Processing of valve seats in cylinder head (BMW 5 Series E34)

The treatment of valve seats with increased wear and burning can be performed on all engines as long as the values of correction angles and seat widths can be maintained. A rotary device is used for the treatment of valve seats. It is better to entrust this work to a service station.



Valves with reduced valve edge height H must be replaced. Minimum edge thickness on 520i models produced before April 1990 (M20), 535i/535i:

• Exhaust valve: H = 2.0 mm;
• Inlet valve: H=1.3mm.

When machining the valve seat, ensure the specified valve seat width by machining the correction angle (See Table 1 on the next page).