I'm preparing to replace CVs for the coming season and this time, rather than just replacing Lobro with Lobro, I'd appreciate input from members about alternatives and opinions regarding the various brands.
Also, How much grease should you really use in a CV/boot???
Thanks.
Gary Payne
St Louis
[size="1"][ 02-08-2003, 04:44 PM: Message edited by: Gary Payne ][/size]
The newer Van Diemen cars in the UK use the tripod joints manufactured by GKN. These are much stronger, they rely on a needle roller bearing assembly and do not have the weak point of the earlier design which is the cage. Unfortunately they are not a direct swap with the cage and ball design but I'm sure any competant machine shop could come up with a conversion. They are also cheaper to buy!
The lobro stuff is pretty tried and true. A switch to another setup is possible but not trivial. Better just to lighten your current setup by putting the housing in a lathe and removing material from the OD. There may not be much of a gain from switching to a completely different setup. How much grease? Look at it this way, if the grease is not on a loaded surface it is not doing much good. I packed my lobro CV's so the balls and cages were full and no more. Nothing in the boot. Never had a problem.
Tim Dunn
Thanks for the response Tim. Im not at all handy in the machine shop but know there are several vendors selling lightened CVs. Any recommendations? Best deal? Thanks Gary
Try taylor-race.com
Ask Craig Taylor if they have a lightweight lobro for your car. If he does not have if let me know. I might be able to help.
Tim
[email]tdunn@solonmfg.com[/email]
While maching down the OD of the joint seems an easy answer, a very common mistake and reason for failure is not honing the ball travelways after the machining. The heat from cutting is enough to distort the grooves that the balls travel in and the result is binding that can't be felt by hand but will lead to pre-mature cage failure.
Craig Taylor will tell you about it.
I use stock LOBRO joints, as I never saw the advantage of helping create a failure by lightening the CV joints. I know the engineers will disagree, but it is just my opinion.
Actually, it's not the heat of machining, but stress relief of the housing that is the problem. The housing shrinks when the outer surface is machined off, binding the balls, etc. However, the effect is the same, whatever the cause.
ICP is lightening some for me now, and they will use undersized balls to restore the proper relationship between the sizes of the parts.
Balls are available from Bal-tec in California.
phone 800-205-9372, e-mail [email]info@precisionballs.com[/email] or [url="http://www.precisionballs.com"]www.precisionballs.com[/url]
They have reasonable prices for small quantities.
Hi,
How much do you lighten them? The ones you buy have material left around mounting holes and were taken down to aprox half the diameter of the mounting 5/16" bolts. One that I have have been turned to this smaller diameter over the whole width, ie the Joint only centers when all 5/16" studs are in place.
Henrik
Mine have a flange (~3-mm thick) left on both ends at the original OD's. The rest of the OD is cut down as you described.
[quote] Balls are available from Bal-tec in California.
phone 800-205-9372, e-mail [email]info@precisionballs.com[/email] or [url="http://www.precisionballs.com"]www.precisionballs.com[/url]
They have reasonable prices for small quantities.
[/quote]My 7th-grade sense of humor can't decide which comeback to post...probably better to just keep my mouth shut. ;)
HMMMMMMMMMMMMMMM.........
You need to leave the CV at its original diameter at both ends - not just for the strength, but also to locate the CV to the flange correctly, and the boot to the CV.
I usually machine to 3.200" diameter (approx halfway thru the bolt holes), and leave .10 to .125 wide ends, with a .06 to .1 radius between the cut area and the ends. This lightens the unit by about .62 pounds. More could be taken off using a 4 axis mill to profile around each raceway, but would up the cost considerably. It is also possible in many applications to shorten the body .1 - .2 inches, but care has to be exercised so as to make sure that the balls don't run too close to the edge. This usually means centering springs and buttons in the driveshaft ends - not easy to do for most guys, and probably not really worth the effort and expense.
The undersized balls are .8655 dia - about .0015" under. If you want to do this, make sure that you measure your original balls first - there are some CVs out there with different sized balls. After a couple of years useage, the original balls can be put back in.
The strength of the ball cage can be increased considerably just by using a Dremel tool with a small stone to radius all of the edges of the windows that the balls reside in. The cage is made of a high-carbon thru hardening steel, and those sharp edges are great stress risers. Radiusing the corners even just .020" will more than double the impact strength.
Richard took most of my thunder by his excellent post. We remove about .75# in the same manner that Richard describes. We then hone the ball tracks to eliminate the bind. One further trick is to temper the cages slightly, as they are through hard steel and highly sensitive to stress risers. Heat to about 550 degrees for an hour to draw them back about 5 points Rc. This helps the toughness. We always have the lightened and honed CV joints on the shelf for $99.00.
The tripod conversion is possible, but requires new tripod housings, boots, inner tripod joint, and axles. The gain is not worth the expense. If your transmission and upright stub axles have only the evenly spaced six-bolt pattern, you will either have to EDM the extra three holes, or buy the RT41 housings rather than the van diemen style. These are way too expensive.
Hope this is useful.
Craig
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