When replacing belts, does it matter which side of the belt runs on the pulleys? - JeepForum.com
 7Likes
Reply
 
LinkBack Thread Tools
post #1 of 16 Old 09-19-2019, 09:00 PM Thread Starter
Joncure
Registered User
1985 CJ7 
 
Join Date: Apr 2014
Location: Lexington
Posts: 261
When replacing belts, does it matter which side of the belt runs on the pulleys?

I'm about to replace the two belts on my engine (alternator and power steering). The old belts are installed with the smooth side down running on the pulleys with toothed side up. Does it matter which side is running on the pulleys, smooth or tooth side?

Joncure is offline  
Sponsored Links
Advertisement
 
post #2 of 16 Old 09-19-2019, 09:18 PM
BagusJeep
Web Wheeler
 
BagusJeep's Avatar
1981 CJ7 
 
Join Date: Jul 2009
Location: Bali
Posts: 6,973
Yes.

If you have a V belt it has a trapezoidal cross section, it is designed so that the triangle fits between the sides of the pulley, it does not touch the bottom/valley of the pulley. The force is transmitted through the friction of the two belt sides on the pulley sides, in a wedging action. Properly tensioned so it does not slip it can have power transfer up to about 95% efficiency. The belt should last about 3 to 4 years, before you start to risk sudden failure. A notched belt has grooves or notches across the bottom of the belt, which reduces the bending resistance of the belt. You are not using as much energy to bend them so they run cooler, last longer, and are about 2% more efficient than standard belts.

However, if you take that belt and turn it on is side (it is a triangle), you are now bending the top edge sideways, which it was not designed to do. The belt will wear and break.

If you turn it right over the only areas in contact with the pulleys is the two top edges. That is a very small area. The belt will slip, wear, not transmit efficiently, wear out and break.

PO had them on wrong!!!!
trailhead2004 and MikeyDeezy like this.

BagusJeep lives in Bali.

1981 CJ7 258ci - Bagusjeep
1984 CJ7 258ci - Puthijeep
1981 J20 258ci - Gladys
1951 Willys CJ3A/MB/M38 - Little Willy
1995 Cherokee 4.0 - CHEROKEE
BagusJeep is offline  
post #3 of 16 Old 09-20-2019, 04:39 AM
John Strenk
Moderator
 
John Strenk's Avatar
1976 CJ5 
 
Join Date: Feb 2005
Location: Shalersville Ohio
Posts: 19,163
I would love to see a picture of how the belts were mounted.

Could having the pulleys miss-aligned cause them to flip?
trailhead2004 likes this.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
John Strenk is offline  
 
post #4 of 16 Old 09-20-2019, 05:01 AM
Thrasonic
Registered User
 
Join Date: Sep 2019
Posts: 3
Can you post a picture to show how the belts are mounted?
trailhead2004 likes this.
Thrasonic is offline  
post #5 of 16 Old 09-20-2019, 05:44 AM
jeepdaddy2000
Registered User
 
jeepdaddy2000's Avatar
1971 CJ5 
 
Join Date: Jan 2002
Location: Eagle Point
Posts: 8,269
A quick FYI on "toothed" belts.

The "teeth" are actually reliefs molded into the belt to aid it in bending through the acute arcs that the belts sometimes have to get around on pulleys. Any time you see a V belt with "teeth", they always go down/inward.
Attached Images
 
trailhead2004 and MikeyDeezy like this.

The duty of a patriot is to protect his country from it's government
Thomas Payne
jeepdaddy2000 is offline  
post #6 of 16 Old 09-20-2019, 09:28 PM Thread Starter
Joncure
Registered User
1985 CJ7 
 
Join Date: Apr 2014
Location: Lexington
Posts: 261
Thanks for the input everyone. The belts that are on there are the same since I bought the jeep in 2014. I hope the pulleys are not misaligned, but not sure why there were installed that way. Glad I asked....here is a picture...
Attached Thumbnails
IMG_0043.jpg  
Joncure is offline  
post #7 of 16 Old 09-20-2019, 09:49 PM
Axhammer
Registered User
 
Axhammer's Avatar
1985 CJ7 
 
Join Date: Aug 2018
Location: Moyock
Posts: 453
Garage
Quote:
Originally Posted by Joncure View Post
Thanks for the input everyone. The belts that are on there are the same since I bought the jeep in 2014. I hope the pulleys are not misaligned, but not sure why there were installed that way. Glad I asked....here is a picture...
Those belts in your picture have the ribs on top, they are installed correctly, they look good, there is nothing wrong with that installation. Your P/S pulley looks like it is out of alignment slightly, but it’s hard to tell from that picture. The P/S pulley also looks like it is bent slightly. That may or may not affect operation, depending on where and how much it is bent. Take the belt off and spin the pulley by hand and watch for wobble. You can put a straight edge on the balancer pulley to verify alignment with other pulleys, it’s easy to do, and usually best to do it with the belts removed. All you have to do is add washers as shims where needed to bring it back into alignment. If they’ve been run for five years, without trouble, they are OK, most likely.

The belts in the other picture are a completely different style belt. They are not the same belts you have.

