Kohler KT19 series II User Manual

When replacing valve seat inserts, measure the
width of the insert before removal to be sure you
order the correct size insert for your cylinder
barrel. (See Figure 7-8.)
Two different width inserts have been used due to a
change of cylinder barrels and the inserts are not
interchangeable:
Width .199 (.200/.198)
Width .220 (.221/.219)
The inserts are a tight press fit in the cylinder
barrel. A commercial valve seat removal tool is
recommended for this job. Since insert removal
causes loss of metal in the insert bore area, use
only Kohler service replacement inserts which are
slightly larger to provide proper retention in the
cylinder barrel. Make sure new inserts are properly
started and pressed into bore to prevent cocking of
the insert.
Seating surfaces should be held between .037" and
.045" width. Seats with more than .045" must be
reconditioned with a 45° cutter and overcutting or
undercutting with 30° and 60° cutters, to obtain the
proper seat width, is recommended. See Figure 7·8
for valve seat details.
Reground or new valves must be lapped in to
provide proper fit. Use a hand valve grinder with
suction cup for final lapping. Lightly coat valve
face with "fine" grade of grinding compound then
rotate valve on seat with grinder. Continue grind·
ing until smooth surface is obtained on seat and on
valve face (see Figure 7-9). Remove all traces of
grinding compound.
Figure 7-9. Lapping Valves
47
Valve Stem Seals
SECTION 7
DISASSEMBLY
Some engines use valve stem seals on the intake
valves. Always use new seals when valves are
removed from cylinder. Seals should also be re-
placed if damaged or deteriorated in any way.
Never reuse old seals.
NOTE: Some early production KT17 models do not
use valve stem seals.
Valve Springs
There are two different valve springs used on these
models: a short spring (free length 1.542") and a
longer spring (free length 1.6876"). The short
spring is used with valve rotators, while the long
spring is used without rotators. Both of the springs
are progressively wound, that is, coils are closer
together on one end than the other. Install springs
with close coils toward cylinder head.
A valve spring will seldom wear out, but if it does,
it will usually break. Broken springs must be
replaced.
Pistons And Rings- Inspection
Scuffing and scoring of pistons and cy Iinder walls
occurs when internal temperatures approach the
welding point of the piston. Temperatures high
enough to do this are created either by friction
which is usually attributed to improper lubrication
and/ or overheating of the engine.
Normally, very little wear takes place in the piston
boss-piston pin area. If the original piston and
connecting rod can be reused after new rings are
installed, the original pin can also be reused but
new piston pin retainers are required. Piston pins
are included as part of the piston assemblies-if
the pin boss in piston, or the pin are worn or
damaged, a new piston assembly is required.
Ring failure is usually indicated by excessive oil
consumption and blue exhaust smoke. When rings
fail, oil is allowed to enter the combustion chamber
where it is burned along with the fuel. High oil
consumption can also occur when gap is incorrect,
rings cannot properly conform to the cy Iinder
walls under this condition. Oil control is also lost
when ring gaps are not staggered during installa·
tion.
When cylinder temperatures get too high, lacquer
and varnish collect on pistons causing rings to
stick which results in rapid wear. A worn ring
takes on a shiny or bright appearance. Scratches
on rings and pistons are caused by abrasive
material such as carbon, dirt, or pieces of hard
metal.

Kohler KT19 series II Specifications

General

Brand	Kohler
Model	KT19 series II
Category	Engine
Language	English