Truckers News : February 2009
Big Rig Basics
M any of the most complex repair operations on a heavy truck are simple and can be accomplished eas-ily by a do-it-yourself technician he or she acquires the right knowledge first. One of the best examples is setting overheads, a job likely to cost you $150 or more at a dealer. Many ace mechanics are afraid to do this job in this age of increasingly sophisticated engines. Yet anyone who has turned some wrenches and knows a bit about how an engine works, given certain specifics, could easily do the job flawlessly. True, if done wrong, you could end up with an engine that would not even start and ruined injectors or overhead parts. But do it right and you'll have an engine that will perform better, run more quietly and guarantee maximum valve and injector life. The biggest difference between success and failure is a simple chart of engine crankshaft and valve positions you need to turn the engine prior to setting each injector or valve. You also need to know how to set the height of the injector and the valve clearances properly. Also, with any typical do-it-yourself job, like replacing a water pump, it's important to use a torque wrench to tighten the fasteners, or you could end up with a leak. But a torque wrench is completely useless without knowing the factory torque recommendation for each bolt or screw. Such sophisticated mechanical operations are never covered in your owner's manual. That's why it's so important to obtain the factory repair manuals or service bulletins when you want to do work beyond oil and filter changes. Getting started You can get basic maintenance information for nearly every truck and major component. Most of the engine, truck and components manufacturers offer manuals either in print or on CD-ROM via their websites. Some offer continuously updated maintenance information in a format that is read off the OEM's website in an interactive format displayed on your computer screen. International's Brian Mulshine, manager of service development and marketing, says the EPA requires the manu-facturers to offer such information to truck owners because proper maintenance often reduces emissions. But Mulshine argues that there is so much going on in a mod-ern truck that it's neither practical nor cost-effective to do all the work yourself. For example, if you take the truck into an Interna-tional dealer for even a minor job, they are likely to update, or flash, the programming in your engine ECM. A change recently flashed in cycles each fuel injector just before engine shutdown in a way that prevents the needle valve from sticking down the road and may greatly extend the life of an injector. International also offers software for diagnostic purposes. 28 TRUCKERS NEWS FEBRUARY 2009 When a do-it-yourself repair fails, the cause often is not having the right reference materials By John Baxter BIG RIG BASICS Reference Materials Information Underload?