When a driver is granted a club racing license s/he is issued a vehicle log book. One important purpose of the log book is to record the vehicle's compliance with technical and safety standards at each event as judged by the Club Racing Technical Steward. Major safety issues (e.g., loose ball joints) need to be dealt with before a car is allowed on the track or else. Minor issues (e.g., improper window net fastening) may be noted in the log book and must be addressed before the next event.

The technical and safety form used by Club Racing Stewards is attached. It gives you an idea of the areas which are inspected. In addition, the National Tech Steward issues technical bulletins covering areas of special concern. Three areas have been noted which require attention: metal fatigue, ball joint failure, and trailing arm mounting pad failure. Another area of concern is the condition of wheels used for track events. Finally, brake rotors can fail especially when used with performance pads. We'll look at each of these areas in more detail later.

Whether you're a racer or a driving school participant you should be concerned that the car you put on the track is in a safe condition for the stresses it experiences there. Do everything you can to make sure your Bimmer provides you with tons of fun and worry free miles while you are at an event and then on the drive home. That's one important reason the BMW CC insists that your car be inspected before each track event. BMWs are the ultimate driving machines which respond especially well to TLC, and not just the kind that a chamois and Zymol provide. Don't just wax it, wrench it too.

I follow the inspection procedures recommended by the club and then some. I'm personally present when my car is inspected. My mechanic and I are especially careful about the suspension and brakes. As some of you know, I suffered a catastrophic loss of steering at an event some years ago that was most likely caused by failure of a lower control arm not replaced soon enough. Now, not only do I inspect all the suspension components for wear and the nuts and bolts for looseness, I replace key parts (e.g., lower control arms, end links, stainless steel brake lines, tie rods, bushings, etc) about every two years before signs that they may become unsafe. I use OEM parts, including new nuts and bolts, and install them following recommended procedures, especially where torque values are concerned.

Because I race my car and use a track suspension, mounting points on the unibody and elsewhere are subject to extraordinary stresses. I've reinforced all the sway bar mounting points and end link attachments. We've beefed up the front subframe and even so we've found some mini cracks in it between events when we go hunting for them with a mirror. (For a good kit and excellent instructions for repairs see: http://www.turnermotorsport.com/catalog/suspension.htm).

Yes, I'm pretty careful. I've learned that the motto "An ounce of prevention is worth a pound of cure" applies to me. Those of us who race or who have radically modified our cars for track use need to be especially careful about vehicle maintenance. For the rest, following BMW recommended maintenance procedures , adhering to BMW CC inspection requirements, and being aware of what to look for will keep your Ultimate Driving Machine safely roaring around the track for a long time.

BMW CCA CLUB RACING TECHNICAL AND SAFETY INSPECTION FORM

Event: ________________________________
Date: ____________________
Eng Size: _________________cc
Entrant: ______________________________
Model: ___________________
Year: ____________________
Driver: _______________________________
Chapter: ____________________________________________
Car #: ______________
Class: ___________
Color: ____________________
Log Book #: _______________
Weight: _____________

ALL ITEMS MUST BE MARKED INDIVIDUALLY WHERE APPLICABLE

To be completed by authorized BMW CCA scrutineers and for the use of the club. Completion in no way relieves the participant of responsibility for the condition, level of preparation, and safety of the vehicle.

COMMENTS:

Approved for competition:

________________________ Scrutineer

_____________________ Chief Scrutineer

Sticker issued: ______________ Date

Metal fatigue (Issued by: Jeff Penley, National Chief Scrutineer)

WARNING! Investigation into several racing incidents in the 1996 Club Racing series indicates a serious safety issue for all racers: metal fatigue.

The areas of concern in this bulletin are primarily the stub axle and front hub of older BMWs (pre-1983).

It is strongly recommended that the rear axle stub shafts and the front wheel spindles undergo "magnaflux" testing on an annual basis. This will involve removing the parts from the car and taking the thoroughly cleaned parts to a qualified laboratory or metal shop for testing. Costs for the testing should be approximately $100 for all parts. Magnaflux testing a non-invasive procedure, utilizing magnetic dust and infrared light to identify stress fractures and fatigue in metal components.

At this time it is STRONGLY recommended that every car built prior to 1983 be checked by a qualified metal testing facility. However, should failure of these parts in BMW CCA Club Racing become a recurring problem, proof of certified inspection will be required for competition. This is for entrants safety as well as the safety of other competitors. It is not our intent to cause you to incur additional expenses needlessly.

Other potential trouble areas that need to be monitored on a regular basis by a careful visual inspection include:

• the joints and mounting areas on front and rear subframes (looking through the sides of the flat plate in the center of the front subframe)
• differential mounting points
• motor mount brackets
• and any load bearing stamped metal parts

Ball Joint Failure (Issued By: Michael Yaskin, National Chief Scrutineer)

Investigation into several Club Racing/Drivers School incidents during the 1997 season have revealed total failure of the Ball Joint Stud on the Lower Control Arm resulting in immediate loss of steering.

