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VALVE LIFTERS
When removing the lifters, mark the lifters to install the lifter in the same position as it was removed from. The
valve lifters may be slightly different lengths. Visually check the lifter for wear on the cam contact surface and
push rod contact surface.
VALVE GUIDES
Engine models OVM, OHM, OHSK80 - 130, and OVXL have valve guides that can be reamed 1/32" (.794 mm)
oversize or be replaced as service parts. All other overhead valve engines have valve guides that are permanently
installed in the cylinder head. If the guides get worn excessively, they can be reamed oversize to accommodate
a 1/32" (.794 mm) oversize valve stem.
The guides should be reamed oversize with a straight shanked hand reamer or low speed drill press. Refer to
the "Table of Specifications" (Chapter 10) to determine the correct oversize dimension. Reamers are available
through your local Tecumseh parts supplier. Consult the tool section in Chapter 11 for the correct part numbers.
The upper and lower valve spring caps must be redrilled to accommodate the oversize valve stems.
After oversizing the valve guides, the valve seats must be recut to align the valve seat to the valve guide.
VALVE GUIDE REMOVAL (WHERE APPLICABLE, CONSULT PARTS MANUAL)
4. Place the head on the bed of an arbor press on parallels with the snap rings on the long ends of the
guides facing down.
5. Using a 1/2" (12.7 mm) diameter, 6" (15.24 cm) drift punch located in the center of the old valve guide,
push the guide out of the head with the arbor press. Do not allow the drift punch to contact the head
during this step.
VALVE GUIDE INSTALLATION
1. Install the snap rings on the new replacement valve guides. Place the valve guides in a freezer for an
hour or longer to ease assembly.
2. Submerge the head in a container of oil so that the valve guide bores are completely covered with oil.
Heat the container on a hot plate approximately 15-20 minutes until the oil begins to smoke. Oil
temperature must be 375
o
- 400
o
F (190
0
- 204
0
C).
CAUTION : USE PROTECTION FOR EYES AND HANDS, BE CAREFUL ! THE HOT OIL AND
HEAD CAN EASILY CAUSE BURNS.
3. Using a pliers, remove the head from pan of oil. Carefully drain the excess oil out of the head. Quickly
work the next two steps while the head is hot to prevent damage to the guides or the head.
4. Place the head on a 6" x 12" (15.24 x 30.5 cm) piece of wood with the head gasket surface down.
5. Insert the new guides in the head with the long end of the guides up. It may be necessary to use a
rubber or rawhide mallet to fully seat the new guide to the snap ring.
NOTE:
DO NOT USE A STEEL HAMMER TO SEAT THE NEW GUIDE, GUIDE OR HEAD DAMAGE
WILL RESULT.
6. Allow the head to cool and re-cut both valve seats using a Neway cutter to align the new guides to the
valve seats.
1. Submerge the head in a container of oil so
that both guides are completely covered with
oil.
2. Heat the oil on a hot plate approximately 15-
20 minutes until the oil begins to smoke. Oil
temperature must be 375
o
- 400
o
F (190
0
-
204
0
C).
CAUTION : USE PROTECTION FOR EYES
AND HANDS, BE CAREFUL ! THE HOT OIL
AND HEAD CAN EASILY CAUSE BURNS.
3. Using a pliers, remove the head from pan of
oil. Carefully drain the excess oil out of the
head. Quickly work the next two steps while
the head is hot to prevent pressing the guides
out with the head too cool. Guides removed
too cool will permanently damage the head
by removing aluminum necessary to hold the
new guides in place.
GUIDES
HEAD
OIL
HOT PLATE
HEAT UNTIL OIL BEGINS TO SMOKE
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