Kia Niro: Cylinder Block / Piston and Connecting Rod Repair procedures

Kia Niro 2017 (DE HEV) Service Manual / Engine Mechanical System / Cylinder Block / Piston and Connecting Rod Repair procedures

Disassembly

•	Be sure to read and follow the “General Safety Information and Caution” before doing any work related with the high voltage system. Failure to follow the safety instructions may result in serious electrical injuries.

•	Be sure to shut off the high voltage circuit according to the “High Voltage Shut-off Procedures” before doing any work related with the high voltage system to avoid serious electrical injuries.

•	Turn the crankshaft pulley so that the No.1 piston is at TDC (Top dead center).

•	Use fender covers to avoid damaging painted surfaces.

•	To avoid damaging the cylinder head, wait until the engine coolant temperature drops below normal temperature before removing it.

•	When handling a metal gasket, be careful not to fold the gasket or damage the contact surface of the gasket.

•	To avoid damage, unplug the wiring connectors carefully while holding the connector portion.

Mark all wiring and hoses to avoid misconnection.

1.	Shut off the high voltage circuit. (Refer to Engine Mechanical System - “High Voltage Shut off Procedure”)

2.	Remove the engine assembly from the vehicle. (Refer to Engine and Transaxle Assembly - “Engine and Transaxle Assembly”)

3.	Remove the dual clutch transmission. (Refer to Dual Clutch Transmission (DCT) - "Dual Clutch Transmission Assembly")

4.	Install the engine to engine stand for disassembly.

5.	Remove the intake manifold. (Refer to Intake and Exhaust System - "Intake Manifold")

6.	Remove the exhaust manifold. (Refer to Intake and Exhaust System - "Exhaust Manifold")

7.	Remove the hybrid starter generator (HSG). (Refer to Hybrid Motor System (HSG) - "Hybrid Starter Generator (HSG)")

8.	Remove the timing chain. (Refer to Timing System - “Timing Chain”)

9.	Remove the Cylinder head assembly. (Refer to Cylinder Head Assembly - "Cylinder Head")

10.	Remove the Fly Wheel. (Refer to Cylinder Block - "Fly Wheel")

11.	Remove the thermostat. (Refer to Cooling System - "Thermostat")

12.	Remove the water pump assembly. (Refer to Cooling System - " Water Pump")

13.	Remove the A/C compressor. (Refer to Heating, Ventilation Air conditioning -"Compressor")

14.	Remove the oil filter. (Refer to Lubrication System - "Engine Oil")

15.	Remove the oil screen. (Refer to Lubrication System - "Oil Pan")

16.	Remove the ladder frame mounting bolt.

17.

Using the SST (09215-3C000) and remove the ladder frame (A).

•	Insert the SST between the ladder frame and the cylinder block by tapping it with a plastic hammer in the direction of ① arrow.

•	After tapping the SST with a plastic hammer along the direction of ② arrow around more than 2/3 edge of the ladder frame, remove it from the cylinder block.

•	Do not turn over the SST abruptly without tapping. It be result in damage of the SST.

18.	Check the connecting rod side clearance.

19.	Check the connecting rod bearing cap oil clearance.

20.

Remove the piston and connecting rod assembly.

(1)	Using a ridge reamer, remove all the carbon from the top of the cylinder.

(2)	Remove the connecting rod bearing caps (A).

(3)

Push the piston and connecting rod assembly (B) with upper bearing through the top of the cylinder block.

•	Mark the connecting rod and bearing caps to be able to reassemble in the original position and direction.

•	Keep the connecting rod and caps with the bearings assembled together.

•	Arrange the piston and connecting rod assemblies in the correct order.

•	Mark the piston and connecting rod assembly to be able to reassemble in the original position.

21.	Check fit between piston and piston pin. Try to move the piston back and forth on the piston pin. If any movement is felt, replace the piston and pin as a set.

22.

Disassemble the piston rings.

(1)	Using a piston ring expender, remove the two compression rings.

(2)

Remove the two side rails and coil spring.

Arrange the piston rings in the correct order.

23.

Disassemble the connecting rod from the piston.

(1)	Remove the snap ring (A) from the piston.

