Valve Seat, Changing - Volvo Penta TD520GE Workshop Manual

Checks and adjustments

Valve seat, changing

(21405, 21406)
Cylinder head removed
100
1. The valve seats shall be changed when the
measurement between the valve disc and
cylinder head face exceeds the value given in
the specification or when the tightness is not
satisfactory. Max. 1.5 mm.
2. Cut off the face of an old valve and weld it
to the valve disc. Use a MAG-weld or
alternatively a conventional arc welder (with
a stainless welding electrode).
IMPORTANT! Carefully cover other surfaces
on the cylinder head so that possible welding
sparks can not stick.
3. Place a suitable socket over the valve/valve
guide and carefully knock out the valve seat.
NOTE! Be careful so that the cylinder head is not
damaged.
4. Clean the location of the seat carefully and
check the cylinder head for cracks.
5. Measure the diameter of the valve seat
location. Check whether a seat of standard size
or an oversize seat should be used. Perform
possible work to the location of the valve seat,
see "Technical Data".
6. Cool the seat, using carbon dioxide snow, to
between -60°C (-76°F) and -70°C (-94°F) and
heat the cylinder head, for example by running
hot water over it.
Using a drift, press in the valve seat.
NOTE! Turn the seat so thet the seat angle faces the
tool.
Group 21