This post should have been a recap of the 2019 Midwest Muscle Car Challenge hosted by Bowler Performance Transmissions. This event is a ton of fun, hugely supported by sponsors (which means awesome door prizes and a fantastic swag bag), and all the money left over goes to a fantastic charity.
But that is not this post.
After a successful Kentucky region points event where the car, on the surface, endured 12 runs from two drivers with not a hint of complaint, I put the car on stands for inspections before the Midwest event, which included a track day at Putnam Park.
After changing the oil, the differential fluid, and the transmission fluid, I pulled off the wheels so I could inspect the suspension and flush the brake fluid. On the passenger side, I was met with a completely missing rear upper control arm bushing. It had completely melted out.
The arm was supported entirely by the front bushing. Amazingly, it wasn’t shifting much. I’m sure it moved under load, but these arms are well built. But still, this isn’t acceptable. I dismantled the suspension on the passenger side, re-wrapped the header, and added a heat shield in addition to replacing the bushing.
A few days later, I took the car to the local Cars and Coffee. It’s about a 20 mile round trip.
After returning from the trip, I pulled the passenger front tire to inspect. To my dismay, the bushing had melted again. It wasn’t completely gone, but material had melted out and was dangling from the arm. The shielding hadn’t worked well enough.
I had two options:
- Get a bushing made from steel or bronze for this location
- Replace the arms with something that had a metal bushing in this location.
I ended up trying both. John Bouchard out of Nashville heard of my plight and offered to copy my delrin bushing in metal, so I mailed him my last spare bushing so he could lathe a new one.
I also hit the UMI Performance web site and ordered a set of their racing upper control arms.
Sadly, neither made it to my house in time to install for Midwest, so my $350 entry fee was converted into a charitable donation.
But I’ll talk about the UMI arms for a bit. They’re a flat arm, so they require either a tall spindle, or tall ball joints. Otherwise they’ll hit the frame in droop too soon and you’ll start picking tires up off the ground.
They feature offset ball joint pads for more caster, and the killer feature – an adjustable rod end at the bushing location. This has restored an air gap between the header and the arm, which will dramatically reduce the temperature the arm is subjected to. And it cut the enormous stack of shims you see in first picture down to just two. I still have to get it to an aligment shop to have the alignment dialed in, but my garage alignment has me right at -2 degrees static camber, +6.5 degrees caster, and 1/16″ toe out.
Installation was straightforward. I laid the old arms and shim stacks on a piece of paper and marked the ball joint pad and the cross shaft mount locations, then put the UMI arms over the sketch and lined it all up on the bench.
Once the metal bushing arrives from John, I’ll rebuild the Speedtech arms and make them available for somebody else that needs an upgrade.
The car made it to Grossman Tuning’s Eurotrash block party yesterday, and made it home with no signs of melting or adverse behavior. The A/C even worked perfectly on this 90 degree day.
Upcoming events for me:
- May 26-26 KYSCCA Drivers school, nightcross, and Points Event 2 – Kentucky Fair and Exposition Center
- June 1-2: Optima Search For the Ultimate Street Car, Round 3 – NCM Motorsports Park