Serpentine belt tension

Zambo

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So we've been having a discussion around the shop about the tensioner pulley for the serpentine belt in our truck. We've had some belt slipping/breaking issues, probably due to an incorrect pulley but we've also been looking at the tensioner.

Some of us think that the tensioner isn't strong enough to keep our belt from slipping during the heavy loads we put on the motor and the idea to fix it was to weld an extension onto the tensioner arm that we could then use to apply a little extra tension and then lock into position (much like you do when you rotate an alternator and put tension on a v belt setup).

On the other hand some of us were wondering if locking down a serpentine belt would have negative effects if the belt stretched during use or expanded due to heat, seeing as how the back side of the belt drives smooth pulleys, unlike a v belt. If so, the tensioner now being locked down wouldn't be able to take up the slack.

What say you oh wise familia?
 
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We use a Katech tensioner on our LS1, after repeated issues in testing showed the stock setup inadequate for our usage. We have had no belt troubles in several thousand miles since making the change.
 

BroadSword

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Bringing this back to the top. I have recently been experiencing belt tension issues with the stock GM auto tensioner. What aftermarket fixed tensioners are people using and how are they holding up? Thanks.
 
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Katech. No issues over several seasons.
 

D.Mavis

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If you use a fixed tensioner what belt tension do you run? I have seen v belt tension testers is there an equivalent for serpentine?


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MCM MOTORSPORTS

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Comp Cams make a good billet tensioner. You use a 3/8 ratchet to put tension on it, then do a lock bolt up. Not too badly priced either.
 

gawdodirt

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The stock tensioner is made for loads seen in production testing. Pulley ratios, and inertial loads all with stock components. The installation diagrams were designed for that application. Thinking that a production tensioner will suffice in a modified condition is, well, not wise. Neither will locking it down solid as the belt will stretch when hot and there is less latitude with a serp belt than a V-belt. I would look into all solid mounted idlers and tension from the back, or or smooth side, with a spring loaded smooth pulley. Not sure anyone makes one of these yet, but there's your idea.

GD
 
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