Mitsubishi S12A2 User Manual

5-22
Chapter 5 DISASSEMBLY OF BASIC ENGINE
5. Crankcase, Crankshaft and Main Bearing - Disassemble and Inspect
Understanding of the current engine condition before disassembling is very important to know the cause of trouble and do the
efficient work.
Depending on the maintenance work or purpose, it is desirable to inspect some of the following items before proceeding with
any job.
Crankshaft End Play - Measure
Crankcase, Crankshaft and Main Bearing - Disassemble and Inspect
11
10
8
7
6
5
4
3
2
1
9
Scale deposit, flaw,
crack, oil hole clogging
Inner and outer peripheral
face flaw, corrosion, flaking
Wear, flaw, crack
Inner and outer
peripheral face flaw,
corrosion, flaking
Flaw
Peeling, wear, contact
Wear
Valve operation,
oil hole clogging
Local contact, crack on counterbore,
fretting/corrosion on fitting bore of
cylinder liner
Crack
Wear
Replace
Flaw
Oil jet pipe bend,
deformation
Disassembling Sequence
1 Main bearing cap bolt
2 Side bolt
3 Main bearing cap
4 Lower main bearing
5 Lower thrust plate
6 Crankshaft (Approx. 300 kg [661 lb.])
7 Upper main bearing
8 Upper thrust plate
9 Check valve
10 Piston cooling nozzle
11 Crankcase (Approx. 1010 kg [2227 lb.])

Mitsubishi S12A2 Specifications

General

Brand	Mitsubishi
Model	S12A2
Category	Engine
Language	English