The time has arrived to put the finishing touches on our IMCA stock car, and I can hardly contain my excitement at seeing my baby come to life.
In this, the final installment of our Building an IMCA Stock Car series, we’ll install the steering system, gut and install the fenders and doors, locate and pin the hood, select and attach the front bumper, attach the plastic nose piece, and hook up the paint sprayer.
Steer You Right
When considering the steering system, I chose a KRC power steering pump and serpentine belt and pulley arrangement. Ken Roper of KRC says the Goodyear belt furnished with the system, the one with angle cuts across the belt grooves, allows pulleys to be misaligned by .100 inch, or half the thickness of a dime. Use the shims and spacers furnished to achieve this. Check it with a good straight edge.
My KRC pump came with several changeable flow valves. These valves allow a driver to select the most comfortable steering feel. The pump itself is somewhat lighter than the stock unit. The KRC pump weighs 3.2 pounds, and is even lighter than most aftermarket pumps. On these nose-heavy cars, everything helps. I opted to start with the 3.17 GPM valve, KRC part number 21312. Since the setup on this car uses so much caster, I felt we needed more power assist. Roper recommended his largest— the 9.6 cc pump—for the stock car.
“Pumping more fluid, it adds more power to the steering at low speeds such as in the pits and even in the middle of the corner when engine speed is low,” he says. “The flow control valve limits over pumping as revs increase, thus retaining driver feel.”
Lube It
In order to lubricate the stock car, I chose Admax Performance Lubricants, manufactured by Bade Inc. Bade starts with a conventional oil made from a good petroleum base stock. Company representative Tom Vosnick explained that Bade has been able to chemically bind an increased amount of high strength additives, including moly lubricants, into the oil. The additive package is the key to an oil’s ability to do its job. These additives control both the strength and lubricity of the oil.
Vosnick and I spoke at length about which viscosity of oil to use in the JR Motorsports engine. I explained the way the engine is to be used and the temperature variations here in Texas. Now, I know many local racers dump in some 20W-50 and go race. Vosnick cringed at the thought. He said this was holdover thinking from an era when 50 wt. was used because engines were loose and oils lacked a good additive package to combat the heat. He also said much more power is required to pump the heavy oil through an engine.
Vosnick recommends a 5W-30 oil for the engine. He said I could use 10W-30 if I wanted, but he thought the 5W-30 would do just fine and add a bit of power. He said the lighter oil carries the additives to where they are needed to do their job. The lighter oil, in fact, has more ability to carry heat away from hot spots in the engine. So, I chose Admax Moly Maxi Racing Oil 5W-30.
I also discussed rear gear lubricants with Vosnick. He stressed the need for something better than the discount store grade. Although we won’t be running long races, there will be considerable heat buildup with the 6:50 gears. Again, the additives and friction modifiers in the Admax lube can reduce horsepower requirements. Admax Moly Maxigear RGO #1 will be used in the 9-inch Ford floater rear.
Since we are using engine and rear gear oils from Admax, it is only natural to use their high-grade transmission oil in the Mike’s Transmissions Powerglide, Admax Maxitorque AD500-2.5.
Let’s Roll
To get the car rolling, we obtained two sets of Aero Race Wheels. Starting a new season, it makes sense to have a spare for each corner. Of course, the wheels are IMCA legal at 19 pounds and 8-inches wide. There is also a bead lock for the right rear with a mud cover held on with Deuz fasteners.
I spoke with Wayne Redmon at Aero Race Wheels. We discussed offsets and chassis setups. Redmon explained that Aero makes its own dies for forming the company’s wheels. The raised tire retaining bead is DOT legal, but still has an edge to help retain the tire.
Remember, you can’t use a bead lock on the right front. The Aero Race Wheels shell, or rim, also has more brake clearance than some others. Having more space between the wheel and the brake caliper reduces heat and pressure buildup in the tire. Redmon suggested we use an initial setup combination of 2-inch offset and 4-inch offset wheels.
“Use 2-inch offset wheels on the front, and 4-inch offsets on the rear,” he says. “With the front being wider, this will have the effect of tightening up the car. You can then adjust the car with different offsets to suit your driver’s needs.”
Sometimes it is easy to misunderstand the term “wheel offset” as it is commonly used. It’s backwards. Less offset puts the wheels farther out. More offset tucks them in closer to the car. The offset should really be called backspace. If a wheel were lying on the floor, outward side up, backspace is the measurement from the floor to the bottom of the wheel mounting surface.
Cover It Up
It is now time to cover up all the work we have done. Stock cars have fenders, doors, a hood, and a deck lid. This car will also have something to cover up its nose.
The hood and doors can be gutted out under IMCA rules. The deck, or trunk, lid cannot. Stock doors are mostly fastened to their interior bracing by a folded flap around the perimeter. Grinding around this edge will remove the flap.
