Pistons, Piston Rings, Connecting Rods and Cylinders Inspection - Suzuki Jimny Workshop Manual
1D
Pistons, Piston Rings, Connecting Rods and Cylinders Inspection
Cylinders
•
Inspect cylinder walls for scratches, roughness or ridges which indicate excessive wear.
If cylinder bore is very rough, deeply scratched or ridged, replace cylinder block.
If cylinder bore is very rough, deeply scratched or ridged, replace cylinder block.
Pistons
•
Inspect piston for faults, cracks or other damaged.
Damaged or faulty piston should be replaced.
• Piston diameter:
As indicated in the figure, piston diameter should be measured at a position “a” from piston top in the direction perpendicular to piston pin.
Damaged or faulty piston should be replaced.
• Piston diameter:
As indicated in the figure, piston diameter should be measured at a position “a” from piston top in the direction perpendicular to piston pin.
Piston diameter specification:
75.938 – 75.952 mm (2.98969 – 2.99023 in.)
| “a”: | 56.0 mm (2.205 in.) |
Piston Pin
•
Check piston pin, connecting rod small end bore and piston bore for wear or damage, paying particular attention to condition of small end bore bush.
If pin, connecting rod small end bore or piston bore is badly worn or damaged, replace pin, connecting rod and/or piston.
• Piston pin clearance:
Check piston pin clearance in small end and piston.
Replace connecting rod and/or piston if its small-end is badly worn or damaged or if measured clearance out of specification.
If pin, connecting rod small end bore or piston bore is badly worn or damaged, replace pin, connecting rod and/or piston.
• Piston pin clearance:
Check piston pin clearance in small end and piston.
Replace connecting rod and/or piston if its small-end is badly worn or damaged or if measured clearance out of specification.
Clearance between small-end and piston pin:
0.013 – 0.030 mm (0.00052 – 0.00118 in.)
Small-end bore for connecting rod:
26.013 – 26.025 mm (1.02414 – 1.02460 in.)
Piston pin outside diameter:
25.995 – 26.000 mm (1.02343 – 1.02362 in.)
Piston Rings
•
Piston ring end gap
To measure end gap, insert piston ring (1) into cylinder bore and then measure the gap by using thickness gauge (2).
If measured gap is out of specification, replace ring.
•
Piston ring thickness
Measure piston ring thickness. If measured thickness is out of specification, replace piston ring.
•
Ring groove clearance
Before checking, piston grooves must be clean, dry and free of carbon.
Fit new piston ring (1) into piston groove, and measure clearance between ring and ring land by using thickness gauge (2).
If clearance is out of specification, replace piston.
To measure end gap, insert piston ring (1) into cylinder bore and then measure the gap by using thickness gauge (2).
If measured gap is out of specification, replace ring.
NOTE:
Decarbonize and clean top of cylinder bore before inserting piston ring.
Piston ring end gap
Top ring: 0.20 – 0.35 mm (0.0079 – 0.0137 in.)
2nd ring: 0.70 – 0.90 mm (0.0276 – 0.0354 in.)
Oil ring: 0.25 – 0.50 mm (0.0099 – 0.0196 in.)
Measure piston ring thickness. If measured thickness is out of specification, replace piston ring.
Piston ring thickness
Top ring: 1.97 – 1.99 mm (0.0776 – 0.0783 in.)
2nd ring: 1.97 – 1.99 mm (0.0776 – 0.0783 in.)
Oil ring: 2.47 – 2.49 mm (0.0973 – 0.0980 in.)
Before checking, piston grooves must be clean, dry and free of carbon.
Fit new piston ring (1) into piston groove, and measure clearance between ring and ring land by using thickness gauge (2).
If clearance is out of specification, replace piston.
Ring groove clearance
Top ring: 0.10 – 0.12 mm (0.0040 – 0.0047 in.)
2nd ring: 0.08 – 0.10 mm (0.0032 – 0.0039 in.)
Oil ring: 0.03 – 0.05 mm (0.0012 – 1.2700 in.)
Connecting Rod
•
Connecting rod big end bore and length.
a.
Install bearing cap (2) to connecting rod (1).
b. Measure connecting rod big end bore and length.
If measured bore and length is out of specification, replace connecting rod.
•
Connecting rod big end thrust play
b. Measure connecting rod big end bore and length.
If measured bore and length is out of specification, replace connecting rod.
Big end bore “a”:
47.610 – 47.628 mm (1.87441 – 1.87511 in.)
Connecting rod length “b”:
170.56 – 170.57 mm (6.7150 – 6.7153 in.)
a.
Install connecting rod referring to “Installation” under
Pistons, Piston Rings, Connecting Rods and Cylinders Removal and Installation:K9K
.
b. Check big-end of connecting rod for thrust play with rod fitted and connected to its crank pin in the normal manner. If measured thrust play is out of specification, replace connecting rod.
b. Check big-end of connecting rod for thrust play with rod fitted and connected to its crank pin in the normal manner. If measured thrust play is out of specification, replace connecting rod.
Connecting rod big end thrust play:
0.205 – 0.467 mm (0.00807 – 0.01838 in.)
