How to Lighten CV Joints?

While I realize the most cost-effective weight reduction in FF involves the driver, at a recent race while lamenting my sumo status one of my colleagues exclaimed "your CV joints are not even lightened"!

So looking for info on how I lighten them this winter. I assume it involves either a drill press or a lathe, both of which I have access to

Thanks

Call your supplier of choice: Taylor, Fast Forward, Pro Tech, TDI, & Williams all have a version of the std Lobro CV joint application used on older cars. It is not quite as simple as just putting the housing into the lathe and removing material.

Of course salads and bicycling work well too:)

Sorry, double posted.

http://www.apexspeed.com/forums/./Images/L/1473.JPG

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Originally Posted by Rondo

While I realize the most cost-effective weight reduction in FF involves the driver, at a recent race while lamenting my sumo status one of my colleagues exclaimed "your CV joints are not even lightened"!

So looking for info on how I lighten them this winter. I assume it involves either a drill press or a lathe, both of which I have access to

Thanks

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Read this info from Pegasus;

http://www.pegasusautoracing.com/pro....asp?RecID=292

Honing the grooves is NOT recommended by GKN, even though most people do it and get away with it just fine.

The better way is to replace the balls with some .002" smaller in diameter to loosen it back up. That way, when it finally gets sloppy again in a couple of years, you just put the original balls back in.

I've had good success with lightening used CV joints. I figured the untold thousands of miles loosened up the assembly, so machining the OD tightens them up again. I use redline CV grease.

The reason not to rehone the grooves is that it removes the case hardening in them and accelerates wear.

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Originally Posted by 10rmotor

I've had good success with lightening used CV joints. I figured the untold thousands of miles loosened up the assembly, so machining the OD tightens them up again. I use redline CV grease.

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Let's see: lighten it yourself, cost = 0.00. Buy lightened joints, cost = $239.99 each. What to do, what to do?

I have an old used CV joint to practice on lightening. Does anyone know where I can get a drawing of a lightened joint so I don't remove too much metal.

Hope this helps - I measured a couple of lightened CV's, which gave up the following:

Width of machined 'valley' = 1" central
Depth of 'valley' = 7/32"

The depth was measured against the smaller diameter end of the standard Lobro joint and it has a good radius on both sides.

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Originally Posted by tlracer

Hope this helps - I measured a couple of lightened CV's, which gave up the following:

Width of machined 'valley' = 1" central
Depth of 'valley' = 7/32"

The depth was measured against the smaller diameter end of the standard Lobro joint and it has a good radius on both sides.

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That definitely helps! Was this a joint that you lightened or a bought item?
I am considering two methods of machining:
1. On a lathe with a radius formed tool.
2. On a rotary table on a mill with a ball end mill.

I'd have to have a joint here to measure, but if I remember correctly ( it's been 20 years or so since I last did one), I machined about 1/2 way thru the bolt holes, leaving about .125 - .150 thick ends, with a .125 radius between the reduced diameter and the ends.It lightened the joint about 5/8th of a pound. We used .001 or .002 smaller balls, which were swapped out for the original balls after about 2 years of use.

A lathe is the easiest way to do these.

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Originally Posted by T644HU07

That definitely helps! Was this a joint that you lightened or a bought item?
I am considering two methods of machining:
1. On a lathe with a radius formed tool.
2. On a rotary table on a mill with a ball end mill.

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One was a proper job, the other was perhaps best described as a 'home made' version (not mine, it came with a car, some years ago). Dimensions were similar on both but the 'proper' one had a much more acceptable radius.

The relieved 'valley' does indeed go half way through the bolt drilling.

As the esteemed Mr Pare says, doing the work on a lathe is the easiest!

I do it on a manual lathe. See my build thread for a couple of pictures. Dimensions on how much to remove are sort of up to your risk management level.

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Originally Posted by patman

I do it on a manual lathe. See my build thread for a couple of pictures. Dimensions on how much to remove are sort of up to your risk management level.

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Couldn't find your build thread. Could you provide a link?

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Originally Posted by formulasuper

Read this info from Pegasus;

http://www.pegasusautoracing.com/pro....asp?RecID=292

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I have tried these lightened ones from Pegasus and have seen a much higher failure rate. How has others experience been with these?

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Originally Posted by halcyon

I have tried these lightened ones from Pegasus and have seen a much higher failure rate. How has others experience been with these?

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What failed? I have not used these but the only failure I've seen on the standard joints was cracking in the cage.

I seem to remember one secret to stopping cage cracking is to take a cartridge roll and radius all the stamped edges in the cage.

I wish I could buy replacement cages when I used the CV's. Have lots of CV's with cracked cages somewhere in the shop.

Ed

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Originally Posted by Rick Kirchner

I seem to remember one secret to stopping cage cracking is to take a cartridge roll and radius all the stamped edges in the cage.

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Rick, that is exactly what I do to mine!

And FWIW, I do them on my lathe, and have probably done a dozen will no ill effect in use. And yes, I polish the grooves as well. Having said that, I came upon a couple of them that were just too hard to cut despite having done this before, fresh bit, fluid, etc. No matter what I tried (speed, feed) I just burned the bit. It was as if they were made "harder" than normal, if that makes sense?

bt