Admin How do valve seats work?
The valve seat is a surface inside the body of a valve that comes into contact with the disk, which is a moveable component that restricts and allows flow through the valve. It has several important purposes, including the following: Preventing compressed or combustion gasses from getting into the manifold.
How do you inspect and measure valves and valve stems?
Lightly oil the valve stem and insert it into the cylinder head. Position the dial indicator against the valve stem near the tip and zero the gauge. Grasp the valve stem and wiggle towards and away from the dial indicator and observe the readings.
How do you know if your valve seat is hardened?
A lot of times it is very difficult to see them once a head has been run. What you are seeing is probably just a machinig mark from when the valve seats were cut at the factory. I would look at the date code on the heads. If they are 1973 or newer, they should have hardened seats.
Why must face of valves be seated properly and for what reason?
20.102) or valve face-seating wear. Hard carbon deposits loosen from the combustion chamber sticks between the valve face and seat so that the valve is held slightly off its seat. This reduces valve cooling through the seat and also allows some of the combustion gases to escape.
When should you replace your valve seats?
Another reason to replace a seat is if a valve has broken because the seat is not concentric with the guide. Misalignment between the seat and guide causes the valve stem to flex every time the valve closes. Eventually, this flexing leads to metal fatigue and valve failure.
How can I tell if my valves are seating correctly?
After a few passes, we had made progress, but the pitting remained. Pitting on the valve seat was also still evident. Be sure to periodically lift the valve off the seat and rotate it to spread the compound evenly. With the valves and seats evenly blended together, we can be sure our valves are seating correctly.
What is the best seat width for a valve?
A wide seat also tends to trap deposits that can hold the valve off its seat. This too, can reduce heat transfer as well as compression. As a rule of thumb, the ideal seat width for intake valves is usually around 1/16˝. For exhaust valves, it’s 3/32˝ – or whatever the manufacturer specifies.
What happens if a valve seat is not concentric?
Valve seats must to be cut concentric to the center of the valve guide. Lack of concentricity in the valve seat itself can also prevent the valve from sealing tightly against the seat. As a result, causing a compression leak and a possible misfire.