How To Identify A Burnt Valve

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How To Identify A Burnt Valve
How To Identify A Burnt Valve

Video: How To Identify A Burnt Valve

Video: Engine burnt valve symptoms 2022, December

During the operation of a car, a situation often arises when its engine suddenly starts to work intermittently, twitching or, as they say, "troit". There may be several reasons for this, and one of them is valve burnout.

How to identify a burnt valve
How to identify a burnt valve


Step 1

To determine the exact cause and determine which valve has burned out, do the following.

- Start the engine at idle speed.

- Warm up the engine for a few minutes.

- Open the hood.

- Remove the cap from the spark plug of the first cylinder. If the engine speed has changed (slowed down), this cylinder works.

- Put the cap back on and remove the cap from the spark plug of the second cylinder. Repeat the previous step for all cylinders.

- Check the functionality of all cylinders, determine inoperative. If the engine speed does not change when the cap is removed from the plug, this cylinder does not work. There may be several reasons for this.

Step 2

The first reason is a non-working candle. Unscrew the plug and replace it with a new one (it is better to replace the entire set). Start the engine. If the engine works the same way as before, the candle has nothing to do with it. If the engine stopped tripping, the problem was eliminated and it was precisely in the inoperative spark plug.

Step 3

The second reason is the absence of a spark on the candle, i.e. malfunction of wires or distributor. To check for a spark, unscrew the spark plug from the idle cylinder, put the cap on it and place it on the engine. Crank the engine with a starter. If there is a spark, then the electrician and the distributor have nothing to do with it. If there is no spark, check the valve, valve cover, cams, high voltage wires and wire caps.

Step 4

If the ignition system is in good working order, there are two reasons that the engine troit: it is either a burnout of the valve, or destruction of the piston (breakage of rings, sticking of piston rings, destruction of the piston baffles). Start the engine and let it run. When doing this, observe the breather. Then stop the engine, remove the idle cylinder plug and inspect it. If the candle is dry and clean, the valve is burnt out. In this case, air or light smoke will come out of the breather.

Step 5

If the candle is filled with oil, and thick smoke comes out of the breather, then this means that the problem is in the piston: the rings are stuck or destroyed, or the piston itself is damaged. Having made such a check, you can be 99% sure of the reason why the engine is troit, and find out which of the valves has burned out.

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