Kubota EA330-E4 Series Workshop Manual page 110

EA330-E4, WSM
Valve Recessing
1. Clean the cylinder head, the valve face and seat.
2. Insert the valve into the guide.
3. Measure the valve recessing "A" with a depth gauge.
4. If the recession exceeds the allowable limit, replace the valve.
In addition, repair the cylinder head seat surface with a valve
seat cutter or valve seat grinder, and then repair the head
surface with a surface grinder. Or, replace the cylinder head.
Factory specification
Valve recessing
(IN and EX)
Allowable limit
A: Valve recessing
Width of Contact between Valve and Valve Seat
1. Check the contact between the valve face and valve seat.
2. When parts are not contacting evenly, or the contact width "A"
(See figure) is extremely wide, repair or replace the valve and
cylinder head seat, rub and refit parts to each other applying an
appropriate amount of compound.
Valve seat width Factory specification
A: Contact Width
Correcting Valve Face Angle
1. Correct the valve seat to the factory specification with a valve
seat cutter or a valve seat grinder.
2. Correct the valve using a valve refacer.
Valve seat angle
Factory specification
Valve face angle
(1) Valve
(2) Corrected Valve Seat
(3) Valve Refacer
1-S45
ENGINE
0.80 to 0.90 mm
0.032 to 0.035 in.
1.5 mm
0.059 in.
9Y1211018ENS0072US0
2.1 mm
0.083 in.
9Y1211018ENS0073US0
0.785 rad
45.0 °
0.786 to 0.794 rad
45.0 to 45.5 °
(a) 0.26 rad (15 °)
(b) 0.79 rad (45 °)
9Y1211018ENS0074US0
KiSC issued 05, 2015 A