad :mad :mad :mad :mad :mad :mad :mad :mad :mad

 

Real pain in the asse isn't it? This should get you on the path to good Karma:
http://shop.emotorstore.com/estore/td_techtips_vb.asp http://www.thirskauto.net/Fan_Belts.html</A> http://www.industrialtechnology.co.u...apr/gates.html <A HREF="http://www.maintenanceresources.com/ReferenceLibrary/V-Belts/Simple.htm" TARGET="_blank">http://www.maintenanceresources.com/ReferenceLibrary/V-Belts/Simple.htm

I had the same problem once also. Turned out to be a slight dent in the pulley was setting up an oscillation in the belt and with the long-run of the belt it was enough to cause it to pitch everytime I wound it out a bit.




[Modified by gerry72, 11:38 AM 12/5/2001]

 

Thank you for the reply. I see in the links where they suggest using an idler pulley. It would either have to be aftermarket or definitely fabricated. I will chec kto see if I have any dents in any of the pulleys. Hopefully thats all it is. This is absolutely driving me nuts. I am afraid to drive it cuz I don't need the belt flying off in traffic with no way to get over to the side to shut it down. I'm missing out on some good cruise time here. The weather has been outstanding! 80 degrees today! I was going to drive her to work today but when I popped the hood this morning to check fluids, the belt was twisted! :mad :cry :cuss

 

You sound like you've had your share of aggravation and I certainly don't want to push you over the edge, but can I ask the obvious question. Are you sure you have the belts aligned in the right groove on the crank? Are you set up the way the AIM shows the belt arrangement? If your belts are a groove off on the crank pulley they may be working at an angle. I'm at work so I can't check for you but I think the alternator belt on my 74 is the one closest to the engine with the A/C belt as the second. If these two are reversed it could be causing the problem since the belt would try to ride forward. Just thinking out loud but it might be worth checking. :seeya

 

Yeah, it's in the correct pulley groove. I'm not new to working on engines. I've had a few other projects (68 Camaro, 70 Chevelle, 69 Olds Cutlass) but dang if I don't get frustrated at things like this! I broke out the square and level and string and every other thing I could think of last time I replaced the belt. Once it turns over, the belt is wasted..it puts a "dent" in it. I think I'm going to look at the pulleys and make sure they are not dented anywhere. The thing that still puzzles me is the fact that the belt vibrates real bad after you snap the throttle and get the rpm's up..when the motor is coming back down the middle of the span between the alt and water pump pulley (the span on top) vibrates like mad!! :mad Like I said, I'm not sure if this has anything to do with it. Ooo, one more thing I forgot..even though it's a brnad new belt, it will squeal like a stuck pig for about 100 miles..then no more noise..I tried cleaning up the grooves of the pulleys to make sure there was no oil or anything in there. I even scuffed them slightly so the belt would grip it better. No joy! It's a good thing belts aren't expensive. I need to find some sanity in this thing..I don't want my rebuilt motor baked because of somehting stupid as this. Thank you all again for your insight and help :cry

 

Hi Nag78...
A couple of things.
1. The older vettes had a deep groove alt. pulley. I don't know if this was
carried to the newer models. Is your alt. original or has a it been replaced.?
Meaning, maybe your deep groove pulley went with the old one.
Also the pulley was not the "tin" type, it looks like a machined part.

2. I had a '69 Camero 350 that would do the exact same thing.
The problem was the type of belt I was using. If I put on a Gates, I could roll it at the first sign of high revs.
Someone suggested I use a belt with notches in it. I found one with
notches on the "V" side, and put it on. It could go to 7200 rpm without
a problem. (Sorry, too many years ago to remember the make).

On the vette now, I am using a belt with the notches on the top.
See picture below. Hope some of this helps.
Barry

 

Barry, that looks like Goodyear "Top Cog" belt on your car.

 

John
I think you are right. I couldn't remember what it was.
It's been on there for several years. It's seen 6500 rpm many times with
no problems. The old original Goodyear never had a problem either.
I think the alt. pulley makes all the difference. Given alignment and everything
else is fine.
Barry

 

OK, I've looked through three catalogs and Jeg's lists a Moroso deep groove alternator pulley for $25.99. It's part number 710-64800. It's listed as a 1 groove for GM, Ford and is cast. It uses a 36 degree x 17/32" wide belt.

They also list, from March, a polished aluminum kit for 71 - 82 Corvettes with V-Belts. It includes a 3 groove crank, 2 groove water pump and an alternator pulley w/cap for $212.99. It's part number 655-5070.
Hope this helps a little. :seeya

 

Barry, thank you for the input. I did replace the alternator and it did have the "small" pulley. I changed it out with the deep groove pulley though. You know, looking at the picture though, my belt doesn't sit as deep in the groove as yours does..I'm wondering if that could be a problem. When I went to the parts store for the first belt, they tried to give me this little dinky belt..I was like, I don't think thats it. The other belt they gave me was wider and deeper and filled the groove all the way. The flat side of the belt was flush with the edge of the pulley. Now that I look at your pic, I see that your belt sits pretty far down in the pulley. I will go back to the parts store and get the smaller belt and try it. Thank you all for your help. It keeps me out of the nut house! :crazy: :jester

 

Barry and John:
Hi. I was reading your comments and viewed the photo of the engine on Barry's car. Those "Top Cog" belts are made by Dayco. I use these belts on both of my Corvettes. ('75 Coupe L48 and '70 Convertable L46) Our friends use these Dayco Top Cog belts on their cars as well with good results.
David

 

David...
Welcome to the Forum. Thanks for keeping us honest on the belt.
I hope you enjoy the Forum. Most of us have lots of past/present experiences
(good and bad), I hope you will share some of yours as well.

Barry

 

Read about your belt problems and thought I would comment.
You mentioned that you didn't want a $4.00 belt causing you to ruin your engine. Remember that you get what you pay for. A cheap belt will not have the high speed stability that a good belt will have. They do not have as much fabric cord built into the belt and this is what gives the belt strength. Also belt tension is very important. In the middle of the span between two pulleys you should only be able to depress the belt about 1/4 of an inch. They do make a gauge for checking proper belt tension. I think they run about $10 dollars. I run Dayco "Top Cog" belts on our two corvettes, 75 coupe L-48 & 70 conv. L46. With good belts, proper pulley alignment & proper tension, you should be able to run 7,000 rpm without problems.One other thing, the shorter the belt you can run, the better. Good Luck!!!!!

David

 

Thanks for setting us straight on that one David. Come to think of it, you're correct, it is a Dayco. From what I remember, the cogs on the top of the belt are said to generate more airflow around the belt, keeping it cooler and lasting longer.

 

Thank you all for your help. I bought a Dayco top cog belt last night and will strap it on tonight. Keeping my fingers crossed that this will be the trick. If so, I will still be puzzled but oh well..I won't look a gift horse in the mouth :hat

"I get no kicks from champagne..mere alcohol doesn't thrill me at all..so tell me why should it be true..that I get a BELT :mad outta you!!" :jester