Cylinder head (BMW 7 Series E32)

Carefully inspect the cylinder head for cracks, signs of coolant leakage, or other damage. If there are cracks and they cannot be repaired in a specialized workshop, the head must be replaced.

Using the edge of a ruler and a feeler gauge, check whether the surface of the cylinder head that contacts the cylinder block is deformed.



If the deformation is greater than the maximum permissible value (0.05 mm), the surface must be machined without exceeding the required maximum permissible value.

Check the valve seats in each combustion chamber. If they are burned, cracked or have pitting, the valve seats must be replaced.

Check the clearance between the valve stem and the valve guide by measuring the horizontal clearance of the stem using a gauge with an indicator. To determine the clearance between the stem and the valve guide, swing the stem and take measurements at the extreme points using an indicator. The valve should be raised by approximately 1.5 mm. To obtain the true clearance value, divide the result by two. If the clearance is greater than the permissible value, the guide bushings must be replaced.

Valves

Carefully inspect each valve for signs of wear, cracks, dents, or burnt areas. Rotate the valve to see if it is bent. If any of these are found, the valve must be repaired at a specialist workshop.



Check the valve for wear.



Measure the amount of protrusion of each valve relative to the seat (for the intake valve - 1.191 mm, for the exhaust valve - 1.98 mm). If it is less or absent, the valve must be replaced.

Valve parts

Check each valve spring for wear (at the ends) and pitting. Measure the free length and compare with the technical data. Springs shorter than the permissible length cannot be used again. The tension of all springs must be checked with a special device before deciding on their suitability (these measurements are carried out in a specialized workshop).

Place each spring on a flat surface and check for squareness.

If the springs are deformed, replace them as they may cause accelerated wear of the guide bushings.



Check the plates and holders for wear and cracks. Any questionable parts should be replaced with new ones.

Rocker arm parts

Check the rocker arm areas that contact the pushrod ends and valve stems for pitting, wear, plaque, and scratches. Also check the joints. Check for cracks in the rocker arms, bolts, and nuts.





All damaged or badly worn parts should be replaced with new ones.

If the inspection shows that the valve parts are in poor condition and worn beyond the permissible limits (what usually happens in engines undergoing repair) it is necessary to replace or grind the valves and seats.