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| | | | Joined: Sep 2007 Posts: 46 Wrench Fetcher | | Wrench Fetcher Joined: Sep 2007 Posts: 46 | When I put a 261 in my 39 1/2 ton I also upgraded to a alternator. The belts scream at me when I give it gas. If I drive like an old lady it does not make a noise. I put on a new belt and the belt is tight. The alternator is new but I did not change any pulleys. What have I over looked? The belt noise is driving me nuts.
Scott | | | | | Joined: Feb 2004 Posts: 29,799 Kettle Custodian (pot stirrer) | | Kettle Custodian (pot stirrer) Joined: Feb 2004 Posts: 29,799 | Try fitting a larger-diameter pulley to the alternator, if you can find one. Sometimes the belt contact area around the pulley isn't sufficient for the belt to get enough traction. If the crankshaft pulley is very large in relation to the alternator pulley, it might be trying to drive the armature too fast. A glazed belt surface is another possibility, if the squeal has been going on for some time.
How much of the belt is wrapped around the alternator pulley? If you install a longer belt and a longer adjuster bracket, there will be more belt wrapped around the pulley, which translates to more traction.
Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!
| | | | | Joined: Nov 2005 Posts: 238 Shop Shark | | Shop Shark Joined: Nov 2005 Posts: 238 | Had the same problem on my truck after starting from cold right from when I bought it. I checked all the usual stuff, belt not bottoming in any of the pulley vees etc. I could only get rid of it by running the belt very tight, wasn't happy with this as I didn't think the water pump or alternator bearings would last. I changed to this twin vee belt setup and that cured the problem straight away. perhaps you could get twin belt pulleys for your straight six if all else fails. Stuart. | | | | | Joined: Feb 2004 Posts: 29,799 Kettle Custodian (pot stirrer) | | Kettle Custodian (pot stirrer) Joined: Feb 2004 Posts: 29,799 | Finding a 2-belt crankshaft damper for a 235/261 engine is going to be a challenge. You'd also need a water pump with a second pulley groove to take that approach to solving the problem.
Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!
| | | | | Joined: Feb 2001 Posts: 1,094 'Bolter | | 'Bolter Joined: Feb 2001 Posts: 1,094 | Scott, the 261 may have a wider belt than the alt. pulley. If you have the generator look at the width of the pulley. I think you can just swap the pulley.
Tommy
59 apache 1/2t
261 short stepside
| | | | | Joined: Aug 2011 Posts: 194 Shop Shark | | Shop Shark Joined: Aug 2011 Posts: 194 | It sounds to me like a bearing needs to be re-greased or has gone out on one of the pulleys which makes it squeal. You can buy bearings at your local Tractor Supply or auto supply store. Good luck, and let us know what happens! | | | | | Joined: Jan 2009 Posts: 1,644 Shop Shark | | Shop Shark Joined: Jan 2009 Posts: 1,644 | Jim Carter sells the wide pulley for the alt.I put one on mine.
Pete | | | | | Joined: Mar 2008 Posts: 3,750 'Bolter | | 'Bolter Joined: Mar 2008 Posts: 3,750 | Mine were OK until I painted the pulleys,then the screeching started.
I scuffed up the contact area where the belts go with a Scotchbrite pad,problem sorted......
1950 Chevy Advance Design 3100 in ScotlandIn the Stovebolt GalleryMore pix on Flickr. I've definately got this truck thing in my blood ... my DNA sequence has torque settings"Of all the small nations of this earth,perhaps only the ancient Greeks surpass the Scots in their contribution to mankind" Winston Churchill.
| | | | | Joined: Dec 2008 Posts: 319 Shop Shark | | Shop Shark Joined: Dec 2008 Posts: 319 | A little belt dressing would help.
cm
If you can't fix it with a hammer and screwdriver, you need a bigger hammer.1965 Chevy C10 | | | | | Joined: Sep 2004 Posts: 201 'Bolter | | 'Bolter Joined: Sep 2004 Posts: 201 | Do all the pullys line up? is the altinator off? | | |
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