MX-5 NA/NB Torque & Assembly Specs

By March 19, 2021
1 Comment

After detonating my motor (’99 1.8l) on the Autobahn at 180kph (~112 mph) due to a failed oil pump, I decided to go ahead and do the full rebuild myself. I was a bit nervous that I was in over my head, as it was my first-ever engine rebuild without any external support (other than the machine shop). However, I found a VVT motor out of a 2004 NBFL with only 65,000km and figured I would try my hand.

I mated my ’99 head onto the ’04 block, gained a little bit of compression, and will be full send here soon. I downloaded every manual and document that I find across the internet related to rebuilding a Miata motor, but the problem was that all these specifications and torque values were spread across multiple web-pages and were not contained to one source.

So, here all the values I could find for the NA/NB/NBFL combined onto a single webpage. I am not responsible for any that are incorrect, but I believe these to be accurate – we will see when I make another motor go BOOM.

Please feel free to send me any additional specs that you would like to see added – Zak@theapexdrag.com

Common Tune-up / Maintenance Items

ItemFoot/LBSNewton/MetersApplicable Notes
Differential Drain Plug (24mm)29-3939-53
Differential Fill Plug (23mm)29-3939-53
Engine Oil Drain Plug (19mm)22-3031-41
Gearbox Check/Fill Plug (9/16 Square)19-2825-39
Manual Gearbox Drain Plug (24mm)29-4340-58
Spark Plugs11-17 (132-204 inch/lbs)15-22*NOTE: 1/3 less if using anti-seize)
Wheel Lugs66-8689-117

Body

ItemFoot/LBSNewton/Meters
Door Hinge Bolts16-2222-30
Door Lock Striker14-1918-26
Door Wedge38-54 inch/lbs4.3-6.1
Hood Hinge14-1819-25
Trunk Lid Hinge Nuts70-95 inch/lbs8-10

Brakes

ItemFoot/LBSNewton/Meters
ABS Wheel Speed Sensor15-1819-25
Brake Line to Master Cylinder9.4-1613-22
Caliper Banjo Bolt16-2222-29
Caliper Mounting Bolts, Front36-5149-69
Caliper Mounting Bolts, Rear34-4946-66
Caliper Slide Pin, Front-Lower58-6578-88
Caliper Slide Pin, Front-Upper33-4045-54
Caliper Slide Pin, Rear-Lower25-2934-39
Caliper Slide Pin, Rear-Upper33-3645-49
Front Brake Bleeder53-78 inch/lbs5.9-8.8
Front/Rear Banjo Bolts16-2222-29
Master Cylinder to Booster7.2-119.8-16
Parking Brake Level Mounting Bolt14-199-26.0
Rear Adjuster Plug Bolt9-12.012-16.0
Rear Brake Bleeder53-86 inch/lbs5.9-9.8
Rear E-Brake Cable12-17.016-23
Rear Lock Bolt25-2934-39

Clutch Master and Slave

ItemFoot/LBSNewton/Meters
Master Pipe113-190 inch/lbs12.8-21.5
Slave Bleeder53-78 inch/lbs5.9-8.8
Slave Mount Bolt12-16.016-22.0
Slave Pipe113-190 inch/lbs12.8-21.5
Master Mount Nut14-1819-25

Drive Train (Differential)

ItemFoot/LBSNewton/Meters
Companion Flange Locknut87-130118-176
Differential Bearing Cap28-3838-51
Differential Carrier to Case17-1923-26
Differential Lock Plates14-1818-25
Differential Ring Gear51-6169-83
Power Plant Frame Bolts (Torque Arm)77-91104-123
Propeller Shaft Nuts (Drive Shaft)37-4350-58

Drive Train (Transmission)

ItemFoot/LBSNewton/Meters
Auto Trans Front Cover Bolts14-1819-24
Bell Housing Bolts48-6564-89
Clutch Bleeder Screw53-78 inch/lbs5.9-8.8
Flywheel Bolts (FSM - Thread Locker)71-7597-102
Power Plant Frame Bolts (Torque Arm)77-91104-123
Pressure Plate Bolts14-1918-26
Slave Cylinder Fluid Tube113-190 inch/lbs13-21
Slave Cylinder Mounting Bolts12-16.016-22
Starter Motor Bolts28-3838-51
Starter Motor Mounting Bracket Bolts28-3838-51
Starter Power Cable Nut87-95 inch/lbs9.8-10.7
Starter Rear to Bracket12-16.016-22

