1997 MAZDA MX-5 engine

Valves
Check valve face angle, head diameter, margin thickness and stem diameter. Service or replace valves if
measurements are not within specifications. See VALVES & VALVE SPRINGS
under ENGINE
SPECIFICATIONS.
Valve Seat Correction Angles
Measure seat contact width on valve. See VALVE SEAT. If seat width is not within specification or if valve
face does not contact center of valve seat, correct seat using a 70-degree grinding stone. After correcting seat,
lightly finish seat with 45-degree grinding stone.
VALVE TRAIN
Hydraulic Lash Adjusters
1. Remove camshaft cover. Check movement of each Hydraulic Lash Adjuster (HLA) by pushing
downward using hand pressure only. If HLA compresses, replace HLA. To remove HLA, remove
camshafts. See CAMSHAFT
under REMOVAL & INSTALLATION. Mark location of HLA before
removing from bore. Lift HLA from cylinder head.
2. Inspect HLA friction surfaces for wear and damage. Replace HLA if required. Coat HLA with engine oil
and install in original location. Ensure HLA moves smoothly in bore by using small magnet attached to
HLA.
CYLINDER BLOCK ASSEMBLY
Piston & Connecting Rod Assembly
1. Before removing rod cap from crankshaft, measure and record rod side play. See CONNECTING RODS
under ENGINE SPECIFICATIONS. Before removing connecting rods, measure and record connecting
rod bearing oil clearance. See CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS
under
ENGINE SPECIFICATIONS.
2. Before separating piston from connecting rod, mark piston in relation to connecting rod. Check
oscillation movement of piston and rod assembly (hold piston horizontally, lift rod and allow rod to drop
by its own weight). If pin binds in pin bore (rod does not drop), replace piston and/or pin as necessary.
3. To separate components, press piston pin out of piston and rod assembl
y, noting pressure required to
Normal1.772-1.791 (45.00-45.50)
Serviceable1.733-1.772 (45.60-46.50)
NOTE: If hydraulic lash adjusters are persistently noisy, check with manufacturer
for availability of modified adjusters.
NOTE: During disassembly, match mark components for reassembly reference.

1997 Mazda MX-5 Miata
1997-98 ENGINES 1.8L 4-Cylinder
Microsoft
Sunday, July 05, 2009 1:55:15 PMPage 27 © 2005 Mitchell Repair Information Company, LLC.

remove piston pin. If piston pin can be pressed out with less than 1100 lbs. (500 kg) of pressure, replace
piston and/or connecting rod.
4. Ensure piston pin diameter, piston fit and rod fit are within specification. See PISTONS, PINS &
RINGS under ENGINE SPECIFICATIONS. Using 1100-3300 lbs. (500-1500 kg) of pressure, install
piston pin through side of piston that has an "F" mark near pin bore. See Fig. 18
. Install piston and rod
assembly so "F" mark on side of piston is facing front of engine.
Fig. 18: Installing Piston & Connecting Rod Assembly

Courtesy of MAZDA MOTORS CORP.

1997 Mazda MX-5 Miata
1997-98 ENGINES 1.8L 4-Cylinder
Microsoft
Sunday, July 05, 2009 1:55:15 PMPage 28 © 2005 Mitchell Repair Information Company, LLC.

Fitting Pistons
1. Ensure pistons are not scored or damaged. Measure piston diameter on piston skirt at 90-degree angle
from piston pin, .65" (16.5 mm) below lowest ring groove. See PISTONS, PINS & RINGS
under
ENGINE SPECIFICATIONS.
2. Check piston-to-cylinder wall clearance in 3 different vertical places of piston travel. If clearance is not
within specification, re-bore cylinders to fit oversize pistons. Using NEW piston rings, measure piston
ring side clearance around entire piston circumference. If clearance is not within specification, replace
piston. See PISTONS, PINS & RINGS
.
Piston Rings
1. If ring end gap and side clearance are not within specification, replace piston and/or rings as necessary.
See PISTONS, PINS & RINGS
under ENGINE SPECIFICATIONS.
2. Install oil ring spacer. Ensure ends DO NOT overlap. See Fig. 19
. Upper and lower rails are the same
and are interchangeable. In stall rails, ensuring rails are expanded by spacer tangs (oil rings when
assembled should rotate freely). Install rings No. 1 (top) and No. 2 (second) with "R" mark toward top of
piston. Ensure ring end gaps are properly positioned around piston. See Fig. 20
.
Fig. 19: Identifying Oil Rings
NOTE: Pistons and rings are available in .010" (.25 mm) and .020" (.50 mm) oversize.

1997 Mazda MX-5 Miata
1997-98 ENGINES 1.8L 4-Cylinder
Microsoft
Sunday, July 05, 2009 1:55:15 PMPage 29 © 2005 Mitchell Repair Information Company, LLC.

Courtesy of MAZDA MOTORS CORP.
Fig. 20: Identifying Piston Rings & Positioning Ring End Gaps

Courtesy of MAZDA MOTORS CORP.
Crankshaft & Main Bearings
1. Check crankshaft connecting rod journals for wear, out-of-round, taper and undersize. Machine or replace
crankshaft and/or bearings as necessary. See CRANKSHAFT, MAIN & CONNECTING ROD
BEARINGS under ENGINE SPECIFICATIONS.
2. Before removing main cap, measure and record crankshaft end play by prying crankshaft forward, then
rearward. Using Plastigage method, measure and record main bearing oil clearance. Remove crankshaft.
Measure and record each main journal diameter in 2 places. See CRANKSHAFT, MAIN &
CONNECTING ROD BEARINGS under ENGINE SPECIFICATIONS.

1997 Mazda MX-5 Miata
1997-98 ENGINES 1.8L 4-Cylinder
Microsoft
Sunday, July 05, 2009 1:55:15 PMPage 30 © 2005 Mitchell Repair Information Company, LLC.

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
Microsoft
Sunday, July 05, 2009 1:55:15 PMPage 31 © 2005 Mitchell Repair Information Company, LLC.

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/cm2 ) 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/cm2). 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
Microsoft
Sunday, July 05, 2009 1:55:15 PMPage 32 © 2005 Mitchell Repair Information Company, LLC.

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
ApplicationW/O Filter Qts. (L)W/Filter Qts. (L)
Miata & Protege3.8 (3.6)4.0 (3.8)
ApplicationMaximum 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 Length1.809 (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
Microsoft
Sunday, July 05, 2009 1:55:15 PMPage 33 © 2005 Mitchell Repair Information Company, LLC.

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
Microsoft
Sunday, July 05, 2009 1:55:15 PMPage 34 © 2005 Mitchell Repair Information Company, LLC.