What is adjust the valve clearance all about?
Your engine is a perfectly timed machine that relies on many components working in harmony. The engine valves are one of the primary components of this operation. The valves are placed at the top of the cylinders, and open to allow the fuel mixture to enter the cylinder chamber, and then close to help create compression. The valves are opened by cams or rocker arms on the camshaft, which push the valve’s tappet, which forces the valve to open. If the clearance between the valve stem and the cam or rocker arm isn’t perfect, the valve will open and close at the wrong time, or may not close all the way. Adjusting the valve clearance will resolve this issue.
Keep in mind:
- If your vehicle has hydraulic tappets, then the valve clearance will adjust automatically.
- When the valve clearance is adjusted, the entire valve and camshaft system should be inspected.
How it's done:
- Remove valve covers
- Check valve adjustment
- Adjust if needed
- Install new gaskets
- Reinstall valve covers
Your valve clearance should be inspected anytime that your camshaft or cylinders are being serviced. It’s a good idea to have a thorough engine inspection every year, at which point valve clearance should always be inspected.
What is a common symptom indicating you need to adjust the valve clearance?
- Ticking noise from the engine
How important is this service?
Fuel enters your vehicle’s cylinders via the valves. Each cylinder has a valve, which opens to allow fuel into the cylinder, and then closes to compress the fuel in the cylinder to help combustion and power. This valve is opened and closed by the cam or rocker arms on the camshaft, which, as they rotate, apply pressure on the stem of the valve, which opens the valve. The valve is then closed by a spring. If the clearance between the valve stem and the cam or rocker arm is too large, then the valve will open too late, and close to early, and the cylinder will not get enough fuel. If the clearance is too small, then the valve will not be able to close properly, and the valve will not create enough compression in the cylinder.