What will happen to a valve with a thin or uneven margin?

What will happen to a valve with a thin or uneven margin?

What will happen to valve with a thin or uneven margin? Burned valve. You just studied 23 terms!

What does the valve margin do?

The margin for an exhaust valve should be larger to improve heat dissipation—generally around 0.080-0.100 inch. Because the flow path for an exhaust valve is the opposite of an intake valve’s, you will sometimes see a smooth radius on the chamber side to improve airflow into the port.

How does a valve get damaged?

Burnt valves occur when the valve can no longer seal correctly after excessive temperatures have damaged the material of the valve. When this happens, combustion gases are able to escape. These gases will start to burn the edges of the valve as they are forced through it.

What happens if the valve clearance is too large?

Too much or too little valve clearance can result in poor performance or a rough idle because the engine can’t “breathe” normally and operate at peak efficiency. Too much clearance means the valves will likely clatter and, over the long term, cause damage to the valves, camshaft lobes or rocker arms.

What happens during a valve job?

Answer: A valve job is removing the cylinder head(s) from the engine so the valves, guides and seats can be refurbished to restore compression and oil control. A valve job may be necessary by the time an engine has 80,000 or more miles on it, or to fix a “burned valve,” compression or oil burning problem.

What happens when valve spring tension is too low?

If spring tension is too light, valve float and eventual engine damage can occur. Valve float, which can cause a sudden, dramatic loss of power, occurs when spring tension is not great enough to allow the lifter to follow the cam lobe properly.

What causes intake valves to break?

1 Fresh air intake systems, same conditions as overfueling. Not enough fresh air to properly balance fuel/air ratio. 2 Exhaust restrictions. Not enough flow to allow enough fresh air to enter the combustion chamber.

What happens when the valves open and close?

The other two valves, the aortic and pulmonary valves, move blood to the lungs and the rest of the body through the ventricles. When the heart valves open and close, they create sounds we know as our heartbeat. Here is an overview of circulation through the heart: First, blood returns from the body to the right atrium.

What causes weak valve springs?

If your engine is misfiring and losing power at higher engine speeds, the problem may be weak valve springs or fuel starvation due to a weak fuel pump, dirty fuel injectors, clogged fuel filter or fuel line obstruction. Bad gas can also cause high speed misfires as can a weak ignition system.

What happens when a valve is not given enough clearance?

If sufficient clearance is not given, the valve will not seat properly when the engine becomes heat, which will cause power loss and lifting of the valve. It is better to have more clearance than necessary rather than to have too little, in spite of the slight increase in noise of the valve mechanism.

How to reduce the risk of valve related problems?

To reduce valve related problems, you should do the following: 1) Analyze the amount of wear as well as wear patterns in the head and valvetrain components when the head is disassembled. A careful inspection should reveal any abnormal conditions or wear patterns that would indicate additional problems.

What can cause damage to a valve head?

Insufficient valve guide clearance. The guide diameter has been dimensioned too small during replacement of the valve guides. Inadequate lubrication, stiffness and seizures of the valve stem in the guide. Consequential damage such as overheating of the valve head or seat area can occur.

What causes a valve to go into the discard pile?

Obvious problems such as a bent valve stem, mushroomed or grooved valve tip, burned, eroded or cracked valve head, thin valve margin, valve elongation (stretch), or excessive stem wear or galling will result in the valve being tossed into the discard pile. Otherwise, the valves are refinished and reused.