Chapter 203 August 2012
SCRATCHER REPAIR AND UPGRADES
So Neil (www.thinkfastengineering.com) was in town to measure Scratcher and he came at a good time. I had just cracked the chassis tab where the upper control arm mount goes into the frame upright and he got to see it and engineer a solution. We are going with a replacement frame upright for the rear of the front upper control arm mount and it will be a thicker steel and it will be 4130 where the old one was mild. Steel was ordered and new sliders were too. While Neil took all the measurements to analyze Scratcher's geometry and work with me to go faster, he also got to see an auto-cross car that we were doing some setup work to and made some comments on that as well.
So the upright pieces arrived with new slider tabs and I got busy cutting out the old ones and smoothing out the areas where it connects to the frame and then cutting the new uprights to fit juuuust barely. I had to tap them in with a hammer and I kept all the gaps to an absolute minimum. I had to take of less than I thought I would and it went surprisingly fast. Powerful grinders and various air tools made this a pretty easy job. I got incredibly lucky that Louis Gigliotti had time and didn't mind making a house call to TiG up the new parts. Saved me a TON from having to load up and go across town and unload. HUGE THANKS LOUIS. Louis has built a lot of chassis that have passed tech with GA/TA/ALMS so I knew Scratcher was in good hands. I cleaned out the area to work in, put blankets down to work from (concrete is hard and I'm old!) and made sure everything was out of the way.
Above: New rear upright tapped into place and Louis warming up his stitching skills and spark-box on a 4130 piece of scrap. Neil said the front uprights could stay as they don't see near the load and they are braced by the motor plate.
Why yes...yes I do have a little 'fish-eye' lens for my iPhone!
Below is the finished product. Since I'm running the chassis ever lower and lower Neil is concerned about the roll center in the front and so with an upper slider AND a lower slider I can run a long bolt with spacers and adjust the height of the inboard mounts of the UCAs and play with roll center and also eliminate any anti-dive due to rake.