1D-48 Engine Mechanical:
Valve Spring Inspection
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
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 kgf) for 31.50 mm
(23.6 – 27.6 lb/1.240 in.)
Limit: 102 N (10.2 kgf) for 31.50 mm (22.5 lb/1.240 in.)
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.)
Pistons, Piston Rings, Connecting Rods and
1. Top ring
2. 2nd ring
3. Oil ring
5. Connecting rod
6. Connecting rod bearing cap
7. Connecting rod bearing
8. Piston pin
9. Piston pin circlip
10. Bearing cap nut
: Tighten 15 N⋅m (1.5 kgf-m, 11.0 lb-ft), 45° and 45° by the specified
: Apply engine oil to sliding surface of each part.
: Do not reuse.
"A": Apply engine oil to sliding surface except inner surface of big end,
"B": Point arrow mark on cap to crankshaft pulley side.
"C": Do not apply oil between connecting rod and bearing or between
: See "A"
: See "B"
: See "C"
and rod bolts. Make sure rod bolt diameter when reuse it due to
plastic deformation tightening. Refer to "Piston Pins and Connecting
bearing cap and bearing.