47
Group 21 Short block
Camshafts and valve lifters, inspection
Check, using a steel ruler (1), that valve lifter contact
surface facing the camshaft is convex or flat. If the
surface is concave, change the valve lifter.
If the valve lifter is worn all across the lifting surface,
the valve lifter should be scrapped. “The ditch” shows
that the lifter has not been turning.
A dark line on the outside of the valve lifter shows
that the surface is not worn, on the other hand. The
condition of the valve lifters determines whether it is
necessary to check for camshaft wear.
Check that the lifting surfaces on the camshaft and
the valve lifters do not have large areas of pitting
damage. Pitting damage can occur for various rea-
sons. The damage is caused when small pieces of
metal loosen from the hardened surface. Lifters and
camshafts with minor pitting damage can be used.
Pitting damage seldom become worse.
Check that the camshaft bearing surfaces and cam
curves are not abnormally worn.
Change the camshaft if major damage or wear occurs.
NOTE! When replacing camshaft, all valve lifters
should be replaced too.
Guidelines for replacement
In normal conditions, un-evenness may occur on the
camshaft lobes in the engine. This does not mean
that the camshaft has to be changed. These marks do
not have any negative influence on either engine per-
formance or durability of the engine and its compo-
nents.
The next pages shows examples of acceptable wear
and non-acceptable wear.
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