TM 55-1930-209-14&P-21
(5)
Install bearing shells and connecting rod caps as outlined in para 6-38.
(6)
Remove liner hold-down clamps.
j.
Complete installation of pistons and connecting rods (para 6-34).
k.
Remove engine from overhaul stand. Install engine assembly.
Section X. Crankshaft and Main Bearings
6-38
General
a.
Crankshaft
(1)
Crankshaft one piece of steel forging, heat-treated to ensure strength and durability. All main bearings and
connecting rod bearing journal surfaces and oil seal surfaces are induction hardened.
(2)
Complete static and dynamic balance of crankshaft is achieved by counterweights incorporated in
crankshaft.
(3)
Crankshaft thrust is taken through two-piece washers on each side of rear main bearing. Full pressure
lubrication to all connecting rod and main bearings is provided by drilled passages within crankshaft and cylinder block.
b.
Main Bearings
(1)
Engine is equipped with a front and rear main bearing and three intermediate main bearings.
(2)
Main bearing shells are precision type and are readily replaceable without machining. Upper main bearing
half is seated in cylinder block support and lower bearing half is seated in main bearing cap. Bearing shells are
prevented from movement by a tang at parting end of each shell. Each bearing cap is numbered 1, 2, 3, and 4 and when
removed, must always be reinstalled in their original position.
(3)
Rear main bearing thrust washers absorb crankshaft thrust at each side of rear main bearing. Each washer
is made of two halves; lower halves are doweled to bearing cap; upper halves are not doweled.
6-39
Crankshaft and main bearing removal and disassembly
a.
Removal
WARNING
Be absolutely sure engine is securely attached to stand before releasing lifting sling.
Severe injury to personnel and destruction of engine parts will result if engine breaks
away from stand.
(1)
Remove engine assembly and install it on a suitable overhaul stand.
(2)
Remove cylinder head (para 6-16).
6-69
