By Chuck Johnson
Speaking of doing it right, every time we build a racecar we learn something new. It’s the small details that make a difference. This time we learned about spot weld drill bits, which allow you to drill out the weld without drilling a hole through the body. In the past, we used to remove unneeded brackets by drilling out their spot welds. The problem with this is the car ends up looking like Swiss cheese later on. This might not harm a car functionally in road racing, but when you race on a dirt lakebed like El Mirage, it’s critical that every hole in the car is sealed to prevent the driver’s compartment from filling up with dust and blinding the driver mid run. This might sound strange, but it happens in land speed racing.
In general, the SCTA rulebook can be described as straight forward in some areas, yet ambiguously complex in others. When it comes down to it, the rulebook is up for interpretation just like any race series. However, it’s important to realize up front that it’s only the chief tech inspector’s interpretation of the rules that counts at the end of the day. To avoid any disputes when the car was finally built and ready to race, we made sure to keep Steve Davies, the SCTA chief tech inspector, in the loop during the construction of our roll cage.
With the cage construction complete, we then turned to painting the cage and interior. Painting is all about good prep work and an investment up front will go a long way towards ensuring that your paint job will look good in the end. The first step is to mask any areas that you don’t want painted. Aluminum foil works great for quickly covering tricky things like pedals, wiring, and brake lines. It also helps to lay masking paper on the floor boards to keep the over spray from settling on the floor board while the cage and other areas are painted. If excessive over spray builds up on a surface it makes it difficult to get a smooth paint job down the road.
After the masking is complete, the next step is to degrease the surface. This is especially true for the roll cage as steel tubing usually has an oily layer on it to give it some corrosion resistance. MEK does a great job of breaking down the oil and grease. If you live in a state full of hippies like we do here in California, MEK can be pretty hard to find. As a substitute, denatured alcohol will work nicely.
We degreased the cage surface with denatured alcohol and then roughed up the surface with sand paper and scotch brite. For good measure, we then degreased one more time before we laid down the first coat of primer. On the bare metal surfaces of the cage, we used self etching primer which will help prevent rust down the road.
We ended up spraying the whole interior with primer, but it’s really not necessary. In fact, it’s an unecessary pain in the ass. To save some time and money, just scuff the factory paint with some sand paper, degrease, and then paint it. Simple as that.
After the primer was dry, we blew off the painted surfaces with compressed air to knock off some of the loose overspray that had built up in the interior. We had to sand down the more persistent, rough areas of overspray with fine sand paper before applying the top coat.
Once we laid down the primer coat, we began applying the top coat, working from the roof to the floorboard. When selecting a paint for a top coat, its best to choose a hi-gloss paint that is easy to clean and easy to touch up. Also, think about driver comfort when selecting the color. A lighter color will reflect heat and ultimately lower cabin temperatures whereas a dark interior color like black can make life a bit more uncomfortable for the driver. The most common colors we”ve seen used for a racecar interior are gloss white and battleship grey. We decided to be a bit different this time around and chose a matt silver for our interior. We like the color, but hope it cleans up as easy as a high gloss paint.
With the cage build complete, we’ll next turn our focus to prepping the suspension with some trick KW coilovers and SPL links. Stay tuned for the next installment of Project Land Speed Racer 240SX!