Having just a little "working" knowledge of these things can definitely lead to false conclusions. So, I assume that the blower pulley itself has enough tension/pressure on its actuation (closing and opening, going from large diameter to small diameter) from the drive inside the housing, that the tension on the spring pack really plays no role in its movement, etc.

Therefore, I would also assume from what you are telling me that I need to get a belt that will fit the unit as close as I can get the spring pack to compress...upon initial installation (allowing for the minimum diameter of the blower pulley to have good friction on it because the spring pack is still holding it snugly around all of the pulleys in question)...now that's a mouthful!!

I will check out Chuck's belt first and go from there.

Daniel Jessup

Lancaster, California

aka "The Hot Rod Reverend"
check out the 1955 Ford Fairlane build at www.hotrodreverend.com

Thanks john, Dan and I both had same question re belt tension, you have made it clearer, guess i,ll go and try some belts. Thanks for the information. Regards bill.  

  AussieBill            YYYY    Forever Y Block     YYYY

 Down Under, Australia

Just a bit of added information.  When the blower is told it needs to put out more boost, it reduces the pressure against the piston that actuates the variable speed pulley.  The belt then tries to wedge itself deeper in the pulley, thereby pushing the piston out of the way so the blower will spin faster.  When boost reaches the preset value, the piston again closes the pulley and the belt has no choice but to ride higher in the groove by compressing the tension spring.  Hope this makes sense.

John - "The Hoosier Hurricane"

John, thanks for your vast knowledge on this subject and expeirence racing these units. So if i had a belt too long, it would not place enough tension on blower pulley, then one too short would overload the bearings and pulleys, then to be in the ballpark would i be correct with a belt that compressed the tensioner spring about 3/4 of its travel? Just need a starting point, thanks again. regards bill.

  AussieBill            YYYY    Forever Y Block     YYYY

 Down Under, Australia

Your plan sounds like a good one.  And Paul, I had one of those combines, and my present Gleaner also has variable speed pullies.  But my variable speed belt drive experience comes from several years of maintenance supervision in an industrial plant.

John - "The Hoosier Hurricane"