9. Broken Shock Mounts
The bolts that connect the...
The bolts that connect the control arms and other suspension components should be checked often for tightness. Should a front lower mount become loose, the moment center location will change, the bumpsteer will change and the bolt will be stressed to the point of failure. It's a good idea to tack weld washers over the slotted holes in the position where you want your control arm to be mounted. If the bolt loosens, at least the arm angle will remain the same. Check these and other bolts for tightness often.
The mounts that hold your shocks on the car take a lot of abuse in all forms of circle track racing, especially with the coilover types of suspension designs. One of the worst failures you will encounter is a broken shock mount. This can't be fixed during a race.
The way the shock mount is attached to the car can be an indication of trouble. Each mount should be strong enough and supported adequately so that the loads the mount will experience will be distributed without stressing the joints.
Regular inspection of the metal around the mounts can often show the start of a crack or stressed area so that we can re-weld or replace the mount. This exercise can greatly reduce the chance that you will lose a shock mount during a race.
10. Loose Bolts
The suspension parts endure a lot of force from braking to acceleration. The control arms at the front and the ends of the rear links can become loose as the bolts are pushed and stretched lap after lap. If these loosen during a race, the car will become un-driveable.
Many circle track cars use...
Many circle track cars use aluminum axle housing tubes because they are lighter. They also have a greater chance of bending and so the rear wheels need to be checked more often for unwanted toe. You can do a very accurate alignment check on your rearend with strings. Once the rear has been aligned, measure from the front of the axle tubes to specified chassis points so that rechecking the rearend square is quick and easy at the track. A simple rear wheel toe and camber check will tell you if the rear axle housing is bent.
If your car is doing strange things, one of the first and easiest things to check is for a loose bolt in the suspension system. Even if the joint is fairly tight, but not real tight, it can slip and result in a rearend that is out of alignment, a serious problem nonetheless.
If you find a loose, or "not-so-tight" bolt in your suspension system, think about realigning the car as soon as possible and definitely before the next outing. Educate your team members to this so that they can make the team aware when they are "nut and bolting" the car. Merely tightening the bolt does not necessarily fix the problem
11. Bent Axle Tubes
Rear wheel alignment is so important to how the car will perform that we should be aware when things might go south in that department. Incidents happen in the course of racing and testing that could cause the rearend axle tubes to become bent.
The bend could be in any direction to affect toe, camber, or both. A set of rear wheels that are toed either in or out excessively can cause the rearend to lose grip all of the way around the track. Sometimes the cause can go unnoticed.
Common causes are a brush with the wall or contact with another car. When either of these happens, make sure to check the toe and camber at the rear wheels. We often concentrate on front wheel toe and camber settings and forget that rear wheel geometry is just as important.
12. Plumbing Problems
How you plumb your car for cooling the water or oil can be a problem. There are some common misconceptions about these two that can cause overheating and/or engine failure. Here are a couple of common mistakes teams make.
When plumbing your water lines, remember to install a proper sized pulley on the water pump so that the speed will not be too slow or fast. It is a general rule of thumb to match the pump pulley size to the crank pulley size.
You might also need to install a restrictor in the radiator at the point where the water enters the motor at the nipple. There are several sizes available to regulate the flow rate to more efficiently allow the water to cool.
In plumbing a dry sump system, always place the filter where it will be the last thing the oil passes through before entering the motor. If not, lots of unpleasant things can happen. New oil coolers often have slag and other pieces left inside that come loose and flow into the motor if not filtered out. Placing the filter before the cooler could be a problem.
Flow the oil through the radiator oil cooler into the bottom and out the top. This pushes any air that may be trapped in the unit out to prevent cavitations. Use hose ends that are the free-flow design, where the bend is made with tubing and not an abrupt 90-degree turn drilled into a solid aluminum block.