Sales are all about timing having the right parts at the right time for the right job.
Take timing component kits, for example. Component kits are available for most timing belt system replacement applications, and having them in stock is a good way to make sure your sales efforts and your customers needs are synchronized. A survey of technicians showed that they are more likely to perform a complete timing belt system replacement when application specific components are available as a kit, reducing the chance for mismatched parts.
That’s an important point because timing belts can have one of several different teeth profiles in addition to different lengths and widths. If there's a mismatch between the belt and drive sprockets, tensioner or idler pulleys, it will ruin the belt. With a kit, you and your customer know that all the components will work together perfectly.
Tensioner bearings are “sealed for life” and are not serviceable, so there's no way to clean, inspect or re-lubricate the bearings when a timing belt is changed. On many newer engines, spring-loaded automatic tensioners are used to keep the timing belt tight. If the slide plate is worn or sticking, or the spring is weak, it can prevent the tensioner from maintaining proper pressure. Some vehicles use a hydraulic tensioner that is pressurized by oil pressure. If it leaks, it could destroy the belt. Always advise your customer to inspect for leaks around the plunger and shaft. It's difficult to determine the true condition of the tensioner components when they are not running under a load. Consequently, a simple visual inspection may miss tensioner bearings that are on the verge of failure. Kits make replacement of these components easy.
Finally, replacing the tensioner and idler pulleys along with the belts will restore the timing belt drive to like-new condition and significantly reduce the risk of future problems another reason why kits are a good idea. Many technicians don't replace these components then wonder why the new belt they installed failed a few thousand miles later.
For the parts store, component kits make a lot of sense because of the lower number of SKUs required for coverage. Greater availability in the aftermarket draws attention from technicians, who often demand same-day delivery.
When a customer is installing a timing chain and gear set on a pushrod engine, the new crank sprocket usually goes on first, followed by the cam sprocket with the chain on it. If the tech doesn’t follow the correct procedure, he can damage the chain or gears. With OHC timing belts, the belt is usually slipped over the pulleys, then tightened. If somebody tries to stretch a rubber belt to get it over a pulley, they can easily damage the belt.
A common installation error that's made when installing any type of timing kit is misaligning the timing marks. Timing marks on the crank and cam sprockets must be properly aligned. Methods for aligning timing marks can vary so the installer should always refer to a shop manual for the exact procedure if he is not familiar with the engine. This is especially true on engines with balance shafts, which can be tricky to time correctly. Misalignment problems can also occur if the cam sprocket is installed backwards, the wrong thickness of washer is used (incorrect end play), a thrust button is forgotten, or the crank sprocket is not positioned properly on its keyway. This type of misalignment can cause rapid chain and sprocket wear or interference problems.
When somebody is installing sprockets on the cam and crank, they should never hammer directly on the sprockets or chain. Both sprockets should be pressed on evenly, keeping them parallel. This prevents stretching or damaging the chain or sprockets.
On some applications, a separate spacer behind the cam sprocket is used to control end thrust. Replacement sprockets for some of these applications have the spacer built onto the backside of the sprocket, which means the old spacer should not be reused.