Everything You Need To Know About Timing Chain
Most modern cars are equipped with timing chain and are supposed to be almost maintenance free when compared to a less durable timing belt which are prone to break over the time. Timing chain relies on a set of components to function properly. So what are the other supporting component?
1) Inlet Cam Sprocket
2) Outlet Cam Sprocket
3) Timing Chain
4) Guide Rail (Top)
5) Guide Rail (Bottom)
6) Timing Gear (or it is called Sprocket Gear)
The weakest link in this network of components would be the guide rails. This is because the rails are made of plastic and may become brittle and break over time. Some diesel engines would have rubber coated metal guide rails. Most cars would come with a plastic guide rail because it is supposed to "guide" the metal chain in a correct motion. If it is made of metal, it would grind against the metal chain; and we know what happens when metal touches metal. The plastic rail would also cause less complication compared to a metal rail when it breaks and falls into the oil pan.
So, how long can the timing chain last? A good guideline would be 100,000 miles which translate to 160,000 km.
So how do you detect a potential timing chain system failure?
1) It'll be difficult to start the engine (it takes longer time than usual to crank it)
2) The engine produces a squeaky sound (Don't mistaken this with the belt sound) .
3) The engine produces a rattling sound (Due to the loose chain).
4) Cam sensor error (When the timing jumps).
5) The engine vibrates badly (similar behavior as misfiring).
So what happens when the timing chain breaks?
1) The engine's timing will be messed up resulting in piston and valve collision.
2) Engine stops running. This can only be rectified with a very expensive general overhaul.
3) If the car is driven fast when the chain breaks, the engine block may crack. Again, this would be very expensive to fix as it results in a total engine replacement.
Best practice for preventive maintenance
1) Check your timing system every 100000KM.
2) The inspection should include:
a. timing guide rail
b. timing marking
c. chain condition
e. Timing gear teeth
Who can set and installed timing chain?
1) Qualified workshop that are familiar with the engine
2) Qualified workshop with proper tools to run the job
3) Qualified workshop with proper timing set tool for the specific engine
4) Qualified workshop with guideline and SOP that uses exact torque settings to make sure the timing is set properly to prevent slips.