(2)	Remove the piston pin (B) from the piston.

(3)	Disassemble the piston (C) and connecting rod (D).

Inspection

Connecting Rod

Check the connecting rod side clearance.

Using a feeler gauge, measure the end play while moving the connecting rod back and forth.

•	If out-of-tolerance, install a new connecting rod.

•	If still out-of-tolerance, replace the crankshaft.

Side clearance :

Standard: 0.10 - 0.25 mm (0.0039 - 0.0098 in.)

Check the connecting rod bearing oil clearance.

(1)	Check that the match marks on the connecting rod and cap are aligned to ensure correct reassembly.

(2)	Remove 2 connecting rod cap bolts.

(3)	Remove the connecting rod cap and lower bearing.

(4)	Clean the crank pin and bearing.

(5)	Place a plastigage across the crankshaft pin journal.

(6)

Reinstall the lower bearing and cap, and torque the bolts.

Tightening torque :

[10.8 - 14.7 N·m (1.1 - 1.5 kgf·m, 8.0 - 10.9 lb·ft)] + [88 - 92°]

•	Always use new connecting rod cap bolts. Connecting rod cap bolts are torque-to-yield bolts designed to be permanently elongated beyond the state of elasticity when torqued. Reusing the removing bolts can cause the bolts to break or fail to maintain clamping force.

•	Do not turn the crankshaft.

(7)	Remove the connecting rod cap and lower bearing.

(8)

Measure the width of the plastigage at its widest point.

Oil clearance

Standard ;

0.018 - 0.036 mm (0.0007 - 0.0014 in.)

Limit :

0.030 - 0.056 mm (0.0012 - 0.0022 in.)

(9)

If the measurement from the plastigage is too wide or too narrow, remove the upper and lower bearing and then install new bearings with the same color mark. Recheck the oil clearance.

Do not file, shim, or scrape the bearings or the caps to adjust clearance.

(10)

If the plastigage shows the clearance is still incorrect, try the next larger or smaller bearing. Recheck the oil clearance.

•	If the proper clearance cannot be obtained by using the appropriate larger or smaller bearings, replace the crankshaft and repeat the check procedure.

•	If the marks are indecipherable due to an accumulation of dirt and dust, clean with solvent or detergent instead of scrubbing them with a wire brush or scraper.

Connecting Rod Identification Mark

Connecting Rod Specifications

Class	Mark	Inside Diameter
0	A	42.000 - 42.006 mm (1.65354 - 1.65378 in.)
1	B	42.006 - 42.012 mm (1.65378 - 1.65402 in.)
2	C	42.012 - 42.018 mm (1.65402 - 1.65425 in.)

Crankshaft Pin Identification Mark

Conform to the stamping order in the direction of the arrow from #1.

Crankshaft Specifications

Class	Mark	Outside Diameter Of Pin
I	1	38.966 - 38.972 mm (1.53409 - 1.53433 in.)
II	2	38.960 - 38.966 mm (1.53386 - 1.53409 in.)
III	3	38.954 - 38.960 mm (1.53362 - 1.53386 in.)

Connecting Rod Bearing Identification Mark

Connecting Rod Bearing Specifications

Class	Mark	Connecting Rod Bearing Thickness
A	Blue	1.514 - 1.517 mm (0.0596 - 0.0597 in)
B	Black	1.511 - 1.514 mm (0.0595 - 0.0596 in)
C	None	1.508 - 1.511 mm (0.0594 - 0.0595 in)
D	Green	1.505 - 1.508 mm (0.0593 - 0.0594 in)
E	Yellow	1.502 - 1.505 mm (0.0591 - 0.0593 in)

(11)

Select a connecting rod bearing using selection chart.

Selection Chart For Connecting Rod Bearings

Assembling Classification Of Bearing		Connecting Rod Identification Mark
Assembling Classification Of Bearing		0 (A)	1 (B)	2(C)
Crankshaft Identification Mark	I (1)	E (Yellow)	D (Green)	C (None)
	II (2)	D (Green)	C (None)	B (Black)
	III (3)	C (None)	B (Black)	A (Blue)

Check the connecting rods.

