Shocks must be mounted so...
Shocks must be mounted so that there is no binding or interference with any suspension parts or the chassis. This is a common problem and causes handling problems. This is an extreme case, but again, not all that uncommon. This stocker class car had two front shocks that were bad from rubbing on the springs. The top mounting hole had to be relocated to center the shock in the spring.
It doesn't take much of a bend in a belt to cause it to de-pulley and come off. The solution is to inspect the alignment of the belts on all pulleys on the engine. Use a straight edge and lay it against one pulley to see how that one lines up to other pulleys. Don't necessarily trust your eyes because often the problem lies out of your eyesight.
6.Broken Throttle Parts
Loss of throttle is a common cause of a race car loosing power abruptly. The throttle shaft can shear off, the connecting bolt can break or loosen or the linkage can just fatigue and break somewhere between the gas pedal and the carburetor. This is another area where we seldom do proper inspection and don't discover there is a problem until we have a failure.
Breakage is not an acceptable way to schedule maintenance. Each moving part in the car needs to be inspected often. Put this item on your maintenance sheet and make sure someone goes over every part of the throttle linkage system.
This dirt modified uses a...
This dirt modified uses a coilover eliminator device for mounting the spring on the trailing arm. Care should be taken to maintain this unit. If it's allowed to corrode, it will seize and ruin your setup. Even a restricted movement can alter the handling a great deal.
Properly attached and adjusted pedal stops can help prevent stress on the throttle linkage and carburetor shaft. It's not a good idea to use the carb throttle stop as a pedal stop. An overzealous driver can apply way too much pedal pressure and twist the shaft off. Take time to adjust the linkage so that you will be applying full throttle (butterflies wide open with maximum pedal throw), but not stretching and stressing the linkage.
7. Shocks Bottoming Out Or Over Extended
A radically errant setup can often be traced to a mechanical binding problem. Often, we find that a shock is either bottoming out from excess travel or hanging in rebound from too short a useable travel due to improper mounting.
Once you have finished building your car and have established the ride heights, measure how far each shock's shaft extends into the shock body. If you know the length of travel of the shock, you can subtract and know how much rebound, or compression, travel you will have available.
There are a multitude of Heim...
There are a multitude of Heim joints and similar components that need to work freely in order for the car to handle the way we predict. One tight joint can significantly alter the way the car reacts to the dynamic forces and can make the job of driving it a nightmare. For dirt cars, this maintenance might need to be conducted on a weekly basis.
Problem areas are with the left rear in rebound, the right rear in compression, and the right and left front in compression. On entry, the right front compresses which then causes the LR to go into rebound. If the LR shock becomes fully extended, then a lot of load will be transferred off the LR corner and you will loose grip in that tire making the car loose in.
If the RF shock becomes fully compressed, that corner will be effectively locked up stiff and the RF tire will lose grip. Coming off the corner, the RR corner will experience a lot of travel and the shock will compress up to four inches depending on the setup. Make sure you have enough shock travel available so that there is no chance that the shock will bottom out.
8. Suspension Binding
Another source of mechanical binding lies in the use of sliders in some cars. The various designs of coilover eliminators and big spring sliders need constant maintenance. Follow the manufacturer's recommendations and inspect these units often. They will bind up and stick if not properly maintained, especially on dirt cars.
The shock mounts are under...
The shock mounts are under a lot of stress and loads on a circle track car. We need to be sure that the design is adequate to withstand these loads. The welds must be inspected often and we need to make sure the shock is not contacting the chassis. This car has a support brace that is mounted very near to the spring mount and will provide rigidity to prevent stressing the chassis tubing.
With all race cars, and especially the dirt cars, we need to break down and inspect all moving parts in the chassis on a schedule that makes sense. When we wash the car after a race, the water tends to collect in the various parts that handle chassis movement. A good car can slowly go to bad without proper maintenance.
The parts we are talking about include the upper and lower control arm pivots and ball joints, the wheel bearings, the rear trailing arm connecting links, steering components, throttle linkages, sway bar links, and all other connecting points that may corrode or seize from lack of lubrication.
Most race teams that ignore this important task will experience a car that slowly fails to respond to chassis setup changes. This is a clue that maybe you need to look at beginning a maintenance schedule ASAP.