3 Signs Your Timing Chain is Broken
During timing control, the camshaft is synchronized with the crankshaft. This allows air to enter and exit the engine at precisely the right time. It also tells the engine electronics when to fire each spark plug for optimal combustion.
How a timing chain works
A timing chain is a bit like a bicycle chain. If you’ve ever ridden a bicycle, you know that the chain connects the pedals to the rear wheel. When you pedal, the torque of the pedals is transmitted through the chain to the rear wheel.
In a four-stroke engine with a timing chain, the torque from the crankshaft is transmitted through the timing chain to the camshafts. The timing chain also keeps the crankshaft and camshaft perfectly synchronized with each other. This allows the valves to open and close at exactly the right time for each piston as it moves up and down.
Symptoms of a faulty timing chain
1) Chain noises at start-up
Normally, you shouldn’t hear the timing chain when starting your car. If you hear an unusual rattling or rumbling noise from the engine at start-up that goes away after a while, you may have a faulty timing chain component.
Some vehicles have louder engine noise than others, so be cautious if any new noises appear. If you’ve had your car for years and have always had a slight rattle from the timing chain, it may not be a problem. However, it never hurts to have your vehicle checked if you’re unsure.
2) Misfiring or Rough Idling
The timing chain optimizes the combustion process by controlling the flow of air in and out of the combustion chamber. If your timing chain has skipped teeth, valves may be opening and closing when they shouldn’t. This will cause your engine to run rough, especially when idling.
3) Engine won’t start
If the timing chain breaks, the engine won’t start.
What causes timing chain noise?
Timing chain noise is often caused by a loose timing chain tensioner. The timing chain tensioner compensates for the play on one side of the timing chain. Hydraulic tensioners
These engines have an oil passage that runs through the front of the engine to a small piston. When the oil is under pressure, this piston applies pressure to the timing chain tensioner, lubricating the timing chain.
If you ignore your oil change intervals, the oil passage to this small piston can become clogged, preventing the piston from lubricating the timing chain. This will result in more chain wobble. Mechanical Tensioner
There is another type of timing chain tensioner that is mechanical rather than hydraulic. A mechanical tensioner uses a spring and pawl instead of hydraulics.
A spring applies pressure to the tensioner piston, which presses against the chain guide. A pawl then locks the tensioner. This holds the chain guide in place more permanently and securely than spring pressure alone. The engine may stall if the timing chain hits the pawl directly, or if the tensioner is slightly loose. A slightly loose tensioner may cause a faint timing chain noise for a moment on start-up.
What causes a timing chain to break?
Bad timing chain tensioner
A bad timing chain tensioner will cause the timing chain to become loose. This puts dynamic stresses on the chain when starting and stopping the engine, increasing wear beyond the chain’s design tolerances. Over time, the additional stresses can cause the timing chain to break.
Broken timing chain guide
A broken timing chain guide can cause the timing chain to move out of position. This can cause the timing chain to break if it comes into contact with another component, or the chain to come off if the timing gear moves too far out of place.
What happens if the timing chain breaks while you are driving? If the timing chain breaks while you are driving, the engine will stop and the car will stall.
It is important to note that in certain vehicles, a broken timing chain can cause severe damage to the engine. This depends on whether the motor is an interference or non-interference motor. If the valves come into contact with each other, or with the pistons and valves, engine damage can occur.