Our discussion of driveshafts includes a presentation of tracking for parts usage and life
In our previous articles on the racing driveshaft, Driveshaft 101 (Dec. '07) we examined the environment that the driveshaft operates in and the materials and components from which a driveshaft is built. In Driveshaft 102 (Jan. '08), we discussed the basics of measuring the driveshaft and inspecting it for damage.
Now let's discuss the concept of driveshaft management and how we can apply Formula 1 and NASCAR team parts management techniques to your race car to prevent failures on a $5 budget. We'll look at why the racing driveshaft needs regular replacement, how NASCAR teams manage their driveshaft needs and how you can use their methods to improve the reliability of your race car and win more often on Saturday night.
The driveshaft in your pick-up truck is designed to give many years of dependable service on the street. The street driveshaft is constructed of robust thick tubing and is capable of handling occasional massive loads at low shaft speeds. But most of its life is spent with little stress just going to the grocery store. It's unlikely to ever need full replacement.
Modern race teams use sophisticated software to track the life of parts used on the race c
If it needs servicing, typically only after 100,000 miles of hard use over a period of 10 years, it will start making noises that will eventually get your attention. At worst, if it eventually fails, you will probably just have a long walk home.
The driveshaft in your race car is also built to give dependable service in its normal application, but its design criteria are entirely different. The racing driveshaft is constructed of thin wall tubing and each component is carefully selected for light weight. This combination of features is better for smooth and efficient high-speed operation.
The racing driveshaft requires regular inspection and routine replacement because it spends its life constantly at high loads and high speeds. Catastrophic failure of the racing driveshaft will result in a wrecked race car and possibly serious driver injury or death.
When most of these situations occur, the result is called a driveshaft emergency or 911. Regardless of the reason, the need for a replacement driveshaft is normally evident just before the team has to leave for the next session, race, test, or appearance and pandemonium ensues until the problem is resolved. If two or more of these situations occur in a week, even the best teams can be brought to their knees.
Hand entry of Life-ing data can be time consuming, but very useful and critical for many p
At its basic function, the driveshaft is a simple connector linking the transmission to the rearend. But without one in place, the car slows dramatically. The strongest engine or the trickest suspension setup will not overcome a driveshaft problem. Any vibration that the driver feels will sap his confidence and reduce him to just driving around, hoping he can stop before it blows up and he crashes. He becomes totally non-competitive and wimpy. So driveshaft management is an important part of driver management that every team must plan for.
At the professional level, a multi-car NASCAR team will compete each week with two to four transporters in the garage area at the track carrying primary and back-up cars for each car number. Each of those cars will arrive complete with a driveshaft installed. Additional driveshafts will be carried on each transporter as spare parts and there may be an extra shaft stowed on each team's pit crash cart for in-race emergencies. The total number of driveshafts on-site on race day numbers in the hundreds.
But most of those driveshafts will be of different lengths with specific slip yokes to suit each team's engineering combination. A team must plan to have enough of its specific shafts on-site to overcome any problems. The trackside parts truck or the local parts store will not have a suitable replacement. Missing a race because some one forgot to load enough spare driveshafts is not an option.
The process of Life-ing parts starts with communication. The team must develop good commun
In earlier years, each car was uniquely configured for a specific track type (i.e., speedway, intermediate, short track, road course) and driveshafts were specifically fitted for each chassis and kept with that car. As the teams grew to have dozens of cars, this system became expensive and unmanageable.
Now, with the transition to the Car of Today (COT), most teams have settled down to one or two combinations and more effort has been focused on individual driveshaft inspection and replacement. Each team's driveshaft combination is a closely held secret because the details can tell the opposition many things about the parts selection, chassis configuration, and tuning philosophies.
Driveshaft inventory management is the responsibility of a team's gear room. Each major team has dedicated gear room staff who prepare, service and coordinate the drivetrain systems for each car for each event. They maintain extensive usage records on each component, called "life-ing," so that individual parts with high mileage can be identified and removed from service before they cause a failure.
After each race, the used cars are disassembled and the drivetrain components are returned to the gear room for inspection. As driveshafts gradually accumulate mileage throughout their projected life, they are specifically designated for use in other less critical events like testing or show cars. Ultimately, when they have reached a pre-determined limit, they are rebuilt, sold, or discarded. No one ever earns a bonus for getting the last 50 miles of use out of a driveshaft before it fails.
In addition to tracking the life of a part, periodic visual inspections should be observed
At the Formula 1 level of professional motorsports, with teams constantly traveling worldwide, the parts life-ing and parts inventory management function is highly automated with elaborate computer programs, bar coding scanners and even radio frequency identification (RFID) scanners and chips. Every time each car turns a wheel, the mileage simultaneously accrues in the data record for each part being tracked on that car.
Parts location is an important element of these systems to determine if a specific part is currently installed on a primary or back-up car, somewhere on-site in a shipping container or halfway around the world back home in the shop. This operational information is continually updated by wireless links back to the factory.
The F1 parts management and life-ing programs are programmed to highlight specific parts that are approaching certain thresholds of use so that they can be scheduled for replacement, re-assigned to lower priority use or inspected more often. The parts supervisors back at the factory can see the locations and life remaining of all the replacement parts and select the best ones available to be in the right position to be used when scheduled. If new parts are needed, production orders are issued in real time to keep up with the team's needs. Massive resources of computers, communications, and personnel are required to maintain the system.
This computer technology is beginning to trickle down to the NASCAR teams, but the parts management and life-ing activity here is still done by paper record keeping and memory. The enormous number of cars and parts per NASCAR team make complete parts life-ing impractical. Most parts are considered expendable and retired from service due to crash damage before they reach their ultimate projected life. All replacement cars would be built with all new parts.