Engine (Cooling / Timing Belts / Belts)

ItemFoot/LBSNewton/MetersApplicable Notes
AC Compressor Bracket 1 Bolt Through Front14-1819-25
AC Compressor Bracket 4 Bolts to Block27-3837-52
AC Compressor Manifold Bolts8-11.010-15
AC Compressor Mounting Bolts11-15.015-21
Alternator Mounting Bolt (Pivot Bolt)27-3837-52
Alternator Tension Locking Bolt14-1919-25
Cam Cover Bolts (AKA Valve Cover)44-78 inch/lbs5-8.8*NOTE: Use Sequence for Torquing
Cam Sprocket Bolts37-4450-60
Crank Dampner Pulley Bolts (10mm - 4x)109-151 inch/lbs13-17
Crank Pulley Bolt116-122 (with Loctite 242-blue)157-165 (with Loctite 242-blue)
Cylinder Head Bolts56-6076-81*NOTE: Torque in stages and in order
Fan Housing to Radiator70-95 inch/lbs8-10.0
Radiator - Upper Bolts14-1819-25
Seal Plate Bolts (Timing Plate Behind Cam Cogs)70-95 inch/lbs8-10
Thermostat Cover - 2 Bolts14-1819-25
Thermostat Extension to Block14-1819-25
Timing Belt Cover Bolts70-95 inch/lbs8-10
Timing Belt Tensioner & Idler Pulley Bolt23-3838-51
Water Inlet Pipe - 2 Bolts to Water Pump14-1819-25
Water Pump - 4 Bolts to Block14-1819-25
Water Pump Pulley to Water Pump70-95 inch/lbs8-10

Engine (Internal)

ItemFoot/LBSNewton/Meters
Cam Bearing Caps100-125 inch/lbs11.3-14.2
Connecting Rod Cap Bolt35-3648-50
Head Bolt56-6071-81
Main Bearing Cap Bolt40-4354-58
Oil Jet105-156 inch/lbs11.8-17.6
Oil Pan to Block70-95 inch/lbs8-10
Oil Pump to Block14-1819-25
Oil Strainer70-85 inch/lbs (with Loctite Blue)8-10
Rear Main Seal Cover70-95 inch/lbs8-10

Engine (Miscellaneous)

ItemFoot/LBSNewton/Meters
Alternator Bracket to Block48-6564-89
Alternator (internal) 4x Assembly Bolts27-56 inch/lbs
Alternator (internal) Regulator Screws18-47 inch/lbs
Alternator Output Nut53-86 inch/lbs
Cam Angle Sensor (CAS) Adjustment Bolt*Snug*
Coil Bracket14-1819-25
Engine Hanger28-3838-51
Motor Mount Bracket to Block28-3838-51
Motor Mount Nuts42-5757-78
Oil Cooler Nut22-2830-39
Oil Dip Tube Bracket70-95 inch/lbs7.9-10.7
Oil Sender105-156 inch/lbs (with sealant)11.8-17.6
Power Steering Bracket to Block28-3838-51
Rear Water Outlet14-1819-25
Water Inlet Pipe Casting to Water Pump14-1819-25

Exhaust

ItemFoot/LBSNewton/Meters
Catalytic Converter Nuts28-3838-51
Exhaust Header Nuts29-3339-46
Exhaust Pipe Clamp Bolt (to Bell Housing)14-1819-25
Manifold Heat Sheild70-95 inch/lbs8-10
O2 Sensor22-36, but by feel normally

Intake

ItemFoot/LBSNewton/Meters
Air Box to Body14-1819-25
Airflow Meter or MAF Bolts70-95 inch/lbs8-10
EGR14-1819-25
Fuel Rail14-1819-25
Intake Manifold 12mm Bolts14-1819-25
Intake Manifold Support Braket28-3838-51
Throttle Body to Manifold14-1819-25

Interior

ItemFoot/LBSNewton/Meters
Convertible Latch Bolt37-55 inch/lbs4.3-6.2
Latch Strike Bolts87-130 inch/lbs10-15
Seat Belt Brace29-3739-50
Seat Belt Buckle29-5739-78
Seat Belt Retractor29-5739-78
Seat Belt to Floor29-5739-78
Seat Belt to Tower29-5739-78
Seat Hinge26-4135-55
Seat Track to Floor29-3739-50

