1997-98 ENGINES
1.8L 4-Cylinder
ENGINE IDENTIFICATION
Engines can be identified by engine model and number. See ENGINE IDENTIFICATION CODE. On Miata,
engine model and number are stamped on flange at upper right rear of cylinder block deck, as viewed from
flywheel. On Protege, engine model and number are stamped on flange at upper left rear of cylinder block deck,
as viewed from flywheel.
ENGINE IDENTIFICATION CODE
ADJUSTMENTS
VALVE CLEARANCE ADJUSTMENT
REMOVAL & INSTALLATION
FUEL PRESSURE RELEASE & PRIMING
Releasing Pressure (Miata)
Locate and remove fuel pump relay from under left side of dash, near steering column. Start engine and allow to
stall. After engine stalls, attempt to restart engine to ensure no residual pressure exists. Turn ignition off and
reinstall fuel pump relay. When disconnecting fuel hoses, cover connection with shop rag to catch fuel leakage.
To avoid excessive cranking after servicing, prime fuel system before starting engine.
Releasing Pressure (Protege)
NOTE: For repair procedures not covered in this article, see ENGINE OVERHAUL
PROCEDURES article in GENERAL INFORMATION.
ApplicationCode
Miata & Protege (1.8L DOHC)BP
NOTE: Valve clearance is not adjustable. Some Hydraulic Lash Adjuster (HLA) noise
may occur during engine start-up. Noise should disappear after engine reaches
normal operating temperature. If noise persists and oil level is okay, change
engine oil. If oil change does not reduce noise, check with manufacturer for
modified HLA.
NOTE: For reassembly reference, label all electrical connectors, vacuum hoses and
fuel lines before removal. Also place mating marks on engine hood and other
major assemblies before removal.
1997 Mazda MX-5 Miata
1997-98 ENGINES 1.8L 4-Cylinder
1997 Mazda MX-5 Miata
1997-98 ENGINES 1.8L 4-Cylinder
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differential housing block.
2. Tighten PPF/differential mounting spacer bolts to 28-38 ft. lbs. (38-52 N.m). See Fig. 4
. Install PPF to
differential. Hand-tighten long bolts. Ensure PPF-to-differential large shank reamer bolt and spacer are
properly installed.
3. When PPF is properly aligned between transmission and differential, tighten all long mounting bolts to
specification. Install rear transmission-to-PPF bracket and tighten to specification. See TORQUE
SPECIFICATIONS . To complete installation, reverse removal procedure. Before installing M/T shift
lever, add gear oil to transmission through shifter hole. Fill all fluids to correct level. Prime fuel system
before attempting to start engine. See FUEL PRESSURE RELEASE & PRIMING. Bleed cooling system.
See COOLING SYSTEM BLEEDING.
Fig. 4: Locating PPF
-To-Differential Reamer Bolt, Sleeve & Spacer
NOTE: Reamer bolt is the front long bolt attaching PPF to differential. This bolt
aligns PPF with drive train.
1997 Mazda MX-5 Miata
1997-98 ENGINES 1.8L 4-Cylinder
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2. Disconnect throttle cable. Remove fuel lines from fuel rail and pressure regulator. Remove throttle body
intake duct housing and throttle body. Remove by-pass air control valve and solenoid valves. Remove
upper intake manifold (if equipped).
3. Remove intake manifold support bracket from underneath manifold. Disconnect injector harness
connectors, and remove injectors/fuel rail assembly. Remove intake manifold and gasket.
Installation
1. Ensure all gasket surfaces are clean and flat. Using NEW gasket, install intake manifold to cylinder head.
Tighten manifold bolts/nuts evenly to specification, starting from center bolt and alternating outward. See
TORQUE SPECIFICATIONS
. Install support bracket underneath intake manifold.
2. Install gasket and upper intake manifold (if equipped). Tighten bolts/nuts evenly to specification,
alternating from top to bottom. See TORQUE SPECIFICATIONS
.
3. To complete installation, reverse removal procedure. Ensure throttle cable has .04-.12" (1-3 mm) free
play. Ensure injectors twist freely and are not cocked in insulator "O" rings. Refill engine with coolant.
EXHAUST MANIFOLD
Removal & Installation
1. Remove air cleaner intake duct from top of radiator/fan assembly (if equipped). Disconnect oxygen
sensor. Remove heat shields. Disconnect down pipe from exhaust manifold. Remove exhaust manifold.
2. To install, reverse removal procedure. Ensure all mating surfaces are clean and flat. Install NEW exhaust
manifold gasket to cylinder head. Tighten manifold bolts evenly to specification, starting from center bolt
and alternating outward. See TORQUE SPECIFICATIONS
.
CYLINDER HEAD
Removal
1. Release residual pressure from fuel system. See FUEL PRESSURE RELEASE & PRIMING . Drain
engine coolant. Note locations and disconnect all necessary electrical connectors, ground wires, vacuum
hoses, fuel hoses, coolant hoses and control cables for cylinder head removal. Plug all fuel hoses to avoid
leakage.
