Suzuki Grand Vitara JB416 / JB420. Manual - part 93

1D-40 Engine Mechanical: For M16A Engine with VVT

Cylinder Head Inspection

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• Remove all carbon deposits from combustion 

chambers.

NOTE
Do not use any sharp-edged tool to scrape 
off carbon deposits. Be careful not to scuff or 
nick metal surfaces when decarbonizing. The 
same applies to valves and valve seats, too.

 

• Check cylinder head for cracks on intake and exhaust 

ports, combustion chambers, and head surface. Using 
a straightedge and thickness gauge, check flatness of 
gasketed surface at a total of 6 locations. If distortion 
limit is exceeded, correct gasketed surface with a 
surface plate and abrasive paper of about #400 
(Waterproof silicon carbide abrasive paper): place 
abrasive paper on and over surface plate, and rub 
gasketed surface against paper to grind off high spots. 
Should this fail to reduce thickness gauge readings to 
within limit, replace cylinder head. 
Leakage of combustion gases from this gasketed joint 
is often due to warped gasketed surface: such 
leakage results in reduced power output.

Distortion for cylinder head surface on piston side
Limit: 0.03 mm (0.001 in.)

• Distortion of manifold seating faces: 

Check seating faces of cylinder head for manifolds, 
using a straightedge and thickness gauge, in order to 
determine whether these faces should be corrected or 
cylinder head replaced.

Distortion for cylinder head surface on intake and 
exhaust manifold
Limit: 0.05 mm (0.002 in.)

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Engine Mechanical: For M16A Engine with VVT 1D-41

Cylinder Head Bolt
Measure each thread diameter of cylinder head bolt (1) 
at “A” on 83.5 mm (2.81 in.) from seat side of flange bolt 
and “B” on 115 mm (4.53 in.) from seat side of flange bolt 
by using a micrometer (2).
Then calculate difference in diameters (“A” – “B”). If it 
exceeds limit, replace with new one.

Cylinder head bolt diameter measurement points
“a”: 83.5 mm (2.81 in.)
“b”: 115 mm (4.53 in.)

Cylinder head bolt diameter difference (deformation)
Limit (“A” – “B”): 0.1 mm (0.004 in.)

Valve Spring Inspection

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Valve Spring Free Length and Preload
Referring to data, check to be sure that each spring is in 
sound condition, free of any evidence of breakage or 
weakening. Remember, weakened valve springs can 
cause chatter, not to mention possibility of reducing 
power output due to gas leakage caused by decreased 
seating pressure.

Valve spring free length
Standard: 36.83 mm (1.450 in.)
Limit: 35.83 mm (1.411 in.)

Valve spring preload
Standard: 107 – 125 N (10.7 – 12.5 kg) for 31.50 mm 
(23.6 – 27.6 lb/1.240 in.)
Limit: 102 N (10.2 kg) for 31.50 mm (22.5 lb/1.240 in.)

Spring Squareness
Use a square and surface plate to check each spring for 
squareness in terms of clearance between end of valve 
spring and square. Valve springs found to exhibit a 
larger clearance than limit must be replaced.

Valve spring squareness
Limit: 1.6 mm (0.063 in.)

 

“A”

“a”

“b”

“B”

 

1

1

2

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1D-42 Engine Mechanical: For M16A Engine with VVT

Pistons, Piston Rings, Connecting Rods and Cylinders Components

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Pistons, Piston Rings, Connecting Rods and 
Cylinders Removal and Installation

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Removal

1) Remove engine assembly from vehicle referring to 

“Engine Assembly Removal and Installation: For 
M16A Engine with VVT”.

2) Remove cylinder head referring to “Valves and 

Cylinder Head Removal and Installation: For M16A 
Engine with VVT”.

3) Mark cylinder number on all pistons, connecting rods 

and connecting rod caps using silver pencil or quick 
drying paint.

4) Remove rod bearing caps.
5) Install guide hose (1) over threads of rod bolts.

This prevents damage to crank pin and rod bolt 
threads when removing connecting rod.

6) Decarbonize top of cylinder bore before removing 

piston from cylinder.

7) Push piston and connecting rod assembly out 

through the top of cylinder bore.

[A]: 1) Tighten all nuts to 15 N

⋅m (1.5 kgf-m).

2) Then retighten all nuts by turning through 45

°.

3) Repeat Step 2) again.

7. Connecting rod bearing

: See “C”

1. Top ring

8. Piston pin

2. 2nd ring

9. Piston pin circlip

3. Oil ring

10. Bearing cap nut

4. Piston

: Tightening torque

5. Connecting rod

: See “A”

: Apply engine oil to sliding surface of each part.

6. Connecting rod bearing cap

: See “B”

: Do not reuse.

“A”: Apply engine oil to sliding surface except inner surface of big end, and rod bolts.

Check rod bolt, plastic deformation tightening bolt, for deformation referring to “Connecting rod bolt deformation (Plastic deformation tightening bolt) under 
“Piston Pins and Connecting Rods Inspection: For M16A Engine with VVT”, if it is reused

“B”: Point arrow mark on cap to crankshaft pulley side.

“C”: Do not apply oil between connecting rod and bearing or between bearing cap and bearing.

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Engine Mechanical: For M16A Engine with VVT 1D-43

Installation

1) Apply engine oil to pistons, rings, cylinder walls, 

connecting rod bearings and crank pins.

NOTE
Do not apply oil between connecting rod and 
bearing or between bearing cap and bearing.

 

2) Install guide hoses (1) over connecting rod bolts.

These guide hoses protect crank pin and threads of 
rod bolt from damage during installation of 
connecting rod and piston assembly.

3) When installing piston and connecting rod assembly 

into cylinder bore, point front mark (1) on piston head 
to crankshaft pulley side.

4) Install piston and connecting rod assembly into 

cylinder bore. Use special tool (Piston ring 
compressor) to compress rings. Guide connecting 
rod into place on crankshaft.
Using a hammer handle, tap piston head to install 
piston into bore. Hold ring compressor firmly against 
cylinder block until all piston rings have entered 
cylinder bore.

Special tool
(A):  09916–77310

5) Install bearing cap (1):

Point arrow mark (2) on cap to crankshaft pulley 
side.
After applying engine oil to rod bolts and tighten cap 
nuts (3) gradually as follows.

NOTE
If connecting rod bolt is reused, make sure to 
check connecting rod bolt for deformation 
referring to “Connecting rod bolt deformation 
(Plastic deformation tightening bolt)” under 
“Piston Pins and Connecting Rods 
Inspection: For M16A Engine with VVT”.

 

a) Tighten all cap nuts to 15 N

⋅m (1.5 kgf-m, 11.0 lb-

ft).

b) Retighten them to 45

°

c) Repeat Step b) once again.

Tightening torque
Connecting rod bearing cap nut (a):  15 N

⋅m 

(1.5 kgf-m, 11.0 lb-ft) and then retighten by 
turning through 45

° twice

6) Install cylinder head referring to “Valves and Cylinder 

Head Removal and Installation: For M16A Engine 
with VVT”.

A: Crankshaft pulley side

B: Flywheel side

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