Contents: Assessment of the condition of the…⤓ Checking the warping of the cylinder…⤓ Checking the cylinder mirror ⤓ Checking the clearance between the…⤓ Cylinder boring ⤓ Repair dimensions of the piston and…⤓
Assessment of the condition of the cylinder block
Visually inspect the cylinder block for gasket residue or other foreign particles, damage, rust and corrosion. If defects are found, eliminate them or replace the cylinder block.
Check the cylinder block with a liquid solution to determine if there are any cracks. If the defects are obvious, replace or repair the cylinder block.
Attention! On models with manual transmission, do not unscrew the flywheel mounting bolts "A", which are shown in the figure, since their removal will disturb the flywheel balance, which will lead to various malfunctions and damage to the flywheel.
Checking the warping of the cylinder block mating surface
Using a straightedge and a flat feeler gauge, check the degree of warpage of the cylinder block working surfaces in the directions shown in the figure. The cylinder block surface must be cleaned of foreign particles.
- Standard value: 0.05mm or less.
- Maximum permissible value: 0.1 mm.
If the warping is significant, correct the defect to an acceptable value or replace the cylinder block. Maximum grinding depth: 0.20 mm.
Attention! The total thickness of the metal removed from the cylinder head and cylinder block must not exceed 0.2 mm in total.
Height of cylinder block (new)
- Engine 4G63–7: 290 mm.
- Engine 4G64: 290 mm.
- Engine 4G69: 284 mm.
Checking the cylinder mirror
Check the cylinder bore for scratches and signs of seizure (scoring). If defects are visible, bore to repair size or replace the cylinder block.
Checking the clearance between the piston (with connecting rod assembly) and the cylinder
Using a bore gauge, measure the cylinder diameter and cylinder taper. If there is noticeable wear, bore the cylinder to the repair size, replace the piston and piston rings as a set.
Standard value of the internal diameter of the engine cylinder
- 4G63-7: 85.00–85.03 mm.
- 4G64: 86.50–86.53 mm.
- 4G69: 87.00–87.03 mm.
- Maximum permissible taper (deviation from cylindricity): 0.01 mm.
Cylinder boring
Rebore all four cylinders to the same oversize.
Do not bore just one cylinder.
Based on the largest diameter of the cylinder of the engine being repaired, obtained as a result of measurements, determine the repair size number of the pistons.
The piston repair size number is stamped on the piston bottom.
Repair dimensions of the piston and corresponding piston rings
Measure the outside diameter of the piston to be used at the location shown in the illustration.
Based on the measured piston outside diameter, calculate the cylinder bore diameter using the following formula: cylinder bore diameter = piston outside diameter + (clearance between piston and cylinder) – 0.02 mm (honing allowance).
Bore all cylinders to the calculated diameter.
Engine 4G63-7
Engine 4G64
[The original was published on the website: mitsubishiman.ru]
Engine 4G69
Attention! To prevent temperature deformations during boring, bore the cylinders in the following sequence: No.2, No.4, No.1, No.3.
Hone the cylinders to the final finished dimension (piston outside diameter + piston to cylinder clearance).
Attention! To prevent temperature deformations during boring, bore the cylinders in the following sequence: No.2, No.4, No.1, No.3.
Check the clearance between the piston and the cylinder.
Clearance between piston and cylinder: 0.02–0.04 mm.