Chamfering of valve seats in cylinder heads / valve machining (Mazda Familia BG)

Valve seat chamfers with signs of wear or carbon deposits can be machined as long as the maximum permissible machining dimensions, correction angles and chamfer widths are maintained. Otherwise, the cylinder head must be replaced. Valve seats can be replaced by conventional means. A special device is required for machining. This work must be carried out in a specialist workshop. For engine identification, see Chapter Introduction.

Angles on valve chamfers

1. To check the working surface and the width of the valve chamfer, the valve chamfer should be coated with a thin layer "Preussischblau" (prussian blue) or "Bleiweiss" (white lead). Insert the valve and press lightly on the seat chamfer.

Attention! Do not rotate the valve. If the color is not evenly distributed, the valve chamfer should be processed further. In this case, the maximum or minimum chamfer width must not be exceeded, see valve size table.

2. After machining the valve chamfers, the valve protrusion value "L" should be checked. If the value is within the range of -a-, the protrusion value is normal; if the value is within the range of -b-, the protrusion value should be adjusted by installing a washer to achieve the value -a-. If the maximum value -b- is exceeded, the cylinder head should be replaced.

Valve sizes

Engine designation	Values in mm
	Valve length	Valve chamfer width	Thickness on the edges of the valve	Valve protrusion "L"
E1, E3, E5	__	1,4	In. 0.10 Issue 0.10	a = 42.4 b = 42,9 — 43,9
B3, up to 8/89	__	1,1 — 1,7	Vp. 0.50 Issue 1.00	a = 39.0 - 39.5 b = 39,5 — 40,5
VZ since 9/89	Vp. 103.84 Yield 104.94	0,8 — 1,4	Vp. 1.00 Issue 1.00	a = 41.5 - 42.0 b = 42,0 — 43,0
B5	__	1,1 — 1,7	Vp. 0.50 Issue 1.00	a = 39.0 - 39.5 b = 39,5 — 40,5
B6 TO 9/89	__	1,1 — 1,7	Vp. 1.00 Issue 1.30	a = 39.5 - 40.0 b = 40,0 — 41,0
B6 from 9/89	Vp. 103.84 Issue 104.94	0,8 — 1,4	Vp. 0.90 Issue 1.00	Inlet a = 41.5 - 42.0 b = 42,0 — 43,0 Release a = 41.5 - 42.0 b = 42,0 — 43,0
VRE (SOHC)	Vp. 101.77 Issue 102.97	0,8 — 1,4	Vp. 0.65 Issue 1,20	Inlet a = 42.5 - 43.0 b = 43,0 — 44,0 Release a = 41.0 - 41.5 b = 41,5 — 42,5
VRE (DOHC) up to 8/89	__	0,8 — 1,4	Vp. 1.00 Issue 1.00	a = 43.5 - 44.0 b = 44,0 — 45,0
VRE (DOHC) since 9/89	Vp. 101.34 Issue 101.44	0,8 — 1,4	Rep. 1.35 Issue 1.45	a = 45.0 - 45.5 b = 45,5 — 46,5
VZE	Vp. 105.27 Issue 104.17	1,1 — 1,7	Vp. 0.50 Issue 1.00	a = 39.0 - 39.5 b = 39,5 — 40,5
B6E	Vp. 103.77 Issue 102.67	1,1 — 1,7	Vp. 0.50 Issue 1.00	a = 39.0 - 39.5 b = 39,5 — 40,5
PN	Vp. 101.50 Issue 101.40	1,4 — 1,8	Vp. 0.50 Issue 0.50	a = 36.8 - 36.9