Volvo D20 - Page 52

Group 21 Reconditioning engine
Cylinder head, assembly
so
Heat cylinder head
Heat to 100 "C (212 " F).
Place new seat in installation tool
F16
F17
Use drift 5220 for intake valve seats and 5221 for
exhaust valve seats.
F18
Cool valve seat
Wear protective gloves and safety glasses.
Use
liquid carbon dioxide to cool seat down to -70 "C
(-94 " FI.
F19
Tap-in valve seat
Notel This must be done quickly, within 3-4 seconds
to avoid temperature loss.
F20
Check fit of valve seat
Make sure that the seat has bottomed correctly and is
secure.
If not, replace cylinder head.
F21
Grind valves and mill seats
See instructions on page 48, operations F9-12.