The NASCAR-sanctioned Late Model stock car we have been reporting on for some time is now finished. In the latter weeks of April, we completed assembly, aligned, and set up the car, and took it to Orlando Speedworld for a shakedown run. The car performed better than expected. Here is how we prepared the car for testing.

The very first thing we always tell you to do is to measure your moment center location and redesign it if needed. So that is exactly what we did with our LMSC. We ended up making minor changes to the arm angles by changing out the offset slugs in the upper mounts.

The upper control arm mounts from Hess Race Cars provided us with plenty of adjustment opportunities. The slugged mounting bracket allowed us to fine-tune the moment center location as well as set the antidive amounts.

After the changes, the MC was located at 2.636 inches high and 0.560 inch left of centerline at static, and moved to 1.710 inches high and 3.307 inches right of centerline. This location is good for this car with a higher center of gravity than the Late Model touring cars. The camber change on the right front was minimal, and we ended up with about 1 degree of positive camber at the left front after dive and roll. The actual tire temperatures will tell us if the cambers are correct.

We set up the centerline of the car using the framerails. This is a perimeter car, which means that the frame and suspension are equal on each side with no offsets allowed. We measured the distance from the bottom sidewall of each right-side tire to the centerline and adjusted the Panhard bar so that the right-side tire contact patches were lined up and parallel to the centerline. We did this before attempting to square the rear end because lateral movement of the rear end to line up the right sides will affect the rear alignment relative to the centerline.

We used the common 3-4-5 triangle method to create a line that was perpendicular to the centerline for rear square measurements. Once we had the marks on masking tape, we pulled a string over the marks and held the string with lead ballast.

Next, we dropped a plumb bob off the axle tube near the ends and measured back to a line that ran perpendicular to the centerline we had previously established. Project mechanics Kenny Hellyer (in hat) and Mark Jones take careful readings on tape. We adjusted the rear trailing arm (truck arms on this car) eccentric so that the rear end was exactly 90 degrees to the centerline.

Before we did our front-end adjustments, we locked the steering shaft with two vise-grip pliers (8th image). We centered the steering box, locked the shaft, and then did our bumpsteer check. Then we aligned the wheels to straight-ahead and set the toe. With this type of power steering, if the box is not centered, the power steering will always try to seek the center and pull on the wheel even when the wheels are pointed straight-ahead.

This adjustable, Coleman Racing-supplied front link replaces the shock for positioning the spindle for moment center measurements and bumpsteer checking. The rod is easily turned to adjust the height of the spindle to its relative position when at ride height (9th image). We need the spindle, along with the control arm angles, to be positioned correctly when the car is raised and supported on jackstands. In this case, for moment center measurements, the car was raised exactly 10 inches. This makes subtracting the height offset easy.

The next step was to adjust the front-end settings and check the bumpsteer. Kenny turns the adjuster while Mark reads the dials (page 2, 1st image). This Hess chassis was well designed, but we found that the slug in the right side of the drag link was installed upside down. Once we inverted that, the bumpsteer was perfect. The left side was installed correctly, and that, too, was perfect (within less than 10 thousandths of steering movement in 3 inches of travel).

We then checked Ackermann by stringing the tires out in front of the car 10 feet. We made a mark with the wheels straight-ahead and then a second mark for each wheel with the wheels turned about the same as they would be in the turns. We had less than 11/48 inch difference in the two sets of marks, which amounts to 0.029 inch, or about 11/432 inch, of added toe when the car is in the middle of the turns. That is minimal and acceptable for our purpose.

The right-rear fender posed a clearance problem when we moved the right-rear tire out to align it with the front tire. The body was hung with the rear end misaligned. So we had to use the common baseball bat method of creating a fender flare. It worked great. At the track, the tire never rubbed the fender.

