How Does a Timing Chain Work?

Your timing chain is absolutely essential to the operation of your vehicle. If it breaks, your car isn’t going to go anywhere, and you could end up with engine damage. So, how does the timing chain work, and what happens if it fails?

The basics

All piston engines have a crankshaft and a camshaft. The pistons move up and down, and the crankshaft delivers power from them and changes that power to a rotating motion. Then, the crankshaft drives the camshaft by means of a chain. At the other end of the crankshaft is the transmission, which is responsible for powering your wheels. The camshaft opens and closes the intake and exhaust valves. For each of the engine’s cylinders, the camshaft opens the intake valve, letting in a mixture of air and fuel. Then it opens the exhaust valve so that the burned fuel gases can be released. The valves have to be opened and closed at just the right time. This process is known as camshaft timing, or valve timing.

Timing methods

There are two ways to achieve valve timing. The first is the two gear method, and it’s the most reliable. A crankshaft gear simply meshes with a camshaft gear. These gears hardly ever fail, and are usually good for the life of the engine. This is the method used in most types of heavy equipment and big trucks. It’s also used in some cars.

The timing chain method is more common with cars, especially those of a certain age. Most modern vehicles are equipped with timing belts, although some still have timing chains. The timing chain can stretch, and that affects performance. Also, some vehicles have plastic camshaft sprockets, and if they overheat they can melt. Then the chain skips, and the engine stops. If the piston comes up at the same time as a valve fully opens, the valve could bend, and the engine could even be ruined.

Identifying a bad timing chain

You’ll usually notice some signs before you end up with a broken timing chain. The most common tip-off is a rattling noise coming from the front of your engine, particularly if it’s idling. Plastic chunks in the oil are another indication that a timing chain replacement might be warranted. If you find plastic in your oil following an oil change, the cam sprocket is likely ready to fail. When this happens, these chunks can end up in the screen of the oil pump, causing your car to lose oil pressure. And once the pressure gets too low, timing chain failure is pretty much inevitable.

The last thing you want is for your timing chain to fail, because it can cause a great deal of damage to the engine, sometimes even destroying it. So make sure that your timing chain is in good repair, listen and look for hints that all might not be as it should be, and have your mechanic replace it if necessary.


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Richard

13 years of experience
601 reviews
Richard
13 years of experience
Chrysler Sebring - Strut Assembly Replacement (Rear) - Henderson, Nevada
Excellent customer service!
Chevrolet Tahoe - Alternator - North Las Vegas, Nevada
Fast and informative....Highly recommend to others

Honorio

19 years of experience
828 reviews
Honorio
19 years of experience
Acura RDX - 75 Point Safety Inspection - Palo Alto, California
Honorio went above and beyond my expectations. He was honest about which repairs needed to be done even though my service revision decreased his income. Will absolutely use again!!!! Thank you!
Honda Accord - Brake Pads Replacement (Front) - Santa Clara, California
Thank you for providing a great service at reasonable price and honest recommendations! Jesus loves to work hard and always ready to help. I had some questions after the service and I called him. He responded immediately and provided all the information.

Pete

16 years of experience
192 reviews
Pete
16 years of experience
Chevrolet Malibu - Timing Chain Replacement - San Diego, California
Pete called ahead of time letting us know upfront that there might be more damage and that he couldn't guarantee that this would fix my problem but I opted to try anyways. He showed up right on time and finished the job an hour early. And he did a great job. My car is by no means in perfect condition (my fault, not his) but at least he got it up and running for me and that's all I can ask for at the moment. I would definitely use YourMechanic and Pete again.

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18 years of experience
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Ben
18 years of experience
Chevrolet Classic - Timing Chain - Denver, Colorado
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