We check and repair the unit during the overhaul of the engine.

All cylinder block measurements should be made with the block on a level surface and all main bearing caps installed.

Check the cylinder surface for hones.

Проверка и ремонт блока цилиндров Cummins ISF3.8

Crossing lines should be visible on the surface of the cylinder, running at an angle of 20 - 25 ° relative to the upper plane of the cylinder block.

Honed the cylinders if necessary.

Check the main bearing beds.

(a) Install the main bearing caps without bushings.

b) Tighten the main bearing bolts.

Tightening torque 176 Nm

c) Measure the diameter of the main bearing bed. Main bearing bed diameter 87.983 - 88.019 mm

Проверка и ремонт блока цилиндров Cummins ISF3.8

Note: If the diameters of the main bearing seats do not correspond to the nominal ones, check the correct installation and orientation of the main bearing caps. If the main bearing caps are installed correctly, replace the cylinder block.

Check the flatness of the cylinder block using a precision ruler and feeler gauge.

Проверка и ремонт блока цилиндров Cummins ISF3.8

Maximum non-flatness:

- along 0.076 mm;

- across 0.051 mm.

Check for minor irregularities or defects. If present, the upper surface of the cylinder block must be ground.

Note: Grinding of the top surface of the cylinder block is only permitted if the required piston protrusion can then be achieved.

After grinding the upper surface of the cylinder block, the use of repair gaskets is provided. If the required piston protrusion cannot be achieved after grinding, replace the cylinder block.

Measure the inside diameter of the cylinder.

Note: When measuring, honing or reboring cylinders, all main bearing caps must be installed and bolts tightened to rated torque.

a) Check the surface of the cylinders for damage and excessive wear.

Проверка и ремонт блока цилиндров Cummins ISF3.8

b) Using an inside gauge, measure the cylinder diameter at 4 points 90° apart at the extreme positions of the piston stroke.

Measure the cylinder diameter at a depth of more than 50 mm from the top surface of the cylinder block.

Bore 102.01 - 102.03 mm

Maximum ovality 0.038 mm

Maximum taper 0.076 mm

Check the inside diameter of the camshaft bore with the bushing removed.

Проверка и ремонт блока цилиндров Cummins ISF3.8Проверка и ремонт блока цилиндров Cummins ISF3.8

Maximum diameter 59.248 mm

Check tappet bores for damage and wear.

Pusher bore diameter 16.000 - 16.055 mm

Cylinder Block Repair

Note: foreign particles formed during repair operations must not enter the engine oil channels.

Failure to comply with this requirement will result in engine failure.

After boring or honing at a third-party repair shop, it is recommended that you always flush and blow out the cylinder block.

Before repairing the cylinders, be sure to seal the oil channels and the tappet holes in the upper part of the cylinder block with waterproof tape.

Проверка и ремонт блока цилиндров Cummins ISF3.8

Restorative honing of the cylinder liner mirror when gloss is formed on the walls (if necessary).

Honing provides oil retention on the cylinder walls, which is necessary for the normal operation of the piston rings.

Honing is allowed only if the dimensions of the cylinders correspond to the nominal ones.

Note: New piston rings will not fit tightly in glossy cylinders.

Use a round honing head (#3823612 or equivalent) at 300 - 400 rpm, one cycle in the vertical direction per second.

Use a high quality honing oil or an equal parts mixture of SAE 30W engine oil and diesel fuel.

Note: The vertical passages must be smooth and continuous over the full height of the cylinder.

Check cylinder bore after 10 passes.

The angle at which the crossed lines are applied depends on the rotational speed and the vertical speed of the honing head.

Too high or too low a travel speed will cause this angle to deviate from the norm.

On a properly honed cylinder surface, the hone lines should run at an angle of 20 - 25 ° relative to the upper plane of the cylinder block.

Проверка и ремонт блока цилиндров Cummins ISF3.8

Rinse the cylinder block with hot water and detergent concentrate until the remaining abrasive particles are completely removed.

Wash the surface of the cylinders with solvent. Dry the cylinder block with compressed air.

Replacing the cylinder liner

The cylinder block must be bored out to install overhaul liners.

The use of repair sleeves allows the use of pistons and rings of nominal size.

Проверка и ремонт блока цилиндров Cummins ISF3.8

a) Rebore the cylinder to the desired size.

Cylinder bore diameter 104.500 - 104.515 mm

Maximum cylinder bore depth 192.65 mm

Проверка и ремонт блока цилиндров Cummins ISF3.8Проверка и ремонт блока цилиндров Cummins ISF3.8

As a result, a step 6.35 mm high should form in the lower part of the cylinder, on which the sleeve will be planted.

b) Thoroughly clean the cylinder block from metal filings.

c) Place the repair sleeves in a freezer below -12°C for at least 1 hour.

Note: Take out the sleeves one at a time immediately before installation.

Проверка и ремонт блока цилиндров Cummins ISF3.8Проверка и ремонт блока цилиндров Cummins ISF3.8

d) Apply Loctite 620 to the top of the cylinder block bore just before installing the liner

e) Put on protective gloves, use your hands to push the cooled sleeve into the cylinder block as far as possible.

Проверка и ремонт блока цилиндров Cummins ISF3.8

(e) Using a press, press the liner into the cylinder block until it contacts the step at the bottom of the bore.

Проверка и ремонт блока цилиндров Cummins ISF3.8Проверка и ремонт блока цилиндров Cummins ISF3.8

g) Bore the installed sleeve to the nominal size.

Nominal diameter - 101.956 mm

h) Machine the upper part of the liner so that its protrusion is less than 0.05 mm above the surface of the cylinder block

Проверка и ремонт блока цилиндров Cummins ISF3.8

i) After boring with a honing stone, chamfer 1.25 mm deep at an angle of 15° to the vertical

After boring the repair sleeve, two-stage honing is necessary to complete the cylinder.

Use quality honing equipment.

When honing, the rotation speed of the honing head should be 300 - 400 rpm, and the up and down travel time should be 1 second.

Use a good quality honing oil or mix equal parts SAE 30W engine oil and diesel fuel.

For the first honing step, use 80 grit silicon carbide stones.

Honed cylinders to final size.

Diameter 102.00 - 102.04 mm

Проверка и ремонт блока цилиндров Cummins ISF3.8Проверка и ремонт блока цилиндров Cummins ISF3.8

Use 285 grit silicon carbide stones for the second honing step or finish honing. Make 15 to 20 passes to give the desired hone angle.

After processing is complete, thoroughly rinse and blow out all channels from chips, dirt, metal particles and oil.