116-2
Cylinder Head
This section provides the specifications
and special reconditioning information
necessary to repair the cylinder heads
covered by this manual.
The disassembled cylinder head
should be inspected for warpage and
cracks. Check the valve guides and
valve seats for wear before machining a
warped head. Always decarbonize and
clean the head before inspecting it. A
high-quality straight edge can be used
to check for warpage.
Visually inspect the cylinder head for
cracks. If a cracked cylinder head is
suspected and no cracks are detected
through the visual inspection, have the
head further tested for cracks by an
authorized BMW dealer or an ASE
certified machinist. A cracked cylinder
head must be replaced.
Note:
When disassembling and inspecting the
cylinder head on an engine, be sure to
check the camshaft carrier bearing
surfaces for warpage.
A warped cylinder head can be
machined provided no more than 0.3
mm (0.012 in.) of material is removed. If
further machining is required, the head
should be replaced. Removing more
than this amount will reduce the size of
the combustion chamber and adversely
affect engine performance. A 0.3 mm
thicker gasket is available from an
authorized BMW parts department for
machined heads.
Before machining the head to correct
for warpage, measure the total height
(
A
) (thickness of the cylinder head).
Minimum height specifications are
Cylinder Head and Valvetrain
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Summary of Contents for 1999-2005 M3
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