Poor man's method to better belt wrap on an fbody
#61
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edit... now that I think of it it scraped right around the time the bearings in that idler went out, might have been that too.
Last edited by Avengeance; 10-26-2009 at 10:09 AM.
#62
The step down is not so much required, but the spacer is very necessary. You don't want the pulley walking forward any and contacting the bracket. I just had that section at the end machined down to accommodate a common washer size that I was able to pick up at Lowes for cheap. If you wanted to have a custom spacer machined, or could find an oddball washer that will fit over the .668 section and still have an OD that will fit inside the pulley, then no, you don't have to machine down the end like that.
#63
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The step down is not so much required, but the spacer is very necessary. You don't want the pulley walking forward any and contacting the bracket. I just had that section at the end machined down to accommodate a common washer size that I was able to pick up at Lowes for cheap. If you wanted to have a custom spacer machined, or could find an oddball washer that will fit over the .668 section and still have an OD that will fit inside the pulley, then no, you don't have to machine down the end like that.
#68
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I went and looked at my photos.. I took this pic in March 05. A lot has changed since then.
#71
TECH Apprentice
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You may find yourself running into belt size problems on this set-up though depending on what size pulleys you are running. I had no issues with a 3.7" BP/ 7.65" CP. Gates made a belt that fit perfectly (K080415 i think) and tightening the belt left a perfect gap between the two idlers with room to tighten more. Once I stepped down to a 3.55" BP, things got a little trickier. The K080415 belt had to be tightened all the way to where both idlers where almost touching each other to get the proper tension. You couldn't squeeze a piece of paper between the idlers they were so close together.
Moving to the next smaller sized belt K080408 didn't work. The belt was too short to install. A 3.4" BP would've been the only other option or a custom belt. All in all though, this mod is definitely worth it 100%.
#72
Here ya go Ricky:
7.25/3.4/2.5/3.0/40.35/216°/263°
7.25/3.4/2.5/2.5/40.09/213°/259°
Your best bet here is probably going to be the 2.5/2.5 setup because gates makes a 40.0" belt
Very true. The adjustment range with this setup is very narrow, so your belt needs to be almost spot on. However, switching out idler pulleys between 2.5" and 3" can help a little bit.
Man, thats awesome news! I'm planning to run a 3.7 pulley in the future, and you just verified my calculations were correct about a 41.5" belt fitting that application
You may try swapping out your procharger 2.5" idler for a 3" stock accessory idler like I am using and see if that works. I know by doing this, you lose a little bit of adjustment because of the bigger pulley, but it also will take up more belt length.. According to my calcs, a 7.65/3.55/2.5/2.5 like you have now would ideally require a 41.28" belt. With a 7.65/3.55/2.5/3.0 I'm coming up with a 41.56" belt. If I were you, I'd take the stock accessory idler off, then put it on your standoff and see how well it works with your 41.5" belt. I had to space the accessory idler out away from the hex by .1" to get it lined up with the belt, but see what works for you. Keep in mind that the stock accy idler is about the exact same width as an 8 rib belt, so its alignment needs to be pretty close. I used some wheel lug nut washers from my convo pro wheels which was a nice fit over the shaft part of the standoff and a small enough OD to still fit inside the pulley. I know they aren't really a commonly available part, but do whatever works. I am pretty sure that should help you out and create some more clearance between your pulleys. And for a $20 part at Oreilleys, a cheap easy solution.
If that doesn't work for you, you can go with a 3.4 blower pulley, and a 7.25 crank pulley and use a 40" belt with a 2.5 idler and 2.5 tensioner as I posted the sizes above for Ricky. A 7.25/3.4 combo is virtually the same ratio as a 7.65/3.55 combo. The 7.25 pulleys are common from the SDCE setups, and also I believe Vortech uses a 7.25 8 rib crank pulley. Hope this helps some.
7.25/3.4/2.5/3.0/40.35/216°/263°
7.25/3.4/2.5/2.5/40.09/213°/259°
Your best bet here is probably going to be the 2.5/2.5 setup because gates makes a 40.0" belt
Once I stepped down to a 3.55" BP, things got a little trickier. The K080415 belt had to be tightened all the way to where both idlers where almost touching each other to get the proper tension. You couldn't squeeze a piece of paper between the idlers they were so close together.
