Mazda MX-5 Miata (1997+). Manual — part 60

3. Install main bearing caps with square mark facing front of engine. Tighten main bearing cap bolts in 2-3

step, working outward from center bearing. Tighten bolts to specification. See TORQUE
SPECIFICATIONS . Thrust Bearing - Install thrust bearing before installing crankshaft. Check
crankshaft end play with crankshaft bearings and caps installed, but without connecting rods attached to
crankshaft. DO NOT turn crankshaft until bearings are lubricated. If crankshaft end play exceeds
specification, grind crankshaft and replace thrust bearings with oversize thrust bearings, or replace
crankshaft and thrust bearings. See CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS
under ENGINE SPECIFICATIONS.

Cylinder Block

Check cylinder bore out-of-round, taper, ridge and piston-to-cylinder bore clearance. Check head gasket surface
for warpage. If warpage is not within specification, machine or replace cylinder block as necessary. See
CYLINDER BLOCK under ENGINE SPECIFICATIONS. Remove, clean and install oil jets for piston oil
spraying.

ENGINE OILING

ENGINE LUBRICATION SYSTEM

NOTE:

See cross-sectional view of engine oil circuit. See Fig. 21 .

1997 Mazda MX-5 Miata

1997-98 ENGINES 1.8L 4-Cylinder

Fig. 21: Cross-Sectional View Of Engine Oil Circuit
Courtesy of MAZDA MOTORS CORP.

Crankcase Capacity

See ENGINE OIL CRANKCASE CAPACITY .

Oil Pressure

With engine at operating temperature, oil pressure should be 15-28 psi (1.0-2.0 kg/cm

2

) at 1000 RPM, and 43-

57 psi(3.0-4.0 kg/cm

2

) at 3000 RPM.

Oil Pressure Relief Valve

Pressure relief valve opening pressure is 50-64 psi (3.5-4.5 kg/cm

2

). Pressure relief valve is located in oil pump

body and is not adjustable.

ENGINE OIL CRANKCASE CAPACITY

1997 Mazda MX-5 Miata

1997-98 ENGINES 1.8L 4-Cylinder

OIL PUMP

Removal & Disassembly

1. Disconnect negative battery cable. Remove dipstick, tube and "O" ring. Drain engine oil and coolant.

Remove drive belts, crankshaft and water pump pulleys. Remove generator, A/C compressor and
mounting bracket. Without disconnecting A/C hoses, secure A/C compressor away from engine. Remove
timing belt and related components. See TIMING BELT under REMOVAL & INSTALLATION.

2. Hold crankshaft sprocket in place and remove crankshaft sprocket bolt. Remove crankshaft sprocket

using steering wheel puller. Leave crankshaft Woodruff key in place.

3. Remove oil pan and oil pump pick-up tube. See OIL PAN under REMOVAL & INSTALLATION.

Remove oil pump housing assembly. Using a screwdriver protected with a rag, drive oil seal out from
inside of oil pump housing assembly.

4. Remove pump cover screws (use a manual impact screwdriver, if necessary). See Fig. 22 . Remove pump

cover. Note location of alignment marks on inner and outer rotors. Remove inner and outer rotors. To
remove pressure relief valve, remove spring seat, pressure spring and control plunger.

Inspection

Replace pressure relief valve spring if length is not as specified. See OIL PUMP SPECIFICATIONS . Ensure
plunger slides freely in bore. Replace oil pump housing assembly if clearances are not as specified. See OIL
PUMP SPECIFICATIONS .

Reassembly & Installation

1. Apply oil to friction surfaces. Install inner and outer rotors with marks aligned. See Fig. 23 . Install

pressure relief valve components. Apply oil to lip of NEW oil seal. Press oil seal into bore until even with
face of oil pump housing assembly.

2. Install pump cover. Tighten screws to 53-78 INCH lbs. (6-9 N.m). To complete installation, reverse

removal procedure. Tighten bolts to specification. See TORQUE SPECIFICATIONS .

OIL PUMP SPECIFICATIONS

Application

W/O Filter Qts. (L)

W/Filter Qts. (L)

Miata & Protege

3.8 (3.6)

4.0 (3.8)

Application

Maximum Clearance In. (mm)

Maximum Rotor Tip Clearance

(1)

.0079 (.20)

Maximum Rotor-To-Pump Body Clearance

(2)

.0079 (.20)

Maximum Rotor Side Clearance

(3)

.0055 (.14)

Pressure Relief Spring Free Length

1.809 (45.94)

(1)

See Fig. 23 .

(2)

Insert feeler gauge between outer rotor and pump body.

Place straightedge across pump body and check clearance between straightedge and both rotors.

1997 Mazda MX-5 Miata

1997-98 ENGINES 1.8L 4-Cylinder

Fig. 22: Exploded View Of Oil Pump
Courtesy of MAZDA MOTORS CORP.

(3)

1997 Mazda MX-5 Miata

1997-98 ENGINES 1.8L 4-Cylinder