Machine valve seat rings

AR05.30-B-4511A

06.02.2020

Engine

904.9, 906.9 (except 906.999), 924.9 (except 924.92), 926.9 (except 926.942/95) in model 368.0/1, 382.1, 384.06/07, 634.0, 685.282/284/289/290, 979.2

1	Intake valve
2	Exhaust valve
3	Cylinder head
4	Valve seats
5	Dial indicator
6	Dial indicator holder

B05.30-0011-06

4	Valve seats

E	Seat face angle
F	Width of the seat face
G	Diameter of control on the seating face F, relative to the position H
H	Position relative to diameter G

B05.30-0012-06

	Measure
1	Measure the distance between the face of the valves and the cylinder head mating surface (valve recess)	.	AR05.30-B-4100-01A
		 If the value obtained is not within the recommended values, rework or replace the valve (1/2) and/or the seat (4).
		.Distance between valve face and the cylinder head	*BE05.30-B-1001-01D
		 Dial gage	*001589532100
		 Dial indicator holder	*343589004000
	Disassemble
2	Remove the valve (1/2) from the cylinder head (3)	 Mark the valve.
	Check
3	Check the valve guide for wear, replace if necessary	.	AR05.30-B-3731B
		.Valve guide inside diameter (final finish)	*BE05.30-B-1003-02B
4	Check conditions and dimensions of the valve (1/2)	.	AR05.30-B-4202-01A
		Grind valves.	AR05.30-B-4202C
		 Replace the valves when they show signs of wear at the keyway grooves, damage at the end and the chrome layer of the stem, and burned seats.
		 If necessary, rework the valve.
5	Check the valve seat insert (4)	.	AR05.30-B-3831A
		 If necessary, replace the seat.
		 In case of slight deformation of the seat surface, it is possible to rework the seat, provided the distance from the valve to the head, after reworking, is greater than or equal to the allowable minimum value.
	Machining
6	Machining the valve seat (4)	.	AR05.30-B-3831A
		 The number of times the valve seat can be refaced is limited by the distance (B) from the valve to the cylinder head. For new seats, keep the width (F) of the seat wherever possible at the minimum tolerance value.
		 If the values recommended below are not obtained by machining, replace the seat.
		.Angle (E) of the seating face in the valve case	*BE05.30-B-1009-03C
		.Seating face width (F) on valve seat	*BE05.30-B-1010-03C
		.Control diameter (G) in the relative position (H) of the intake case	*BE05.30-B-1011-03C
		.Control diameter (G) in the relative position (H) of the exhaust case	*BE05.30-B-1012-03C
		.Maximum permissible deviation in concentricity of valve seat face (F) to valve guide	*BE05.30-B-1007-03C
7	Check the contact of the seat insert face with the valve	.	AR05.30-B-4532-02A
		 Uniform contact should exist throughout the seat area.
	Assemble
8	Install the valve (1/2).

Test value for the valves

Number	Designation				Engine 904.9 until 415751	Engine 902.9, Engine 906.9 from 415752
BE05.30-B-1001-01D	Distance between valve face and the cylinder head	intake	Normal	mm	1,1...1,5	1,1...1,5
			Maximum repair stage	mm	1,7	1,7
		exhaust	Normal	mm	1,1...1,5	1,1...1,5
			Maximum repair stage	mm	2,0	2,0

Test value for the valves

Number	Designation				Engines 924.9, 926.9
BE05.30-B-1001-01D	Distance between valve face and the cylinder head	intake	Normal	mm	1,1...1,5
			Maximum repair stage	mm	1,7
		exhaust	Normal	mm	1,1...1,5
			Maximum repair stage	mm	2,0

Valves guide check values

Number	Designation			Engine 904.9## ## as of 415752 Engine 906.9
BE05.30-B-1003-02B	Valve guide inside diameter (final finish)	standard	mm	8,000...8,022
		wear limit	mm	8,050