Things to Know About Subaru Engine Timing Belts & Chains - information from the the pros at Shingle Springs Subaru serving Sacramento, CA

In order to synchronize all its moving parts, modern car engines have sophisticated timing systems. The timing system physically links the movement of the engine's valves with the pistons so it runs smoothly and efficiently at all speeds. Some such systems use a rubber belt to keep everything working in perfect harmony, and it's one of the most crucial parts of any such engine! In certain engines, a failure of the timing belt can even lead to severe engine damage. Find out below the answers to some of the most common timing belt questions.

Timing Belt Adjustment

4. Which Subaru Models Have Timing Belts?

Commonly found on most Subaru vehicles built in the 1990s and early 2000s, the EJ family of engines all feature timing belts. But, in 2010, the new FB family of engines featured an all-new design including a timing chain. Check your owner's manual or look under the hood to find out which engine your Subaru vehicle is equipped with -- or, just give us a call! Our service technicians can look up your car by its VIN and find out which engine it was equipped with from the factory.

Uninstalled Timing Belt

3. What Are The Advantages Of A Timing Chain?

The earliest engine timing system used a simple set of gears and sprockets. But, as engines got larger and more complex, overhead cam designs moved the camshafts further away from the crankshaft. A huge crankshaft gear meshing with the camshaft gears just isn't practical. Instead, manufacturers developed timing chains and timing belts.

Metal timing chains are heavier and often louder than timing belts -- however, they won't require as much maintenance as the engine's oil system keeps the whole timing system lubricated and protected from wear and tear. Most engine timing chains are designed to last the entire lifetime of the engine. By contrast, a timing belt is a much simpler, lighter weight system which can allow for better performance. However, since the timing belt is made of rubber, it's a wearable part that will need to be replaced at regular intervals.

  

2. What Maintenance Does My Vehicle's Timing System Require

While most Subaru models moved to a permanent timing chain, if your Subaru still has a timing belt, you'll want to check your owner's manual or maintenance schedule to find out how often it needs to be replaced. For example, the 2009 Subaru Impreza owner's manual recommends timing system inspections every 30,000 miles and having the timing belt replaced every 105,000 miles.

Failure to change the timing belt on time could lead to a timing system failure. In most Subaru engines built before 1995, this will cause the engine to stall but probably won't do much harm. But if your Subaru was built after 1995, it's probably equipped with an interference engine. In an interference engine, the valves and pistons will occupy the same space in the top of the cylinder at different times in the engine's cycle. If the timing system fails, pistons are likely to strike open valves as the valvetrain and crankshaft come out of sync -- leading to severe engine damage that can cost thousands to repair! To prevent this, just have the timing system inspected regularly by a trained Subaru technician.

Timing Belt Removal

1. What Are The Symptoms Of Poor Engine Timing?

If the timing of your engine is off by enough, the engine may not even start. But if it's only subtly off, your engine may run poorly and may need an adjustment to the timing system to restore correct performance. Symptoms include sluggish acceleration and poor fuel economy. You might also hear "engine knock," a pinging or ticking sound that develops when gasoline combusts at the improper time in the engine's cycle. The engine may even backfire, when gasoline combusts in the engine's intake or exhaust instead of the cylinders.

If you suddenly experience these symptoms, head to Shingle Springs Subaru for a timing system inspection. A worn out timing belt or chain may have simply "jumped" a few teeth on the gear, causing the engine to come slightly out of sync.