(1)	When reinstalling, make sure that cylinder numbers marked on the connecting rod and cap match during disassembly. When a new connecting rod is installed, make sure that the notches for holding the bearing in place are on the same side.

(2)	Replace the connecting rod if it is damaged on the thrust faces at either end. Also if step wear or a severely rough surface of the inside diameter of the small end is apparent, the rod must be replaced as well.

(3)

Using a connecting rod aligning tool, check the rod for bend and twist. If the measured value is close to the repair limit, correct the rod by a press. Any connecting rod that has been severely bent or distorted should be replaced.

Allowable bend of connecting rod :

0.05 mm (0.0020 in.) or less for 100 mm (3.94 in.)

Allowable twist of connecting rod :

0.10 mm (0.0039 in.) or less for 100 mm (3.94 in.)

When the connecting rods are installed without bearings, there should be no difference on side surface.

Piston

Clean piston.

(1)	Using a gasket scraper, remove the carbon from the piston top.

(2)	Using a groove cleaning tool or broken ring, clean the piston ring grooves.

(3)

Using solvent and a brush, thoroughly clean the piston.

Do not use a wire brush.

Check the piston-to-cylinder clearance by calculating the difference between the cylinder bore inner diameter and the piston outer diameter.

Piston-to-cylinder clearance :

0.025 - 0.045 mm (0.0010 - 0.0018 in.)

(1)

Using a cylinder bore gauge, measure the cylinder bore diameter at position in the thrust and axial direction.

Cylinder bore diameter :

72.00 - 72.03 mm (2.8346 - 2.8358 in.)

Measure at 5mm (0.1969 in.) / 71.5mm (2.8150 in.) / 132.5mm (5.2165 in.) from the top of the cylinder block.

(2)

Measure the piston outside diameter at 30 mm (1.1811 in) from top land of the piston.

Piston outside diameter :

71.965 - 71.995 mm (2.8333 - 2.8344 in.)

Select the piston matching with cylinder bore class.

Piston-to-cylinder clearance :

0.025 - 0.045 mm (0.0010 - 0.0018 in.)

(1)

Check the cylinder bore size code on the cylinder block side surface.

Cylinder Bore Inner Diameter

Size Code	Mark	Inside Diameter
a	A	71.00 - 71.01 mm (2.79528 - 2.79567 in.)
b	B	71.01 - 71.02 mm (2.79567 - 2.79606 in.)
c	C	71.02 - 71.03 mm (2.79606 - 2.79646 in.)

(2)

Check the piston size mark on the piston top face.

Piston Outer Diameter

Class		Inside Diameter
a	A	70.965 - 70.975 mm (2.79390 - 2.79429 in.)
b	B	70.975 - 70.985 mm (2.79429 - 2.79469 in.)
c	C	70.985 - 70.995 mm (2.79469 - 2.79508 in.)

Piston Rings

Inspect the piston ring side clearance.

Using a feeler gauge, measure the clearance between new piston ring and the wall of ring groove.

If the clearance is greater than maximum, replace the piston.

Piston ring side clearance :

[Standard]

No.1 ring :

0.05 - 0.08 mm (0.0020 - 0.0031 in.)

No.2 ring :

0.04 - 0.08 mm (0.0016 - 0.0031 in.)

Oil ring :

0.050 - 0.125 mm (0.0020 - 0.0049 in.)

If the clearance is greater than maximum, replace the piston.

Inspect piston ring end gap.

To measure the piston ring end gap, insert a piston ring into the cylinder bore. Position the ring at right angles to the cylinder wall by gently pressing it down with a piston. Measure the gap with a feeler gauge.

If the gap exceeds the service limit, replace the piston rings. If the gap is too large, recheck the cylinder bore inner diameter. If the bore is over the service limit, the cylinder block must be replaced.

Piston ring end gap :

[Standard]

No.1 ring: 0.13 - 0.18 mm (0.0051 - 0.0071 in.)

No.2 ring: 0.25 - 0.40 mm (0.0098 - 0.0157 in.)

Oil ring : 0.10 - 0.40 mm (0.0039 - 0.0157 in.)

Piston Pins

Measure the diameter of the piston pin.