2. Remove spark plug wires from spark plugs. Remove all drive belts. Remove water pump pulley. Remove
timing belt. See TIMING BELT
. Remove camshaft/rocker cover.
3. Remove front exhaust pipe. Remove intake manifold support bracket. Loosen all cylinder head bolts
evenly, in 3 steps, in reverse of tightening sequence. See Fig. 7
. Remove bolts and cylinder head
assembly.
Inspection
Carefully clean carbon and gasket material from all mating surfaces. Clean threads of cylinder head bolts. Use a
tap to clean threads in engine block. Check cylinder head for warpage. Resurface or replace head if it is not
within specification. Check valve train components. Replace or resurface components if they are not within
1997 Mazda MX-5 Miata
1997-98 ENGINES 1.8L 4-Cylinder
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specification. See CYLINDER HEAD and VALVES & VALVE SPRINGS tables under ENGINE
SPECIFICATIONS .
Installation
Install cylinder head gasket, cylinder head assembly and bolts. Tighten cylinder head bolts in 2 steps, and in
sequence, to specification. See Fig. 7
. See TORQUE SPECIFICATIONS . To complete installation, reverse
removal procedure.
Fig. 7: Cylinder Head Bolt Tightening Sequence
Courtesy of MAZDA MOTORS CORP.
CRANKSHAFT FRONT SEAL
Removal
Disconnect negative battery cable. Remove drive belts and crankshaft pulley. Remove water pump pulley,
timing belt covers and timing belt. See TIMING BELT
. Use Crankshaft Lock Tool (49-D011-102) to lock
crankshaft sprocket into position. Remove crankshaft sprocket bolt. Remove crankshaft sprocket usin
g steering
1997 Mazda MX-5 Miata
1997-98 ENGINES 1.8L 4-Cylinder
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wheel puller. Pry out seal.
Installation
1. Apply light oil coat to seal lip. Using a hammer and seal installer, tap seal into oil pump body until it is
flush with edge of pump body. DO NOT bottom seal in pump body. Align keyway slots, and install
crankshaft sprocket and Woodruff key with tapered side toward oil pump body. Install crankshaft
sprocket bolt.
2. Using Crankshaft Lock Tool (49-D011-102), lock crankshaft sprocket into position. Tighten lock bolt to
specification. See TORQUE SPECIFICATIONS
.
3. Install timing belt. See TIMING BELT
under REMOVAL & INSTALLATION. Install timing belt
covers, pulleys and drive belts. Reconnect negative battery cable and ensure timing is correct.
TIMING BELT
Removal (Miata)
1. Disconnect negative battery cable. Drain cooling system. Remove radiator hose and by-pass hoses from
thermostat housing. Remove air cleaner intake duct assembly from between throttle body and air cleaner
filter housing.
2. Remove drive belts and water pump pulley. Align crankshaft pulley timing mark with cylinder No. 1 at
TDC of compression stroke. Hold crankshaft pulley stationary. Remove crankshaft pulley bolts and
pulley. Remove crankshaft pulley hub bolt and hub.
3. Remove cylinder head cover. Remove upper, center and lower timing belt cover. If timing belt is to be
reused, mark timing belt rotation direction. Ensure timing marks on camshaft sprockets are aligned. See
Fig. 8
. Loosen timing belt tensioner lock bolt, and move tensioner away from belt with spring fully
expanded. Remove timing belt.
Removal (Protege)
1. Disconnect negative battery cable. Raise and support vehicle. Remove right front wheel. Remove right
side cover and undercover.
2. Remove drive belts and water pump pulley. Align crankshaft pulley timing mark with cylinder No. 1 at
TDC of compression stroke. Hold crankshaft stationary. Remove crankshaft pulley bolts and pulley.
Remove crankshaft pulley hub bolt and hub.
3. Remove cylinder head cover. Remove upper, center and lower timing belt cover. If timing belt is to be
reused, mark timing belt rotation direction. Ensure timing marks on camshaft sprockets are aligned. See
Fig. 8
. Loosen timing belt tensioner lock bolt, and move tensioner away from belt with spring fully
expanded. Remove timin
g belt. NOTE: For 1997-98 vehicles, the manufacturer recommends the belt be replaced at
60,000 mile intervals for vehicles sold outside of California and Massachusetts.
For vehicles sold in California and Massachusetts, inspect timing belt at 60,000
and 90,000 miles, and replace timing belt at 105,000 miles.
1997 Mazda MX-5 Miata
1997-98 ENGINES 1.8L 4-Cylinder
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Inspection (All Models)
Check timing belt for cracks, peeling, abrasion or other damage. Check tensioner bearing for looseness or
roughness of rotation. Inspect tensioner spring for stretching. Replace parts as necessary.
