Contents: Checking the thermal clearance of…↓ Checking the piston ring clearance…↓ Checking the cylinder diameter ↓ Mounting position and belonging of…↓ Piston and cylinder dimensions ↓ Checking the piston protrusion at…↓ Cylinder Head Gasket Markings ↓
Fig. 2.285. Piston and connecting rod: 1 – piston rings; 2 – piston; 3 – piston pin; 4 – retaining ring; 5 – connecting rod; 6 – bearing shell; 7 – cylinder block; 8 – connecting rod cover; 9 – oil injection nozzle; 10 – bolt 25 Nm; 11 – connecting rod bolt, 30 Nm + turn further by 1/4 turn (90°)
Note: To perform installation work, it is necessary to secure the engine using the engine and gearbox clamp on the mounting stand or on the engine and gearbox clamp.
Note: All support and working surfaces must be lubricated with engine oil before installation.
Checking the thermal clearance of piston rings
Fig. 2.156. Checking the thermal gap
Drive the piston ring from above, at a right angle to the cylinder wall, to the bottom hole of the cylinder, at a distance of about 15 mm from its edge (fig. 2.156).
Checking the piston ring clearance by height
Clean the ring groove before checking.
Checking the cylinder diameter
Fig. 2.159. Cylinder diameter check diagram
Measure the transverse distance A and the longitudinal distance B in three places in a cross shape (fig. 2.159). Maximum permissible deviations from the nominal size are max. 0.10 mm.
Note: Do not measure cylinder diameters while the cylinder block is mounted on the engine support of the assembly stand, as this may result in incorrect results.
Mounting position and belonging of pistons to cylinders
Fig. 2.286. Mounting position and belonging of pistons to cylinders
The arrows in Figure 2.286 show the direction to the first cylinder (fig. 2.286).
Piston and cylinder dimensions
Checking the piston protrusion at top dead center
Fig. 2.287. Checking the piston protrusion at top dead center
When installing new pistons or a new engine component, check the position of all pistons at top dead center. Depending on the piston protrusion, install the appropriate cylinder head gasket according to the following table
Note: To measure piston position at top dead center, rotate the crankshaft clockwise.
Note: If different piston protrusion values are obtained when measuring pistons, use the largest size to ensure compatibility with the seal.
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Cylinder Head Gasket Markings
Fig. 2.288. Cylinder head gasket markings
Part number – 1.
Control code - 2 (does not contain important information).
Holes – 3.
Mounting position: marking facing up.
Note: The thickness of the cylinder head gasket to be installed depends on the piston protrusion. When replacing, install a gasket with identical marking 3.
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