Moving to the next smaller sized belt K080408 didn't work. The belt was too short to install. A 3.4" BP would've been the only other option or a custom belt. All in all though, this mod is definitely worth it 100%.
Moving to the next smaller sized belt K080408 didn't work. The belt was too short to install. A 3.4" BP would've been the only other option or a custom belt. All in all though, this mod is definitely worth it 100%.
If that doesn't work for you, you can go with a 3.4 blower pulley, and a 7.25 crank pulley and use a 40" belt with a 2.5 idler and 2.5 tensioner as I posted the sizes above for Ricky. A 7.25/3.4 combo is virtually the same ratio as a 7.65/3.55 combo. The 7.25 pulleys are common from the SDCE setups, and also I believe Vortech uses a 7.25 8 rib crank pulley. Hope this helps some.
#76
I'm trying to source the standoffs now. So far I've had virtually zero luck finding a source for a 19mm hex standoff with a M10x1.5 thread thats 75mm long. I can't find it in ANY material, much less stainless. I've only found one place so far that would do it, but they have a $500 minimum order. They would sell me 25 @ $20 each, or 100 @ $10 each. Needless to say I don't really have money on hand to invest in that many standoffs. I need to get the material before I can get a quote from the machine shop to machine it. Heck, if I could find even an unthreaded standoff with just a smaller hole in it than is required, I could have it tapped with the correct thread size, thats not a huge deal, but I can't even find that out there. Even a 3/4" standoff 3" long with a thru hole smaller than 3/8" could work for that proceedure, but can't find those either.
Only other solution I could come up with is to get a group of 10 or so guys to ship me their aluminum standoffs, and I can have them all machined at the same time, but I'm not sure too many people would be willing to do that. Maybe now is a good time since its winter but everyone would have to coordinate to get their standoffs shipped at the same time to keep cost down. If machined individually, I'm sure it would cost a little more, but at that point, people may as well just have their own local machine shop do it for them... So I dunno..
Only other solution I could come up with is to get a group of 10 or so guys to ship me their aluminum standoffs, and I can have them all machined at the same time, but I'm not sure too many people would be willing to do that. Maybe now is a good time since its winter but everyone would have to coordinate to get their standoffs shipped at the same time to keep cost down. If machined individually, I'm sure it would cost a little more, but at that point, people may as well just have their own local machine shop do it for them... So I dunno..
#77
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I'm trying to source the standoffs now. So far I've had virtually zero luck finding a source for a 19mm hex standoff with a M10x1.5 thread thats 75mm long. I can't find it in ANY material, much less stainless. I've only found one place so far that would do it, but they have a $500 minimum order. They would sell me 25 @ $20 each, or 100 @ $10 each. Needless to say I don't really have money on hand to invest in that many standoffs. I need to get the material before I can get a quote from the machine shop to machine it. Heck, if I could find even an unthreaded standoff with just a smaller hole in it than is required, I could have it tapped with the correct thread size, thats not a huge deal, but I can't even find that out there. Even a 3/4" standoff 3" long with a thru hole smaller than 3/8" could work for that proceedure, but can't find those either.
Only other solution I could come up with is to get a group of 10 or so guys to ship me their aluminum standoffs, and I can have them all machined at the same time, but I'm not sure too many people would be willing to do that. Maybe now is a good time since its winter but everyone would have to coordinate to get their standoffs shipped at the same time to keep cost down. If machined individually, I'm sure it would cost a little more, but at that point, people may as well just have their own local machine shop do it for them... So I dunno..
Only other solution I could come up with is to get a group of 10 or so guys to ship me their aluminum standoffs, and I can have them all machined at the same time, but I'm not sure too many people would be willing to do that. Maybe now is a good time since its winter but everyone would have to coordinate to get their standoffs shipped at the same time to keep cost down. If machined individually, I'm sure it would cost a little more, but at that point, people may as well just have their own local machine shop do it for them... So I dunno..
#79
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I did this my self several years ago had a extra idler pulley so had a stand off machined down works great! anyone who would like this done just drop me a PM and i can do it for them.
also if you do this you no longer have to take the blower off to change the belt.
also if you do this you no longer have to take the blower off to change the belt.
Last edited by 01red28; 10-27-2009 at 10:40 PM.