Installation (All Models)
1. Position notch on crankshaft sprocket to 12 o'clock position (aligned with mark on oil pump). Align
timing marks on camshaft sprockets. See Fig. 8
. Ensure crankshaft timing mark is at TDC. Install belt
around crankshaft sprocket, then working in a counterclockwise direction, route belt around camshaft
sprockets.
2. Loosen timing belt tensioner lock bolt and allow spring to apply tension on belt. Snug tensioner lock bolt.
Rotate crankshaft 2 complete turns in direction of normal engine rotation. Ensure timing marks align. If
timing marks are not aligned, remove belt, realign all timing marks, and repeat installation procedure.
3. Check timing belt deflection with 22 lbs. (10 kg) of pressure applied to belt. See Fig. 9
. Ensure timing
belt deflection is within specification. See TIMING BELT DEFLECTION
.
TIMING BELT DEFLECTION
Application(1) Deflection In. (mm)
Miata & Protege.35-.45 (9.0-11.5)
(1)Deflection measurement is with 22 lbs. (10 kg) of pressure applied to timing belt. See Fig. 9 .
1997 Mazda MX-5 Miata
1997-98 ENGINES 1.8L 4-Cylinder
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Fig. 13: Camshaft Bearing Cap Bolt Removal & Installation Sequence (Protege) Installation
Courtesy of MAZDA MOTORS CORP.
CRANKSHAFT REAR OIL SEAL
Removal & Installation
1. Disconnect negative battery cable. Remove transmission/transaxle and flywheel. For automatic
transmission removal procedure, see REMOVAL & INSTALLATION article in TRANSMISSION
SERVICING. For manual transmission removal procedure, see appropriate article in CLUTCHES. On all
models, pry out rear oil seal.
2. To install, apply light coat of oil to seal lip and push seal over crankshaft. Tap seal into rear cover until it
is flush with edge of rear cover. DO NOT bottom seal in cover.
3. Completely remove used sealant from flywheel bolts. Apply lock-type sealant to bolts and install
flywheel to crankshaft. Tighten bolts to 71-76 ft. lbs. (96-103 N.m) in a star-pattern sequence. Install
clutch assembly (if equipped) and tighten cover bolts to 13-20 ft. lbs. (18-26 N.m) in a star-pattern
sequence. Install transmission/transaxle. See appropriate article in TRANSMISSION SERVICING or
CLUTCHES.
WATER PUMP
Removal & Installation
1997 Mazda MX-5 Miata
1997-98 ENGINES 1.8L 4-Cylinder
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1. Drain engine coolant. Disconnect battery cable. Position No. 1 cylinder at TDC of compression stroke.
On Protege, remove right side cover and undercover.
2. On Miata, remove air cleaner intake duct from between throttle body and air cleaner/filter assembly. On
all models, remove upper radiator hose and by-pass hoses from thermostat housing.
3. Remove drive belts and water pump pulley. Remove power steering pump with hoses attached and secure
pump away from engine (if necessary). Remove timing belt, tensioner and idler. See TIMING BELT.
4. Unbolt water inlet pipe from water pump. Water pump inlet pipe has lower radiator hose and by-pass pipe
attached to it. Remove bolts from water pump. To install, reverse removal procedure. Tighten bolt to
specification. See TORQUE SPECIFICATIONS
.
OIL PAN
Removal & Installation (Miata)
1. Disconnect negative battery cable. Drain engine oil. Remove dipstick, tube and "O" ring. Raise vehicle on
hoist. Remove engine undercover. Disconnect steering column shaft at steering rack coupling. See Fig.
14 . Remove engine mount nuts. Lift and support engine using jack.
2. Support crossmember using transmission jack and remove crossmember bolts. Slowly and carefully lower
crossmember until clearance between oil pan and steering rack is about 4 inches. Remove oil pan bolts
from engine block and transmission.
3. DO NOT damage sealant contact surfaces. Remove oil pan by prying between oil pan and transmission
support. Remove oil pan baffle by prying it from engine. See Fig. 14
. DO NOT deform oil pan baffle.
Replace oil pan baffle if deformed. Clean sealant from oil pan, bolts, engine block and both sides of oil
pan baffle.
4. To install, apply oil resistant sealant to engine block and oil pan. Install oil pan baffle and oil pan within 5
minutes of applying sealant. To complete installation, reverse removal procedure. Tighten bolts to
specification. See TORQUE SPECIFICATIONS
. Fill engine with oil to specification. See ENGINE
LUBRICATION SYSTEM under ENGINE OILING. NOTE: For further information on cooling systems, see SPECIFICATIONS & ELECTRIC
COOLING FANS article in ENGINE COOLING.
NOTE: On Miata, engine must be supported in order to remove oil pan.
1997 Mazda MX-5 Miata
1997-98 ENGINES 1.8L 4-Cylinder
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