Valve seats in the cylinder head. Valve repair (Audi 80 B3)

Valve seats with signs of wear and pitting can be repaired as long as the maximum permissible size is maintained. If this size is exceeded, reliable operation of the hydraulic compensation of the hydraulic valve lifters is not ensured. In this case, the cylinder head is replaced. Valve seats are repaired in such a way as to obtain a reliable contact patch. Valve seats can be replaced using conventional technical means. Repair of valve seats is performed using reamers. Since this requires special skills, this work must be performed in special workshops.

Note: The exhaust valve seats have an additional narrowing. When machining the seats, care should be taken not to damage the radius of this narrowing.

Note: The exhaust valve seats have an additional narrowing. When machining the seats, care should…

Calculation of the maximum allowable processing size.

Insert the valve and press it against the seat.

Measure the distance "a" between the end of the valve stem and the top edge of the cylinder head.

Measure the distance «a» between the end of the valve stem and the top edge of the cylinder head.

Measure the distance «a» between the end of the valve stem and the top edge of the cylinder head.

To maintain the maximum allowable processing size, it is necessary to subtract the maximum size from the measuring distance "a", i.e.

...mm = measured distance "a"
-..mm = minimum size
...mm = max. allowable processing size

Gasoline engine intake valve seat

Exhaust valve seat of a gasoline engine

For geometric parameters of the valve seat, see chapter "Repair characteristics".

For valve dimensions, see chapter "Repair characteristics".

The exhaust valves are sodium filled and cannot be crushed any more. Use a hacksaw to split the valve into two parts at the center of the stem. Do not allow water to get on the valve. Then throw the valve parts into a bucket of water and step away.