I have the style in your picture installed on my race car, I put an alternator on it several years ago, and it looks just like your picture. It gets run to 6000 RPM several times every pass, and it has never thrown a belt. But, I did assure pulley alignment with a straight edge so it wouldn’t throw the belt. I’ll post up a picture of my race set-up tomorrow.

1985 CJ-7 Red with white hardtop, 258 auto
View my Pontiac in my profile
Axhammer is offline  
post #8 of 16 Old 09-21-2019, 07:50 AM Thread Starter
Joncure
Registered User
1985 CJ7 
 
Join Date: Apr 2014
Location: Lexington
Posts: 261
Thanks for the input Axhammer. I can't see the other pictures on this thread for some reason, so I can't compare my picture with it. But at this point, I'm still confused about my belt installation situation. Some say they're installed incorrectly and you say they are not. Can you or anyone else clarify some more either way?
Joncure is offline  
post #9 of 16 Old 09-21-2019, 08:09 AM
jeepdaddy2000
Registered User
 
jeepdaddy2000's Avatar
1971 CJ5 
 
Join Date: Jan 2002
Location: Eagle Point
Posts: 8,269
Quote:
Originally Posted by Joncure View Post
Thanks for the input Axhammer. But at this point, I'm still confused about my belt installation situation. Some say they're installed incorrectly and you say they are not. Can you or anyone else clarify some more either way?
Axhammer is correct(good job on posting a picture). Your belts are ribbed on the back facing. That is different than a "toothed" belt which has large ribbing on the inside V. Your style belt is not a common design. There is no great advantage to your belts so feel free to chuck them if they are bad.

Quote:
I can't see the other pictures on this thread for some reason, so I can't compare my picture with it.
Google "toothed automotive v belt"and click on images to see the difference.

The duty of a patriot is to protect his country from it's government
Thomas Payne
jeepdaddy2000 is offline  
post #10 of 16 Old 09-21-2019, 08:13 AM
pedal2themetai
Registered User
1956 CJ5 
 
Join Date: Apr 2015
Location: Boise
Posts: 1,276
HI, if your belt has a V shape to it the V goes INTO the pulley . The ribbing on your belt is just to add in keeping it pliable to bend around the pulleys and IS on the outside of the belt. Yours are installed correctly... a serpentine belt does have ribs on the inside .. Yours is NOT a serpentine system
good luck
tim
pedal2themetai is offline  
post #11 of 16 Old 09-21-2019, 09:29 AM
Axhammer
Registered User
 
Axhammer's Avatar
1985 CJ7 
 
Join Date: Aug 2018
Location: Moyock
Posts: 453
Garage
Here is a picture of my Pontiac race engine. On the radiator there is a piece of piano hinge that I use for a straight edge. Notice the washers on the Alternator mount used to achieve correct alignment.
Attached Images
 

1985 CJ-7 Red with white hardtop, 258 auto
View my Pontiac in my profile
Axhammer is offline  
post #12 of 16 Old 09-21-2019, 09:32 AM
Axhammer
Registered User
 
Axhammer's Avatar
1985 CJ7 
 
Join Date: Aug 2018
Location: Moyock
Posts: 453
Garage
Closer view.
Attached Thumbnails
4D8E9101-AA53-4EBA-A0BD-64D726BA9B21.jpg  

1985 CJ-7 Red with white hardtop, 258 auto
View my Pontiac in my profile
Axhammer is offline  
post #13 of 16 Old 09-21-2019, 09:42 AM
Axhammer
Registered User
 
Axhammer's Avatar
1985 CJ7 
 
Join Date: Aug 2018
Location: Moyock
Posts: 453
Garage
With a straight edge on the crankshaft pulley, notice the alternator pulley is parallel, and the belt is too. If you take the time to achieve this kind of pulley alignment, you will not have belt problems.

Our Jeeps are 34+ years old. Nothing is going to go together with the same tolerance as it did when new. It takes this kind of attention to detail to achieve results...a good running, maintenance free & reliable vehicle. The beauty is, when you get everything right it is reliable and old at the same time. There is nothing better than daily driving a CJ-7 in my opinion.

On a side note: This Pontiac is even older, it’s a 1969 with a 1973 block.
Attached Thumbnails
E443028D-662B-4FC5-AD79-0D5C46CC93C3.jpg  
pedal2themetai likes this.

1985 CJ-7 Red with white hardtop, 258 auto
View my Pontiac in my profile
Axhammer is offline  
post #14 of 16 Old 09-22-2019, 10:20 AM Thread Starter
Joncure
Registered User
1985 CJ7 
 
Join Date: Apr 2014
Location: Lexington
Posts: 261
Thanks everyone, always an education and never boring!
Joncure is offline  
post #15 of 16 Old 09-22-2019, 06:02 PM Thread Starter
Joncure
Registered User
1985 CJ7 
 
Join Date: Apr 2014
Location: Lexington
Posts: 261
Well I finally got a view of the brand of belt on my engine; Dayco Top Cog V-belt. So they were installed correctly and designed that way. I may try to replace with the same brand. Who knows how long they have been on there, I've owned it for 5 years now and they are just now showing some cracks between the cogs. Thanks again for all the quick and very helpful replies.
Joncure is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.



Email Address:
OR

Log-in











Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome