66 Nova SS Project

[byndbad914]

Mocked up the left upper A and the lower A pieces. Coleman made the lowers, I asked for 12.5" with the rod end fully closed on the jam nut and damned if they didn't nail it perfect! They think of ever'thing too, the shock mount has a floating bushing so no matter what rmonoball the shock would have it would work, with a nominal width of 0.625" which is exactly what pretty much every 1/2" heim I have ever seen is They knocked the price down a bit too and let me source my own heim which I prefer as I use the really nice HD ones as the liners last longer than a "typical" heim from McMaster-Carr and the like and then got the high-angle spacers and joints from Kartek in SoCal as I have bought from them for some time now and they have always been good to me. The same heims are slightly cheaper at Summit tho' so they are a good source I will use as well.

In the pic it is hard to tell but at 12.5" locked in I should have around 0 to -0.5 deg of camber which is a perfect starting point. If I were only expecting it to be a race car I would have made the minimum -.5 to -1.0 deg but there should be enough adjustment in the control arm heim to get out to -3.0 deg if I need to. With radials, -3.5 is not that uncommon if you are able to push the car hard enough (V8 Supercar guys would laugh at -3.5 deg and tell me to learn to drive) and I can get there if I suck the upper A arm in a little as well so I should have more than plenty of adjustability.

The lower monoball joint pin has shims in .125/.250/.375/.500 to adjust roll center. I will set the car up with .625 on each side and go from there. The upper ball joint ball/pin piece can be swapped out as well to adjust roll center, so again, tons of adjustability. Technically I could adjust ride height within that .625" lower range as well having the upper ball joint adjustable as well if I want to tweak overall stance/height.

The lower caster arm I simply ordered the shortest swage tubing they had in 3/4" thread size (9") and I need to cut it down to around 7" - I machined some 1" thread nuts to the 1" diam tubing so I can splice with it and have something to get a wrench onto when locking the jam nuts - the knurled section isn't all that great and if you pipe wrench it they just get all scratch up.

The uppers are from Speedway and I had them put in angled upper BJ mounts to ensure max compressive travel and unfortunately the threads were honked up on the right side, so they are going to send me a new upper and jam nut, should get them tomorrow. The left one went together without a hitch.

So I have some stuff to work with this weekend at least and keep the ball rolling. And before the peanut gallery gets after me, the grade 5 hardware is what I had laying around - I will be getting all grade 8 stuff

[Payton King]

Looking forward to the progress. I see you are using the C6 spindle, will you make our own steering arm or used the one cast in?

[byndbad914]

I will use the one cast in and then make the rack able to move back and forth to adjust Ackermann and have a slip joint in the steering rod from the steering column. Pretty slick too as, for the fronts, the arm is angled down to offset the caster, meaning that when the steering arm is perfectly level, the spindle appears to be at about 7 degrees caster, so that will make resetting caster at the track easy if I futz with camber and so forth.

I will drill them straight and get rid of the damn taper on those, use a thru bolt and a standard rod end, and then I can machine spacers to set bumpsteer based on where final rack placement is.

The rears point rearward, so I can set those at 14 deg if I want to be particular and keep everything lined up like the front - technically you don't need caster in the rear but some is good as it supposedly keeps everything loaded and not at a zero point where every little bit of clearance in ball joints is then wandering around.

[Flash68]

Very impressive Tim. Hurry up and finish it.

[byndbad914]

so this item is actually what I considered the largest hurdle of the whole project, so I am just glad to have it in hand and done. Everything else is busy work, but getting the drivetrain figured out was going to be the tough part.

I machined the adapter on the lathe at work - engineers don't usually get to use the tools but having a little machining background from my mechanic days bought me some favor Then I bored the center out to the dimensions Andrew at Mark Williams asked me to hit and took it to him for final splining. They had to rent a special shaper to cut this specific, odd-ball Hemi spline that Mendeola uses but it all worked out bitchin'. Heat treated it to boot - this should be the strongest piece in the whole drivetrain haha.

The batteries died right after I took these so as I feared, the images are a bit blurry (happens every time right before the batts die). Nonetheless, close enough for internet work. The assembly in the aluminum housing is the tail end of a C5 Automatic torque tube - we took it apart so I could machine the driveshaft side a bit and also replace the bearings, which I need to get on order. Basically I will be making a large adapter piece to bolt to the bell on the Mendy that then holds that C5 tail assy and the new adapter piece inline with the input shaft of the trans. This will be a tedious item to make but not difficult.

You will note I have a piece of sheared off input shaft for test fitting - they sent this to me for clutch alignment so it came in handy for making the part v. schlepping that trans over to Mark Williams for fitment.

[byndbad914]

spent some time on the lathe at work this evening and turned out four press-fit plugs to replace the stock UBJs in the C6 uprights with a tapered ream. Now I can use Howe race UBJs that are fully rebuildable and I can get different lengths on them to adjust roll center.

Now I just need to update dimensions in my CAD model and determine what upper A length I need now and where the mount holes need to be in the car for correct geometry...

[byndbad914]

Here is a shot of my dual A assy as of today - all the numbers are exactly what I want in terms of roll center, camber gain, and overall adjustability. I now have to fully adjustable pivot points (top and bottom) that I can mess with ride height and roll center pretty much at will.

For the front I am starting with a 13.5" lower arm length, 10.5" nominal upper length, and what both calculated in my computer and was verified with my angle finder in the attached image is a parallel lower arm nets me an 11 deg upper angle for a static RC of ~2.5" which is what I was shooting for. The lower pivot is not a ball joint but monoball from Coleman and they make a set of spacers that come with it. I can swap those around to vary the upper A angle and therefore static RC but comes with a 1:1 change in ride height (move the pin up 1/4" and the car drops 1/4") so if I need to make a big change I can then just buy a longer or shorter upper ball joint insert.

I then went on to verify I could easily get -3.5deg neg camber on the front for radials. A few may note I underestimated the arm lengths I would need upon my original parts purchase (might notice some of the heims adjusted nearly all the way out) so I will be getting longer pieces on their way next week. All the upper needs is some longer tubes, the lower I just need a new tube for the caster but will need a new custom lower made as they make those to order. Not a big deal, just a few bucks blown in the process of figuring out where I am going with the car