How to measure belt length?

Thread Tools
 
Search this Thread
 
Old May 2, 2011 | 04:45 PM
  #1  
defiant1's Avatar
Thread Starter
Registered User
 
Joined: Jan 2010
Posts: 1,003
Question How to measure belt length?

Moved alternator to other side of motor. Now original belt is too short. What is the most accurate way to measure the belt length around the pulleys? Wire, string, etc.?

Granted the alternator is adjustable so I have room for error but would like to get it close as possible.

Thanks

d1
Old May 2, 2011 | 04:59 PM
  #2  
citcapp's Avatar
Registered User
 
Joined: Nov 2007
Posts: 9,127
From: Rathdrum, Idano
I cut a too long used belt and put it around the pulleys and then measure it. This has always worked well for me
Old May 2, 2011 | 06:01 PM
  #3  
defiant1's Avatar
Thread Starter
Registered User
 
Joined: Jan 2010
Posts: 1,003
Ok, I'll see what I have laying around. I got plenty of serpentine, but not sure of v-groove.
Old May 2, 2011 | 06:09 PM
  #4  
defiant1's Avatar
Thread Starter
Registered User
 
Joined: Jan 2010
Posts: 1,003
I think I am overthinking this...

Since I am mounting the alternator on the driver's side with the bracket and brace for a 1970 Cutlass what part # belt do you all use? I have an A/C (aftermarket) car and instead mounting the alternator to the drivers side, they mounted it under the A/C.

So, I am assuming that the alternator belt goes around the crank pulley and around the fan belt pulley and finally around the alternator pulley (one big oblong circle). If that is correct, then I should be able to order the "factory" belt?

If anyone has a part number, I would appreciate it.

d1
Old May 2, 2011 | 07:33 PM
  #5  
MDchanic's Avatar
Connoisseur d'Junque
 
Joined: Sep 2010
Posts: 21,183
From: The Hudson Valley
Originally Posted by defiant1
So, I am assuming that the alternator belt goes around the crank pulley and around the fan belt pulley and finally around the alternator pulley (one big oblong circle). If that is correct, then I should be able to order the "factory" belt?

If anyone has a part number, I would appreciate it.
Here are pics of the driver's-side-alternator belts for a '70 Cutlass...

350:


455:



The GM numbers you're looking for appear to be
391213 without P/S or 406086 with P/S for a 350, or
399628 with or without P/S for a 455.

You should be able to cross reference them in any auto parts store book - Dayco, Gates, etc.
Sizes can be found here:




- Eric
Attached Images
File Type: jpg
1970 350 Belts.jpg (109.4 KB, 76 views)
File Type: jpg
1970 455 Belts.jpg (104.3 KB, 71 views)
File Type: jpg
Alt. Belts by Length.jpg (109.7 KB, 73 views)
Old May 2, 2011 | 07:52 PM
  #6  
defiant1's Avatar
Thread Starter
Registered User
 
Joined: Jan 2010
Posts: 1,003
Eric, thanks for taking the time to post this info. I imagine, not only will it help me but others as well.

Shaun
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
bassinguy
General Questions
4
Mar 21, 2014 02:01 PM
coldfire
Wheels and Tires
7
Jul 22, 2013 05:49 PM
Olds98
General Questions
0
Aug 6, 2010 05:02 AM
DAN76
Big Blocks
7
Jul 30, 2009 05:53 AM
Sixoh
Chassis/Body/Frame
1
Aug 21, 2006 07:50 AM




All times are GMT -7. The time now is 03:13 PM.