My caged lower pulley project

cozmo2806

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Well a couple years ago, cj428mach (Mike) and I were talking about the 4lb caged lower pulleys. We both had some good ideas, and left it at that. About a month ago, I decided to attempt to make a version of what we talked about. I was able to locate a piece of 6061 aluminum tubing with a 8.5"OD and 7"ID. Let me just say they are very proud of that stuff! But anyways I got it in and started making chips. What I did was machine off the ribs on the factory pulley, and made the new ring interference fit into the existing pulley. I then bolted the 2 together with 6 bolts. Final dimensions show about a 8.400 OD, which is probably closer to a 3-3.5lb pulley. Here are a few pics.

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cj428mach

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Looks good Sam, I'm so so so jealous of you to have the tools and know how to build something like this on your own.

Are you going to hard anodize it for wear? That aluminum can sure take a beating if its not protected.

Is the original lower tapped? or do the set screws just put pressure on the original pulley?
 
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cozmo2806

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Thanks for the compliments Mike! I'm going to try it like it is first. It is 6061 T6 so it should be pretty tough. We will have to see. Will definitely have to keep an eye on that.

Yes, I tapped the original holes along with the holes in the new ring. The screws run through the original and into the new piece. Screws are 1/2 inch long.
 

MG0h3

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Hope it works and nice job.

Id be concerned about shearing the bolts between the pulleys off.

Was the interference pretty tight?
 

mkb116

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We need someone with a 4.0 whipple to test one of these. If it holds up there it should be solid. Nice work!
 

cozmo2806

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Looks awesome nice work.

Thanks man!

Hope it works and nice job.

Id be concerned about shearing the bolts between the pulleys off.

Was the interference pretty tight?

Yea, I'm slightly concerned about that. The interference is .005, so its fairly tight. I also used the green retaining compound loctite. That along with 6 bolts I'm hoping is enough to hold.
 

cozmo2806

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We need someone with a 4.0 whipple to test one of these. If it holds up there it should be solid. Nice work!

Haha true, but I believe a 4.0 Whipple would break the drive plate piece before the outer ring lol.
 

oldmodman

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If you have any slipping/shearing problems you might want to go to a much greater interference and heat/freeze the parts so they slip over one another.

Might even be able to go as much as 35 thou. if you freeze the inner in dry ice and heat the outer on a hot plate to 400. Got a nice pair of gloves? :thumbsup:

Only one chance. Like putting sleeves in an aluminum block.
 

cj428mach

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Hope it works and nice job.

Id be concerned about shearing the bolts between the pulleys off.

Was the interference pretty tight?


The press fit should hold. It holds on a eaton/tvs when the hubs are pressed on those tiny shafts, the lowers have way way way more surface area. Thats why I thought this idea would work.

Here is my 2lb lower made with an LFP/Metco ring center machined out and pressed on a stock pulley.
15zgle9.jpg


Unfortunately the 4lb wouldn't work with out a bushing being made so I just went 2lb. Sam took it a step further and built his own ring. I believe my friend that made mine said the interference fit was .030 which sounds like a lot. He also staked it for feel good measure, lol.


I haven't put it to use yet because of the 4lb project.
 
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cozmo2806

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If you have any slipping/shearing problems you might want to go to a much greater interference and heat/freeze the parts so they slip over one another.

Might even be able to go as much as 35 thou. if you freeze the inner in dry ice and heat the outer on a hot plate to 400. Got a nice pair of gloves? :thumbsup:

Thanks for the input. Even with .005 thou I froze the steel piece for 3 hrs and baked the aluminum ring for 1.5 hrs at 280. It went together somewhat easy. Are you sure the .035 wouldn't be too tight to press together?


The press fit should hold. It holds on a eaton/tvs when the hubs are pressed on those tiny shafts, the lowers have way way way more surface area. Thats why I thought this idea would work.

Here is my 2lb lower made with an LFP/Metco ring center machined out and pressed on a stock pulley.
15zgle9.jpg


Unfortunately the 4lb wouldn't work with out a bushing being made so I just went 2lb. Sam took it a step further and built his own ring. I believe my friend said he the interference fit was .030 which sounds like a lot. He also staked it for feel good measure, lol.


I haven't put it to use yet because of the 4lb project.

Haha exactly what I tried to do with a 4lb metco ring. Just not enough meat there. We think alike. The 2lb setup looks good as well!
 

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