Door top edges will require the persuasion of a torch or reciprocating saw. The result is a door skin. The same tools will be needed on the hood. The door skin should be located much the same as stock. Don’t overlap side sheet metal, those IMCA rules again. I drilled 1/4- inch holes through the door and the door bars. Five 1/4-inch bolts hold each door skin in place. If the doors are bolted on, they can be easily removed to hammer them straight again.
Moving to the front of the car, a fender mount must be fabricated. I used some .083 x 1 1/2 inch square tubing. If you cut it 17 inches long with 45-degree ends, it will be close. Weld to the frame horn covering the square hole. A plate about 3 inches long welded to the top will form a rest for the hood and fender.
Bolt the fender here first. Then drill through both the fender and the bottom of the window post for the second bolt. To complete the job, use a third bolt at the bottom through the fender and into the rocker panel.
The hood is a different animal. If all is not right, it can cause problems. Usually hoods are located by four pins and held down with clip pins. I have had a hood tear out, leaving the clips in place. It wasn’t my fault—the wall moved. A bent up hood probably won’t fit back in place on the pins either.
So, what is the solution? I have had good results using two pins to locate the hood and two slide-in clips at the rear. A seatbelt with its latch holds down the front. Since the hood is not rigidly attached, a crash will move it around, but doesn’t necessarily wad it up.
Before the nosepiece can be fitted, a bumper must be attached. The IMCA says to use a GEM bumper, don’t reinforce it, and narrow it if you like. I found an ‘89 Toyota 4Runner bumper which had been injured in the freeway. Cut only slightly longer than the width of the frame horns, it weighed 8 pounds. This doesn’t give much strength, or much protection, but it’s legal.
It is at this time you must determine if you are going to build a tank or a race car. The bumper mounts offer a measure of protection, as does the bar in front of the radiator. The mounts for this bumper are 1 1/2 inch x 1 1/2 inch x 1/4 inch angle-iron welded to the frame. These extend out so in the final measurement, the front edge of the bumper will be more than the required 6 inches in front of the frame horn. A 9-inch piece of 1 inch x 1/8 inch square tube is welded in the bumper. Then the bumper is clamped in place and welded.
In this car, the radiator is 18 inches behind the bumper thanks to the narrow C&R downflow unit. The bumper mounts give it some protection. Beyond that, just know you will need a radiator once in a while. I don’t want a tank, I want a race car.
Nose jobs don’t come any cheaper than this. Performance Bodies makes a variety of shapes for stock cars. It will come to you in two pieces which must be riveted or bolted together. Be sure to use washers with the rivets. I chose an early Monte Carlo nose for no particular reason other than that is the style many of these cars use. It fit perfectly, lying right on the bumper and against the fenders. I ordered a black one not knowing what color I would eventually use. Performance Bodies has primer in a spray can, which must be applied before painting the nose. In fact, use it anytime you need to paint polyproplene plastic.
With the hood, fenders, and bumper in place, hang the nosepiece over the front. The bumper location worked just right to support the nose. Next, Pop rivet the plastic nose to the fender on each side. I know it may sound bizarre, but the nose is only attached to the fenders— it is allowed to float. This floating around keeps it from getting torn easily. Plastics can be wonderful.
A Little Paint
Let me say now, I am not a paint and body man. For my race cars, I favor a 50/50 paint job. That is, at 50 feet and 50 mph, it looks real good. Stock car racing is a contact sport. These days, a gallon of automotive paint can put a scare into a hundred dollar bill. I use enamel from The Home Depot. At $18.75 a gallon, I’m happy. It shines great after I have oiled the car down with mud release. I bought a new tire for what I saved on paint.
Then there’s the Sleepy method of choosing a race car color. First, I go to a hardware or parts store and find a color I like in a spray can. After spraying a sample on a piece of metal, I take it to The Home Depot and tell them I want a gallon to match. Now, I have perfectly matching touch-up paint readily available anytime.
Now, it’s wheel scale time. I like to set up a car like it will be at the track, not at an empty weight (2,693 pounds). I loaded the car with three full five-gallon buckets of water simulating the position of the driver. This added 135 pounds. The scales showed a total weight of 2,828 pounds. The percentages read as follows: Front 52.2 percent, Rear 47.8 percent, Left 55.1 percent. A starting point for cross weight will be 52.2 percent. Most of the tracks we run are tacky early in the night, but become slick and hard by feature time.
I spoke with Jeff Anderson, a severaltime national IMCA Stock Car champion. He says he often places as much as 300 pounds of weight in the left rear of his Terminator Chassis car to get traction on these surfaces. So much for lightweight race cars. Just make sure the weight is where you want it.
I’m sure there will be some shock and spring changes as we run the car on different tracks. Roger Mealey of QA1 Shocks and I talked at length about this. He is sending me a valve kit so I can change the valving in the QA1 shocks if I want.
Currently, the QA1’s at each corner use #5 valves for both compression and extension. This is the way we will run the car the first night out. After 4 to 6 weeks of racing, I’ll bring you a follow up on how we are doing and what we have learned.
Enjoy your IMCA Stock Car. If you have questions or comments, e-mail me at sleepy.gomez@worldnet.att.com.
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