69 big block with ac idler pulley belt routing question

[stanvette]

Hello Friends, I am restoring my 69 big block with ac and no power steering. The car is very original with only about 25 K miles but the belts have been changed in the past with non correct belts . When i removed the belts the idler pulley was pushed against the outside of the belt. I ordered the new correctly marked belts and found that the new belt was to big so i looked in my assembly manual and it shows the belt going on the outside of the pulley. Now the new belt is to short to do that. I called a corvette tech and he said the pulley should go on the outside of the belt . I am not sure who to believe the assembly manual or the tech i spoke with. Please advise what is correct. Has any one else run into this and if so where did you get the correct belt either way i need a different belt. Please help. Thanks Stan

 

[toobroketoretire]

Hello Friends, I am restoring my 69 big block with ac and no power steering. The car is very original with only about 25 K miles but the belts have been changed in the past with non correct belts . When i removed the belts the idler pulley was pushed against the outside of the belt. I ordered the new correctly marked belts and found that the new belt was to big so i looked in my assembly manual and it shows the belt going on the outside of the pulley. Now the new belt is to short to do that. I called a corvette tech and he said the pulley should go on the outside of the belt . I am not sure who to believe the assembly manual or the tech i spoke with. Please advise what is correct. Has any one else run into this and if so where did you get the correct belt either way i need a different belt. Please help. Thanks Stan

The big blocks used a "minimum length" 1/2" belt that barely went over the crank and water pump pulleys. Then the flat 4" idler pulley pushed AGAINST the outside of the belt right between the two pulleys. The idler pulley was missing on my big block '71 so I made my own; using a 4" 4-Seasons idler pulley then I mounted it on the right side of my water pump so the pulley could pull on the belt. It's mounted on an eccentric adjustment hub so I can tension the belt.

 

[SVO]

I have a 69 & a 72 BB. The idler belt on both of my cars is a Gates #17330. Your local parts house may not carry Gates belts, but they should be able to cross that belt number over to whatever brand they do carry. As noted, the idler runs on the outside of the belt. That is, the belt runs between the crank pulley/water pump pulley and the idler. What is shown in the assembly manual is correct. The belt is the same wheter the car has power steering or not.

The fastest way to confuse a parts counter is to ask for a replacement set of belts for a big block. Power steering and air conditioning just add to the confusion.

Should you need numbers for your other belts, let me know.

 

[stanvette]

Thanks so much

The big blocks used a "minimum length" 1/2" belt that barely went over the crank and water pump pulleys. Then the flat 4" idler pulley pushed AGAINST the outside of the belt right between the two pulleys. The idler pulley was missing on my big block '71 so I made my own; using a 4" 4-Seasons idler pulley then I mounted it on the right side of my water pump so the pulley could pull on the belt. It's mounted on an eccentric adjustment hub so I can tension the belt.

Thank You i will get it fixed