Valve seats — design description (BMW X5 E53)

Valve seats (Fig. 6.9) are made of austenitic steel obtained by powder metallurgy and are not subject to replacement. If traces of burning or wear are detected, the cylinder head is replaced entirely. The valve seat is not ground in or repaired.

Valve seat characteristics

Parameter	Valve seat
	intake	graduation
Valve seat diameter, mm	25,9	25,9
Working chamfer angle, deg.	45	45
Correction angle, external	15	15
Correction angle, internal	60	60
Working chamfer width, mm	1,45±0,25