anyone know the taper on C6 Vette ball joints?

[David Pozzi]

Originally Posted by byndbad914

yeah, it is like the roof on our houses, they're called out in pitch, not angles, but in the case of ball joints everyone talks angles.

and the thot plickens... I found some Viper stuff on the Howe site that is 1.69"/ft taper which is almost exactly 8 deg - which is also exactly the angle I calculated my upper ball joint on the Vette spindle to be. Not 7, not 10, but 8 degrees.

So maybe the Vette and Viper are both running this funky taper. WTF? Being a mech engineer I deal with stupid crap like this on a regular basis - someone reinventing the wheel - I would love to hear the excuse why the standard 7 or 10 degrees is not quite right but 8 is perfect Apparently I missed the class at school that discussed the finer points found in children's books such as porridge temps and mattress firmness. Must have to have a PhD to get exposure to that kind of knowledge.

Chevy Corvette - built in America... using metric fasteners and other nonstandard items. Wouldn't surprise me one bit if taper was based on millimeters; man enters store, walks up to counter, 14mm over 100mm reamer prease!

edit - took a break, stepped back from the tree to see the forest, and thought this thru a bit here. I think I have a simple plan to circumvent the funky taper stuff for my project. I can run a Coleman lower control arm with a monoball lower and standard Chrysler K727 1.5"/ft taper, ream the spindle lower to this taper (as this will not open up the bottom diameter which is good), then press out the C6 upper and make an adapter to fit in it for the same 1.5/ft taper, run a Speedway upper A arm assy which takes a standard K772 ball joint which I can get variations from Howe and others. The only "custom" part is the adapter for the spindle upper and reaming which is all pretty cake to redo if I mess up a corner. Whacka$$ taper should then be circumvented. Now to let this simmer a bit and make sure I didn't miss something

How about upper ball joint to wheel clearance?

[byndbad914]

good call on that - I am going to have to be careful how much stud sticks out of the upper to make sure it doesn't scrape the wheel. The 18s are so freakin' big I feel pretty confident but thanks for bringing it to the foreground of my mind again.

[preston]

So the UBJ will go down into the top of the C6 upright like a normal arrangement or are you talking about mounting the UCA under the upright and pointing the UBJ upside down up into the upright ?

Either way of course your pivot point will change from C6 geometry but I'm sure you were totally aware of that.

[mfain]

http://www.victorypp.com/inventory/37

Not necessarily a recommendation - just an observation. Victory Performance (and I'm sure others) offer "ball joint ring taps". Any thoughts on tapping the upper end of the spindle for a screw-in ball joint? A good idea for aluminum? That might help control the height above the spindle that the ball joint sticks up. At one time I had also considered machining the upper spindle for a press in sleeve (with shoulder) that accepts a screw-in ball joint. A secondary machining operation could cut a recess into which you could "sink" the flange, also allowing you to lower the ball joint into the top of the spindle. Pressing in such an adapter ring would probably be a more precise operation than trying to press in a ball joint.

Pappy

[byndbad914]

Preston - short answer = yes, I am going to have the UBJ upside down. It does indeed change stock geom by lowering the pivot point, but since I am building a custom frame and pickup points for the Nova I will put the upper A pickup points at the correct height to have the roll center and camber gain that I want.

Pappy - I considered what you are talking about - getting the factory UBJ out of the spindle first to see what the material looks like after that procedure but being unsure if I could get good threads in afterward I decided to go the route I am. I also am not sure of what alloy that spindle is, tho' I admit to not doing any sort of search to figure that out but that would be important to know if you wanted to tap it as well. Another thing I considered was making a threaded collar (or buying if the OD fit in the existing hole), knurling it, pressing it into the upper, and having a good, steel thread interface to put a BJ into.

There are certainly multiple ways to skin this cat I believe so it is just a matter of picking one and just doing it. I do like the idea you have about using the stock upper if the taper does fit as well as you state after reaming.

Dave - double checked and in the 18" wheel I have over 1.75" of clearance above the spindle "ear" so I will have plenty of room to fit the lock nut in over the stud. Actually I had checked this on my Corvette but it has 19" fronts factory so after your post I realized I forgot to remove 1/2" for that so my stomach churned a bit but I remembered there was a fair amount of space

[byndbad914]

Originally Posted by mfain

http://www.victorypp.com/inventory/37

Not necessarily a recommendation - just an observation. Victory Performance (and I'm sure others) offer "ball joint ring taps". Any thoughts on tapping the upper end of the spindle for a screw-in ball joint? A good idea for aluminum?
Pappy

I got the uppers out of the spindles yesterday after borrowing a tool from AutoZone. It will be easy to make a piece to press back in with the reamed taper for the Howe UBJs I have. I got rather lucky, in my scrap alum I had a machined cylindrical piece that I jacked up making and have almost thrown out numerous times - it was exactly the right size to fit around the UBJ and shorter than the piece in the tool kit or the tool would not have fit

That said, in regards to questioning if you could tap the upper, I can say it might be possible but a total PITA to figure out how to do. The Howe upper I have will not slip into the existing hole so it would have to be opened up a bit. Then tapped. That strikes me as a pretty tough item to get square; probably have to build a jig to bolt down to a table on a vertical mill just to get it set up for machining. Furthermore, the material is rather thin around the existing BJ and the overall thickness there is pretty short so getting threads in there and more than just a few strikes me as a bad idea.