The arrival of the COT program and the current tight economic situation has changed the thinking of many teams on parts management. Each time a COT chassis is damaged or crashed, it's now often preferable to build a new chassis to better meet NASCAR's precise templates and incorporate the latest engineering updates. All of the used parts from the damaged car are transferred to the new chassis or recycled to become spare parts for other cars.
For high-stress parts such as the U-joints, regular replacement can prevent sudden failure
If there's any doubt of a parts age or quality, it is discarded. Replacement parts have become more complicated and expensive and production lead times have become longer. Anticipating what parts will need to be replaced has become a necessity. Dedicating team resources to parts management and life-ing is now considered very worthwhile in improving reliability and controlling costs.
A small team can learn from this professional approach and adapt these techniques to its simpler needs. Establishing a parts life-ing system in any team requires designating a conscientious crewmember as the parts life-ing coordinator. He or she must be willing to spend a few minutes each day to update the records and make them available for analysis.
This person should be a full-time worker who will be responsible for developing a logical numbering system, marking the appropriate parts and recording the parts changes as they are reported by other crewmembers. Each team member needs to understand why this process is important and help the coordinator keep the data accurate by calling out individual part changes as they are made. Having one person monitoring parts life-ing will help identify components that need inspection or are due to fail.
The most powerful tool in your pit box is the ubiquitous Sharpie. In the hands of your driver, it can make children smile and turn scrap into treasures. But, in the hands of your parts life-ing coordinator, it can give each part on the car a unique ID. The concept of unique ID is the fundamental principle of parts life-ing, because we want to track each part as it's installed, used, and removed so that we can assign its mileage to its record.
Many of the professional teams will keep an inventory of drive shafts that will be correct
A unique ID can be as simple as "Part #12" or as complicated as a street car's VIN number with each digit representing specific information in coded form. The unique ID can be written, stamped, engraved, etched, or attached to the part. All that matters is that the marking is legible, hard to deface and it will survive in the environment of heat and solvents it will encounter.
A parts record can be as simple as an index card for each part, a small computer spreadsheet or as elaborate as an expensive software system. As we saw in Driveshaft 102, some teams just write each mileage directly on the driveshaft. The size of your team and capabilities of your crew will determine what is best for you. Start with a simple card system and then expand it as your needs grow into a loose-leaf notebook or a spreadsheet.
If you tried to record all the mileage you drove in your street car in a month, it would be a tedious task to make dozens of entries. But your race car and its parts may only be used once a week in several short sessions and your crew chief is probably already keeping a lap chart of every mile run.
The life-ing coordinator needs to be alert to any changes of the components he is monitoring. When a change occurs, he simply needs to note when the change was made and the unique ID of the old and new part. At the end of the event, he can review the crew chief's practice and lap charts and determine the appropriate mileage to assign to each part's record.
At its simplest, you can monitor a chassis, an engine, a transmission, or a driveshaft. The racing driveshaft is a great example for learning this process because it has high initial value, a reasonable projectable service life and dire consequences if it fails. Once you get the rhythm of the activity, your life-ing system can grow to monitor any parts that have a predictable service or replacement life.
Fuel pumps, alternators, quick-change gears, axles and driveshafts are all critical components that seem to fail suddenly and unexpectedly. Preventing any one of these failures is reason enough to implement this system. Parts like spark plugs, brake pads, and tires are replaced regularly anyway and don't need to be documented.
Each part, be it a driveshaft or other part, must be labeled as to the installation date,
Establishing projected service life is something you are already doing routinely. All we need to do now is write the projections down and believe in them. Ask your suppliers, friends, and competitors for their advice. Inquire about any failures you see at the track and ask how old the part was. There aren't any right or wrong answers. The more information you gather, the clearer the guidelines will become.
The best time to implement your parts management life-ing system is now! The initial budget will be about $5 for Sharpies and index cards. A life-ing system that is several weeks behind current activities is worthless. A simple well-kept system for even one part can prevent disaster on a Saturday night. It's frustrating to fail a part once and drop out of a race. But it's maddening to fail the same part twice because you know you should have replaced it more often.
Ideally, if you just built a new car with all new components, the process will be easy and the records will be very accurate. For a used car, just estimate the current mileage for each part as best as you can from your memory and lap charts and start from there.
Conclusion Whether you implement a parts management and life-ing system just to monitor your driveshafts or expand it to cover other critical components, you will be taking a positive step toward preventing failures, overcoming aggravations, and smoothing the path to Victory Lane. This will be the best $5 you ever spent on your DSS (Decal Support System). And when you do win and your driver does that long smoky burn-out, please get your driveshaft checked afterwards. Driveshafts hate burn-outs!
Racing driveshafts are ordered for the following reasons:
* A new car is being built and needs a shaft fitted.
* The Crew Chief decided to move the engine back because no one is checking.
* The current shaft caused a vibration on the chassis dyno and must be replaced.
* The current shaft has been damaged in a crash and must be replaced.
* The Tech Guy checked and said to move the engine forward to where it belongs.
* The current shaft broke in the race and it and most of the car had to be replaced.
* The New Guy jacked the car up without looking where the jack pad was hitting.
The Best Reason Is:
* An active shaft has reached the end of its projected life and should be replaced.
Let's review the simple steps to establishing a parts life-ing system:
* Determine which parts are to be monitored
* Mark each part with a unique ID
* Create a data record for each part's ID
* Record accumulated mileage for each car as it is used
* Note any parts changes relative to when they occurred during prep or the event
* Update each part's data record regularly with its recorded mileage
* Establish maintenance or replacement intervals based on remaining life
* Identify and service or replace parts that are due to fail