TM 5-3810-300-24 & P2
are a snug fit. In crankshafts fitted with oil seal rings, the oil seal ring groove or grooves must not be worn. The ring
groove walls must have a good finish and they must be square. Check to be sure the oil passages are open through the
Used bearing inserts must be replaced. Connecting rod caps are not interchangeable. The locking slots of the connecting
rod and cap should be positioned adjacent to each other. Clearance between the connecting journal and the connecting
rod bearing must not be less than 0.0003" or more than 0.0021" after rebuilding.
If the discharge valve seats merely show signs of slight
1. Discharge Valves, Valve Stops and Seats.
wear, they can be dressed by using a lapping stone,
grinding compound and grinding tool. If the discharge
valve stops are to be replaced, an application of a sealer
is required, such as "Locktite Retaining Compound #75".
Be sure that the press fit between the discharge valve
stop outside diameter and the valve stop bore in the
cylinder head is a minimum of .0008" and a maximum of
.0028". If this fit can not be maintained, a new cylinder
head body must be used. Be sure to completely support
the outside top of the cylinder head casting, while
pressing in the replacement stops. Install the new
discharge valve springs and valves. Screw in the
discharge valve seats. Discharge valve travel should be
between .041" to .057"
To test for leakage by the discharge valves, apply 100 pounds of air pressure through the cylinder head discharge port and
apply a soap solution to the discharge valves and seats. A slight leakage in the form of soap bubbles is permissible. If
excessive leakage is found, leave the air pressure applied and with the use of a fibre or hardwood dowel and a hammer,
tap the discharge valves off their seats several times. This will help the valves to seat and should reduce the leakage.
With the air pressure still applied at the discharge port of the cylinder head, check for leakage around the discharge valve
stops exposed on the top of the cylinder head casting. No leakage is permitted.
2. Inlet Valves and Seats.