Steering

ItemFoot/LBSNewton/MetersApplicable Notes
Inner Tie Rod Nut58-7279-98
Key Interlock38-54 inch/lbs4.2-6.1
Outer Tie Rod Nut on Rack Shaft26-2835-39
Outer Tie Rod Spindle (Castellated Nut)22-3330-44*NOTE: Start at 22, then tighten until cotten pin lines up
Rack to Frame34-4347-58
Steering Column to Dash12-1616-22
Steering Column to Firewall14-1918-26
Steering Pump Adjuster to Engine Bracket27-3937-53
Steering Pump Adjustment Lock Bolt14-1819-25
Steering Pump Pivot Bolt27-3937-53
Steering Pump Pressure Pipe Bracket13-1918-26
Steering Pump Pressure Union24-3432-47
Steering Shaft to Rack14-1918-26
Steering Shaft U-Joint13-2018-26
Steering Wheel29-3640-49

Suspension, Front

ItemFoot/LBSNewton/Meters
Axle Nut123-159167-215
Camber Bolts54-7073-95
Lower Ball Joint Castellated Nut42-5757-77
Lower Ball Joint, Horizontal54-6873-93
Lower Ball Joint Short Bolt54-6873-93
Shock Absorber Lower Bolt54-6873-93
Shock Absorber Plate22-2630-36
Shock Absorber Shaft24-3332-46
Sway Bar Bushing Bolts14-1918-26
Sway Bar Link Bolts27-3937-53
Upper Ball Joint Castellated Nut31-4442-60
Upper Control Arm Long Bolt87-101118-137

Suspension, Rear

ItemFoot/LBSNewton/Meters
Axle Nut160-216216-294
Camber Bolts54-7073-95
LCA Outer Long Bolt47-5463-74
Shock Absorber Bolt, Lower27-3937-53
Shock Absorber Shaft24-3332-46
Shock Absorber, Upper Plate22-2630-36
Subframe Brace41-5955-80
Sway Bar Bushing15-2020-28
Sway Bar Link27-3937-53
UCA Inner Bolts34-4947-66
UCA Outer Bolt34-4947-66