We recommend the following preventive measures (until otherwise noted):

1. When preparing an E30 for club racing, start with new control arms.
2. Replace all steel control arms after 2 seasons of use or 20 events.
3. Replace all aluminum control arms after 2 seasons.
4. Replace control arm if a ball joint has any amount of "up and down" play when squeezed with a large "water pump" pliers.
5. Replace control arm if a ball joint has any "side to side" play in it when grasping the outside of tire and shaking from side to side or up and down.
6. Do not re-use poly lock nuts.
7. Torque ball joint stud nuts to spec!
8. Re-torque nut several times during season. It shouldn't turn--if it does, investigate why.
9. If an "incident" involving enough force to bend a road wheel occurs--replace control arm.
10. When trailering a car, do not tie car down around or thru control arms.
11. Use quality replacement parts. BMW original or Lemforder brand are the only ones we recommend. There are inferior quality control arms being sold by large, well known suppliers.
12. It is important to understand that the type of failure we have seen may be undetectable by in car physical inspection. Change the arms at the time and usage specifications listed above, not just with normal ball joint wear inspection.

Inspect the subframe tapered socket and area around the socket for cracks and elongation--use a mirror to see the upper portion (especially on the right side of car--we have seen many cars that crack in this area). This may cause ball joint failure.

PART NUMBERS FOR E30 LOWER CONTROL ARMS

Aluminum $244

• 31 12 1 130 823 left
• 31 12 1 130 824 right

Steel $115

• 31 12 1 127 725 left
• 31 12 1 127 726 right

TORQUE SPECIFICATIONS

Outer--control arm to spring strut with new poly stop nut 47 ft lbs, 65 nm
Inner--control arm to front axle carrier 61 ft lbs, 85 nm

To show that "hand or wrench tight" is not appropriate--here are a few more torque specs (notice the big difference in ft lbs)

Brake bleeder valves--all 7mm wrench size 3.5 ft lbs
Brake bleeder valves--all 9mm wrench size 4.3 ft lbs
Front wheel hub collar nut E28, E24, E30 M3 210 ft lbs

BMW has a handy pocket sized torque spec book available:

Supplement 13-- part # 01619783691 $12.75
Binder-- part # 01699099704 $ 5.59
Registers divider--part # 01699099705 $ 2.40

E36 M3 Trailing Arm Mounting Pad Failures (Issued By: Michael Yaskin, National Chief Scrutineer)

Upon inspection of several E36 M3 race cars we have found the trailing arm mounting plate, also called the toe adjuster plate mounting pad, to have FAILED. The plate is fastened to the body with three 18 mm head bolts, the bolts thread into a threaded tube, the tube is tack welded in two or three spots around the outer circumference to the body , these welds crack and then PULL OUT OF THE BODY.

We recommend at minimum the following preventive measure be taken. A good, solid, 360 degree weld on all six tube inserts should provide sufficient reinforcement. This must be done by a skilled welder with mig or preferably tig welding equipment. It should be noted this is much easier to repair as a preventive measure than after the pad tears out of the body.

Wheels Used For Track Events (Used by permission of the Tire Rack: http://www.tirerack.com/wheels/frames/wheeltech_f.html)

For real driving enthusiasts there aren't many feelings that equal the excitement of running laps on a race track at their vehicles' limit. And while race tracks were once only accessible to race prepared cars, today many car clubs and professional driving schools allow drivers to learn more about high performance driving as they run their street cars (with relatively few modifications) on the same tracks as their racing heroes. For that matter it is not unusual to have more track time (enough to drive several hundred track miles per day) at a typical club event or driver's school than most actual race weekends. And while it's common sense that track use will increase the wear on a car's tires, brakes and shocks, there are less obvious critical components which also wear out ...like its wheels! Yes, wheels do wear out...or better stated, they fatigue.

Because wheels are so critical to the driver's safety, top racing teams visually inspect their wheels at the track, monitor the total number of hours they are used, and crack test them on a periodic basis. Any wheel that shows signs of fatigue or age is discarded and replaced. For that matter Indy Car sanctioning bodies require that their race participants' wheels meet strict standards when new and that previously used wheels be recertified before every 500 mile race.

Unfortunately the same rigorous wheel inspection procedures are not typical for many driving enthusiasts who use their vehicles on the track. Maybe it's because wheels are so trouble free that they are often overlooked! But if let go for too long, wheels that are subjected to high stress track conditions can fail.

When it comes to wheel fatigue it is important to remember that it is caused by a combination of the frequency and magnitude of the stresses it encounters. While small stresses can be accommodated for thousands of cycles...large stresses accelerate the wheel's fatigue factor and the number of fatigue-free cycles is significantly reduced. So what is it about track use that reduces the life expectancy of wheels? Lets explore some of the important factors:

All wheels flex as they are driven through a corner. In normal street driving the amount of flex is minimal. However since today's DOT legal competition tires almost match the performance of yesterday's racing tires, every corner that is taken at the limit on the track causes significantly more flex. It's the combination of the extra tire grip and the resulting extra flex that fatigues wheels faster when used on the track. And don't forget that spins, running over the track edge curbs and unintentional trips through the run off areas add their own unique extra stresses.