Crank Pin and Connecting Rod Bearings
•
Inspect crank pin for uneven wear or damage. Measure crank pin for crank pin diameter using a micrometer. If crank pin is damaged or crank pin diameter is out of specification, replace crankshaft.
•
Rod bearing:
Inspect bearing shells for signs of fusion, pitting, burn or flaking and observe contact pattern. Bearing shells found in defective condition must be replaced.
•
Rod bearing clearance:
Crank pin diameter:
43.960 – 43.980 mm (1.73071 – 1.73150 in.)
Inspect bearing shells for signs of fusion, pitting, burn or flaking and observe contact pattern. Bearing shells found in defective condition must be replaced.
NOTE:
Do not rotate crankshaft while gauging plastic is installed.
a.
Before checking bearing clearance, clean bearing and crank pin.
b. Install bearing in connecting rod and bearing cap referring to “Reassembly” under Pistons, Piston Rings, Connecting Rods and Cylinders Disassembly and Reassembly:K9K .
c. Place a piece of gauging plastic (1) to full width of crank pin as contacted by bearing (parallel to crankshaft), avoiding oil hole.
d.
Install connecting rod and bearing cap referring to “Installation” under
Pistons, Piston Rings, Connecting Rods and Cylinders Removal and Installation:K9K
.
e. Using a scale (1) on gauging plastic (2) envelope, measure gauging plastic width at the widest point (clearance) after removing cap.
If clearance is out of specification, use a new bearing and remeasure clearance.
b. Install bearing in connecting rod and bearing cap referring to “Reassembly” under Pistons, Piston Rings, Connecting Rods and Cylinders Disassembly and Reassembly:K9K .
c. Place a piece of gauging plastic (1) to full width of crank pin as contacted by bearing (parallel to crankshaft), avoiding oil hole.
e. Using a scale (1) on gauging plastic (2) envelope, measure gauging plastic width at the widest point (clearance) after removing cap.
If clearance is out of specification, use a new bearing and remeasure clearance.
Connecting rod bearing clearance:
0.010 – 0.064 mm (0.0004 – 0.0025 in.)
Selection of Piston
1)
Install piston and connecting rod referring to “Installation” under
Pistons, Piston Rings, Connecting Rods and Cylinders Removal and Installation:K9K
.
2)
Using special tool and dial gauge, measure piston protrusion at specified measurement position (2) as shown in the figure when piston (1) reaches top dead center. Repeat this procedure with each piston.
If piston protrusion is out of specification, proceed to next step.
If piston protrusion is out of specification, proceed to next step.
Piston protrusion “a”:
0.030 – 0.288 mm (0.00119 – 0.01133 in.)
3)
Check connecting rod length referring to “Connecting Rod” under
Pistons, Piston Rings, Connecting Rods and Cylinders Inspection:K9K
.
If connecting rod is normal, proceed to next step.
If connecting rod is normal, proceed to next step.
4)
Replace piston (1) as follows in order to adjust piston protrusion to specified value.
a)
Remove piston, and measure the following specification.
•
Piston pin diameter “b”
• Distance “c” between top of piston and top of piston pin hole
• Distance “c” between top of piston and top of piston pin hole
b)
Obtain distance “d” between top of piston and center of piston pin hole by the following equation.
“d”= “b” / 2 + “c”
“d”= “b” / 2 + “c”
c)
Using measured piston protrusion “a” at Step 2), obtain adjusting distance “e” by the following equation.
“e” = “d” + 0.159 mm (0.0063 in.) – “a”
Example:
When distance “d” of removed piston is 41.620 mm (1.63858 in.), and measured piston protrusion “a” is 0.020 mm (0.0008 in.).
Calculated adjusting distance “e” = 41.620 mm (1.63858 in.) + 0.159 mm (0.0063 in.) – 0.020 mm (0.0008 in.) = 41.759 mm (1.64406 in.)
“e” = “d” + 0.159 mm (0.0063 in.) – “a”
When distance “d” of removed piston is 41.620 mm (1.63858 in.), and measured piston protrusion “a” is 0.020 mm (0.0008 in.).
Calculated adjusting distance “e” = 41.620 mm (1.63858 in.) + 0.159 mm (0.0063 in.) – 0.020 mm (0.0008 in.) = 41.759 mm (1.64406 in.)
d)
Select new piston so that distance “e” is within range of distance “d” of new piston.
Available new piston class
| Piston class (1) | Distance “d” |
| J |
41.605 – 41.645 mm
(1.63800 – 1.64122 in.) |
| K |
41.647 – 41.687 mm
(1.63965 – 1.64122 in.) |
| L |
41.689 – 41.729 mm
(1.64130 – 1.64287 in.) |
| M |
41.731 – 41.771 mm
(1.64296 – 1.64452 in.) |
| N |
41.773 – 41.813 mm
(1.64461 – 1.64618 in.) |
NOTE:
•
Piston class (1) is marked on piston top as shown in the figure.
• Supplied piston is only K, L and M classes.
If selected piston is J class, K class piston must be installed as a replacement.
If selected piston is N class, M class piston must be installed as a replacement.
• Supplied piston is only K, L and M classes.
If selected piston is J class, K class piston must be installed as a replacement.
If selected piston is N class, M class piston must be installed as a replacement.
e)
Replace removed piston to selected piston.
f)
Check piston protrusion, again.