Once we warmed up the engine and checked for any obvious fluid leaks, Dalton prepared to take the first hot laps. I had already taken the car out to bed the brake pads. Using a method described in the last issue, I ran at moderate speed and applied light braking for six cycles with a 10-second period between each cycle. Then I increased speed to do six more cycles at medium braking pressure with the same 10-second gap between cycles. Then I went faster and did six hard braking cycles with the gaps in between, followed by a few laps of cool down with no brakes and a complete cool down in the pits

While getting the brakes ready, I got a chance to feel the car at close-to-maximum midturn speeds on the last cycles and it felt very neutral in handling. Once Dalton was able to get it up to full speed, we would have a better idea of how balanced it was.

As Dalton straps on his belts and HANS Device, we need to thank Butler Built seats for providing the modern seat with the latest in head-and-shoulder supports. Safe-Quip supplied the seatbelts. The cockpit was a bit cramped for Dalton and I, as we are both over 6 feet tall, but there was sufficient room. He insists on using a three-layer driving suit, quality fireproof gloves and shoes, and a new racing-rated helmet.

The float levels had to be adjusted on our C&S Holley carburetor. After a little fooling around with fuel delivery and jetting (5th image), our acceleration smoothed out, and we were able to get up to full speed.

The car was found to be very neutral, once we discovered that the right-rear tire was going flat on the initial run and corrected that. In Turns 1 and 2, he ran the bottom on every lap. We ran short and long runs, and the car stayed neutral and consistent. Dalton has run his ASA South series car here, and we were a full 400 pounds heavier than that car and still only a half-second off his ASA car's times. I think we are going to be very competitive. For the race, we can lose 100 pounds by virtue of running a crate motor.

Below, we see the car running through Turns 3 and 4 with the same results. The left-side tires are on the stripe. The blacker surface (tire marks) on the left is the wide apron at OSW, where just the day before a TV crew was shooting drifting scenes for the series Hogan Knows Best with the Hulkster in attendance.

All in all, we were very satisfied with the results of this project. The next step is to take the car to North Carolina and Tri-County Motor Speedway for a practice session and a race on Friday night. Then, it is on to Hickory Motor Speedway for a Saturday night race. We'll let you know how that goes. Stay tuned.

We want to thank the following companies who helped make our project NASCAR Late Model Stock Car possible. Without their generous support, we could not have accomplished all of this. The project has provided us with a lot of valuable information to use for our tech articles as well as a means to put into action all of the advice we have offered over the years. We will continue to race and test this car on tracks in North Carolina, South Carolina, Tennessee, and Virginia. We will keep you up-to-date on all the developments as they happen.

SOURCE
Longacre Racing
14269 N.E. 200th St.,
Woodinville
WA  98072
4-25/-485-0620
www.longacreracing.com
F.A.S.T. Racing Products (Cooling System)
Dalton Zehr Racing WILWOOD ENGINEERING
4700 Calle Bolero, Dept. SC
Camarillo, CA 93012
C&R RACING
286-A Gasoline Alley
Indianapolis
IN  46222
3-17/-241-0774
www.crracing.com
Chuck Gafrarar - Body Installation
Sign Post Decals Five Star Stock Car Bodies
Hyperco (Springs) Performance Distributors
Memphis
TN
9-01/-396-5783
performancedistributors.com
David Ryland - Professional Painter Coleman Racing
Dept. SCR11
Menominee
MI  49858
MSD Ignition
El Paso
TX
9-15/-857-5200
msdignition.com
Braille Auto Batteries
QA1 (Shocks) Safe-Quip
803-732-0937
www.safe-quip.com
C&S Specialties
www.candsspecialties.com
SPAL
Bart Wheels Eibach Springs
17817 Gillette Ave.
Irvine
CA  92614
959-752-6700
www.eibach.com
Tiger Rear Ends
7-04/-636-7029
www.tigerrearend.com
Hess Race Cars
ATL Fuel Cell GM Performance Parts
www.gmperformanceparts.com
Butler Built Motorsports Equipment
70 Pitts School Rd. N.W.
Harrisburg
NC  28027
7-04/-784-1027
www.butlerbuilt.net
  • «
  • |
  • 1
  • |
  • 2
  • |
  • View Full Article