During track use, wheels will often reach temperatures never encountered on the street as they help dissipate the brake heat. This constant cycling between the ambient temperature and the extremes encountered on the track can increase the fatigue rate of alloy wheels.

In normal street driving wheels are typically removed from the vehicle only when the tires are being rotated (typically every 5,000 miles) or replaced (typically every 25,000 to 40,000 miles). But when used on the track wheels are typically removed from the vehicle at the start and finish of each day, as well as, anytime the vehicle's brakes or suspension are being serviced. Additionally DOT legal competition tires wear out and are replaced much more frequently than normal street tires. These extra tire mountings and vehicle installations can increase wheel fatigue as they wear out the wheel's lug seats and the vehicle's lug nuts/studs or lug bolts/hubs.

So what should track drivers do to take better care of their wheels and minimize the possibility of wheel failure? Before going on the track:

Make certain that the wheel's installation hardware is correct for the vehicle and in good condition. Since almost all of today's cars are designed with hub centric wheels which transfer the vehicle's load from the center of the wheel to the car's hub (and allow the lug nuts/bolts to just hold the wheel against the hub), it is important that track wheels continue to be hub centric to help distribute the forces encountered on the track. If an aftermarket wheel requires special centering rings to properly fit it to the hub, be sure they are installed and installed correctly.

When any non-original equipment wheel or lug nut/bolt is used on the vehicle it is important that there is sufficient thread engagement between the lug nuts/bolts and the vehicle's hub. Its acceptable to increase the thread engagement by installing longer wheel studs in the hubs after verifying that the lug nuts don't bottom out on the studs. However if the vehicle uses lug bolts they must maintain as close to the original amount of thread engagement as possible. Longer lug bolts may cause interference with the parking brake or other components inside the hub.

Always torque the wheel's lug nuts/bolts to the hub using a "star" pattern until the vehicle's correct torque value is reached.

NOTE: If wheel spacers which are thicker than the height of the hub are used, they also need to be wheel and hub centric to help distribute forces.

After coming off of the track:

At the end of every track day the wheels should be allowed to cool, cleaned front and back, and inspected for minute cracks, impact damage and runout. At the first sign of a crack appearing (regardless of size or location) or an indication the wheel has been bent it should be removed from service and replaced with a good wheel.

Every time new tires are mounted, each wheel should be inspected to verify that it is round and true. If it is found to be bent, it should be removed from service and replaced with a good wheel.

If the wheel has been used for an extended period of time you may want to have a local machine shop professionally crack test it in the off season before considering subjecting it to another year of track use.

Wheels are a critical component to your car. However because they tend to fatigue slowly, periodic inspection will usually reveal the signs of aging and use (such as minute cracks in the wheels spokes or near the bolt holes) long before they can become a serious problem. However if overlooked, once a crack has formed it will concentrate the stresses in the weak area and allow the crack to spread until the wheel fails.

It is important to note that track use and/or participation in racing voids the manufacturers' warranties of all street wheels.

Rotors

We've come a long way since the days when Ferrodo and Metalmaster were considered the brake pads to have for driving school and track use. The latest generation of high tech brake pads made by Performance Friction, Pagid, Hawk, Porterfield, Powr Pad, etc. are made of exotic carbon kevlar or carbon metallic composition. Their ability to withstand heat and stop vehicles is remarkable. So too is their price.

One price you have to pay for using these modern marvels of braking technology is rotor wear. Modern pads may wear out rotors before the pads themselves are worn. Make sure your rotors never wear below the manufacturer's recommended thickness. Inspect them carefully for uneven wear or warpage. Use ducting to help bring fresh air to the rotors. Use high performance brake fluid (e.g., ATE Super Blue/Gold, Motul, Castrol, etc.) to prevent boil over. Change the fluid frequently if you frequently track the car. Bleed the brakes even more frequently. Read the manufacturer's recommendations concerning pad break in and whether the use of slotting or cross drilling of rotors is recommended.

Because of the high heat these pads generate, an especially important consideration is metal fatigue apparent as minute hairline cracks to the iron surface of the rotors. These fine, spider-web cracks are only visible by close inspection with the wheel removed and a strong light shone on the rotor surface. There's no problem when theses minute cracks stay towards the center of the rotor surface. But once these cracks migrate towards the outer edge of the rotor, watch out. This is when the rotor becomes subject to shattering under braking, a catastrophic failure if there ever was one.

You may have heard something about cryogenic freezing as a way to prolong rotor life. Apparently, this trick was discovered by the NASCAR boys a few years back. I've heard that it is especially effective at reducing the rotor cracking caused by performance pads. If the cost of replacement rotors is especially high this may be worth your consideration. If rotors are not expensive, then just change them whenever these cracks make the rotors unsafe.