Engine Assembly Specifications

ItemInchesMillimeters
Camshaft End Play (min).008.20
Camshaft End Play (standard).0028-.0074 .07-.19
Camshaft Journal Diameter1.0213-1.0222 25.940-25.965
Camshaft Journal Oil Clearance (min).006 .15
Camshaft Journal Oil Clearance (standard).0014-.0031 .035-.081
Camshaft Journal Out Of Round (max).0012 .03
Camshaft Lobe Height, Exhaust (min)1.7480 44.400
Camshaft Lobe Height, Exhaust (standard)1.7559 44.600
Camshaft Lobe Height, Intake (min)1.728143.894
Camshaft Lobe Height, Intake (standard)1.736044.094
Camshaft Runout (max).0012 .03
Connecting Rod Bending.0012 max per 3.94 inches .030 max per 100mm
Connecting Rod Bushing Inside Diameter.7876-.7879 20.003-20.014
Connecting Rod Cap Oil Clearance (max).004 .10
Connecting Rod Cap Oil Clearance (standard).0008-.0017 .020-.044
Connecting Rod Length, Center to Center5.231-5.234 132.85-132.95
Connecting Rod Side Clearance (max).012 .30
Connecting Rod Side Clearance (standard).0044-.0103.110-.262
Crankshaft End Play (max).012 .30
Crankshaft End Play (standard).0032-.0111.080-.282
Crankshaft Main Journal Diameter1.9661-1.9667 (max out of round, .0020) 49.938-49.956 (max out of round, .05)
Crankshaft Pin Journal Diameter1.7693-1.7669 (max out of round .0020) 44.940-44.956 (max out of round .05)
Crankshaft Runout (max).0016 .04
Cylinder Block Distortion (max).006.15
Cylinder Block Grinding (max).008.20
Cylinder Block Height8.720221.5
Cylinder Bore Concentricity (max).0007.019
Cylinder Bore Taper (max).0007.019
Cylinder Head Distortion (max).004.10
Cylinder Head Manifold Surfaces Distortion (max).006.15
Cylinder Head Manifold Surfaces Grinding (max).008.20
Cylinder Head Surface Grinding (max).004.10
Cylinder Head Height5.268-5.275133.8-134.0
HLA Bore Concentricity (standard)1.1811-1.182030.000-30.025
HLA Outside Diameter Clearance (max).0071.18
HLA Outside Diameter Clearance (standard).00099-.00259.025-.066
HLA Outside Diameter Concentricity1.1795-1.180129.959-29.975
Piston Ring End Gap (max).0391.0
Piston Ring End Gap (Oil Rail).008-.027.20-.70
Piston Ring End Gap (top/middle).006-.011.15-.30
Piston Ring Groove Clearance (max).006.15
Piston Ring Groove Clearance (middle).012-.027.03-.07
Piston Ring Groove Clearance (top).0012-.0025.03-.065
Piston to Cylinder Clearance (max).006.15
Piston to Cylinder Clearance (standard).0013-.0023.032-.059
Valve Guide Height (from head).721-.74418.3-18.9
Valve Guide Inside Diameter, Intake and Exhaust2367-.23746.01-6.03
Valve Length, Exhaust (min)3.9563100.49
Valve Length, Exhaust (standard)4.0153101.99
Valve Length, Intake (min)3.9524100.39
Valve Length, Intake (standard)4.0114101.89
Valve Margin Thickness, Exhaust (min).0391.0
Valve Margin Thickness, Intake (min).035.9
Valve Seat Contact Width.032-.055.8-1.4
Valve Spring Free Length (min)1.56 (set load of 50.2-56.7 lbf)39.5 (Set load of 22.8-25.8kgf)
Valve Spring Free Length (standard)1.82146.26
Valve Stem Diameter, Exhaust (min).23295.915
Valve Stem Diameter, Exhaust (standard).2349-.23545.965-5.980
Valve Stem Diameter, Intake (min).2331 5.920
Valve Stem Diameter, Intake (standard).2351-.23565.970-5.985
Valve Step Protruding Length (from head)1.77245.0
Valve to Guide Clearance, Exhaust (standard).0012-.0025.030-.065
Valve to Guide Clearance, Intake and Exhaust (min).008.20
Valve to Guide Clearance, Intake (standard).0010-.0023.025-.060
Wrist Pin Diameter.7869-.787119.987-19.993
Wrist Pin Hole Diameter (piston).7870-.787419.988-20.000
Wrist Pin to Connecting Rod Bushing Clearance.0004-.0010.010-.027
Wrist Pin to Piston Clearance.0002-.0005.005-.013

ARP Head Studs Kit – Part Number 218-4701 – Application: Mazda (1.6L B6 – 1.8L BP)

  1. Clean and inspect all hardware prior to installation. Look for obvious defects or shipping damages, plus proper fit, length, and dimension.
  2. To ensure proper thread engagement and accurate torque readings, clean ALL threads in the block. Chase if necessary with ARP Thread Chaser, part number: 912-0005 (M11 x 1.5).
  3. If the cylinder head studs protrude into the water jacket, lubricate the block threads of the studs with ARP THREAD SEALER.
  4. Screw studs into the block “HAND TIGHT ONLY”.
    • NOTE: Loctite may be used if a permanent mounting of the studs is preferred. The fasteners, however, must be torqued prior to the Loctite setting up.
  5. Install the cylinder head(s) and check for binding or misalignment.
  6. Lubricate the stud threads, nuts, and washers with ARP ULTRA-TORQUE FASTENER ASSEMBLY LUBRICANT.
  7. Install the washers and the nuts onto the studs and tighten them hand tight. ARP recommends using the ARP ULTRA-TORQUE FASTENER ASSEMBLY LUBRICANT that is provided with each kit as opposed to motor oil. This is due to the higher friction on the studs as well as inconsistencies in the clamping force of the fasteners when motor oil or other low-quality lubricants are used.

PRELOAD (TORQUE) RECOMMENDATIONS

  1. Following the manufacturer’s recommended torque sequence, tighten the nuts in three equal steps to 65 ft-lbs with ARP ULTRA-TORQUE FASTENER ASSEMBLY LUBRICANT.

ARP Head Stud Bolt Torque Sequence

Cambox Cover Bolt Tightening Sequence – Eleven 10mm bolts torqued to 7Nm/70kgf cm/55 INCH LBS

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Zak
Currently residing near the Black Forest in Germany, I enjoy the twisties through the Alps, Nürburgring, and back-woods roads. Current: 1999 Mazda Miata (NB) 1.8l (undergoing a full rebuild) Memorable Past: Porsche Cayenne S (955), BMW 335i (e92)

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