Piston pin diameter :

17.997 - 18.000 mm (0.70854 - 0.70866 in.)

Measure the piston pin-to-piston clearance.

Piston pin-to-piston clearance :

0.005 - 0.012 mm (0.00020 - 0.00047 in.)

Check the clearance between the piston pin outer diameter and the connecting rod small end inner diameter.

Piston pin-to-connecting rod clearance :

0.005 - 0.014 mm (0.00002 - 0.00055 in.)

Reassembly

•	Thoroughly clean all parts to be assembled.

•	Before installing the parts, apply fresh engine oil to all sliding and rotating surfaces.

•	Replace all gaskets, O-rings and oil seals with new parts.

•	Always use new crankshaft main bearing cap bolts. Crankshaft main bearing cap bolts are toque-to-yield bolts designed to be permanently elongated beyond the state of elasticity when torqued, so if the bolts are removed and reused, it may cause the bolts to break or fail to maintain clamping force.

•	Always use new connecting rod cap bolts. Connecting rod cap bolts are toque-to-yield bolts designed to be permanently elongated beyond the state of elasticity when torqued, so if the bolts are removed and reused, it may cause the bolts to break or fail to maintain clamping force.

Assemble the piston and the connecting rod.

(1)	Install the snap ring (A) in one side of the piston pin hole.

(2)	Align the piston front mark (A) and the connecting rod front mark (B).

(3)	Insert the piston pin (A) into the piston pin hole and the small end bore of connecting rod.

(4)

Install the snap ring (B) to the other side after inserting the piston pin.

•	Apply a sufficient amount of engine oil to outer surface of the piston, inner surface of piston pin hole and small end bore of the connecting rod before inserting the piston pin.

•	Be careful not to damage and scratch the small end bore, piston pin hole and piston pin when inserting the piston pin.

•	Set the snap ring firmly so that the snap ring can contact with the whole groove of the piston pin hole.

Install the piston rings.

(1)	Install the oil ring spacer and 2 side rails by hand.

(2)	Using a piston ring expander, install the 2 compression rings with the maker mark facing upward.

(3)

Position the piston rings so that the ring ends are as shown. (The No.1 ring should be on the opposite side of the No.2 ring.)

Example)

Confirm that the oil ring turns smoothly.

Install the connecting rod bearings.

(1)	Align the bearing claw with the groove of the connecting rod or connecting rod cap.

(2)

Install the bearings (A) in the connecting rod and connecting rod cap (B).

Be careful not to change the position of bearing caps.

Install the piston and connecting rod assemblies.

•	Before installing the piston, apply a coat of engine oil to the ring grooves and cylinder bores.

•	Install the piston and connecting rod assembly with the front marks facing the front of the engine.

(1)	Install the ring compressor, check that the rings are securely in place, and then position the piston in the cylinder, and tap it in using the wooden handle of a hammer.

(2)	Stop after the ring compressor pops free, and check the connecting rod-to-crank journal alignment before pushing the piston into place.

(3)

Apply engine oil to the bolt threads. Install the rod caps with bearings, and tighten the bolts.

Tightening torque :

[10.8 - 14.7 N·m (1.1 - 1.5 kgf·m, 8.0 - 10.9 lb·ft)] + [88 - 92°]

Always use new connecting rod cap bolts. Connecting rod cap bolts are torque-to-yield bolts designed to be permanently elongated beyond the state of elasticity when torqued. Reusing the removed bolts can cause the bolts to break or fail to maintain clamping force.

5.	Check the connecting rod end play.

Install the ladder frame.

(1)	Clean the sealing face before assembling ladder frame and cylinder block.

(2)	Install the new O-ring (A) on the cylinder block.

(3)

Apply liquid sealant TB 1217H on the oil pan. Assemble the part within 5 minutes of applying sealant.

Bead width :

2.5 mm (0.098 in.) - 3.5 mm (0.138 in.)

Install the ladder frame (A).

Tightening torque :

18.6 - 23.5 N·m (1.9 - 2.4 kgf·m, 13.7 - 17.4 lb·ft)

8.	Assemble the remaining parts in the reverse order of disassembly.

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