13B-MSP Engine Removal and Rebuild Notes

Top-lift removal, Renesis teardown, inspection, clearances, assembly, first start and running-in notes.

1. Before removal
2. Top-lift removal
3. Preparing for dismantling
4. Disassembly order
5. Cleaning and inspection
6. Factory clearances
7. Rotor-seal packing
8. Reassembly order
9. Priming and first start
10. Running-in and oil changes

Before removal

I normally remove the engine alone through the top, leaving the Y16M-D gearbox in the car. Treat approximately 120 kg as a planning mass for the dressed engine. Check the crane’s capacity at the boom’s full working reach—not its retracted headline capacity—and use a load leveller. Put the engine stand beside or ahead of the car so the suspended engine does not have to travel across the workshop.

Before placing the engine on a stand, loosen fasteners that need the flywheel lock or very high torque, particularly the flywheel/counterweight nut and front pulley bolt. Do not loosen either without the proper holding tool.

Top-lift removal

Ordered disconnect checklist

1. Record radio/security settings if relevant, open the windows, remove the bonnet with an assistant, and disconnect the battery negative then positive terminals.
2. Remove the strut brace, engine cover, airbox, intake duct, airflow-meter connector and resonator/VFAD ducting needed for crane access.
3. Depressurise the fuel system. Drain engine oil and coolant; remove the radiator drain access panel. Recover refrigerant only if the A/C circuit genuinely must be opened.
4. Remove the radiator, electric fan/shroud assembly and upper joining hoses. Cap the transmission-cooler stubs only on an automatic car.
5. Disconnect and label H01/H02 radiator hoses, the rear heater feed/return, expansion/degas hoses and both throttle-body coolant hoses. Tie them outside the lift path.
6. Disconnect the fuel feed quick connector at the rail, cap both sides, then disconnect the purge/EVAP and brake-booster/vacuum hoses.
7. Label the four coil leads L/F, T/F, L/R, T/R and unplug the coil pack. Disconnect the engine-earth straps.
8. Disconnect the engine harness at the chosen break points. Account for the throttle body, six injectors, four coils, eccentric-shaft sensor, ECT sensor, knock sensor, OMP stepper/position switch, oil-pressure switch, alternator and starter, plus SSV, VDI, APV and VFAD/air-system solenoids on the high-power engine. Photograph clip and earth locations before releasing the loom.
9. Disconnect the secondary-air pipe/valve connections and remaining intake/vacuum brackets. Remove the upper and lower intake manifolds where clearance makes the top lift easier; cover every open port.
10. Unplug the oxygen-sensor wiring from its body-side clips. Unbolt the exhaust manifold/catalyst connection and its braces, then support the exhaust—do not let it hang from the sensor wiring.
11. Unbolt the A/C compressor and tie it securely to the body without opening its hoses. Remove or tie aside any remaining belt-driven accessory and brackets that obstruct the lift; this car has electric power steering, not an engine-driven PAS pump.
12. Disconnect the oil-cooler hoses at their engine unions, cap them immediately and retain the banjo order. Expect them to hold oil after the sump has drained.
13. Remove the starter. Support the gearbox with a broad padded jack, remove the clutch slave cylinder from the bellhousing and tie it aside without opening the hydraulic line.
14. Remove the accessible bellhousing bolts, brackets and inspection covers. Mark each bolt length and position; check twice for the upper bolts and dowel-area brackets hidden behind the engine.
15. Attach the crane to rated engine lift eyes, fit the leveller and take only the engine’s weight. Slightly loosen the engine-side mount fasteners, remove both mounts from the chassis, then remove the remaining mount brackets once the engine floats.
16. Remove the final bellhousing bolts. Adjust crane and gearbox heights until the joint opens squarely; pull the engine forward until the input shaft clears the clutch. Never draw the joint apart with wedges against the mating faces.
17. Raise a few centimetres at a time, changing leveller angle as needed. Stop after every movement and check the firewall heater hoses, oil lines, wiring behind the engine, exhaust studs, sump/crossmember and clutch/input shaft.
18. Move the free engine directly to the prepared stand. Fit correctly graded stand bolts with enough thread engagement and do not rest the engine on the sump or an oil-seal face.

Tie every disconnected hose and loom away from the lift path. The usual snags are a hidden rear earth, upper bellhousing bolt, clipped oxygen-sensor loom, oil-cooler hose, heater hose or A/C bracket. From practical experience, the first top lift took about six hours; a familiar repeat was about two hours. Those are planning observations, not labour times.

Preparing for dismantling

• Photograph every side of the dressed engine and mark front/rear orientation.
• Remove the gearbox, clutch and flywheel/counterweight while the assembly is safely restrained.
• Strip the intake, throttle body, fuel rails/injectors, exhaust manifold, coils/leads, air-system hardware, wiring loom and remaining brackets.
• Blank every oil, coolant, fuel and intake opening. Degrease the exterior before opening the housing stack.
• Set out separate trays for front and rear rotors, each divided into faces A, B and C. Label stationary gears and return every reused seal to its original groove.

Never place a rotor directly on an oil-seal face. Photograph spring, notch and side-piece orientation before moving it.

Disassembly order

This follows the revised Mazda 13B-MSP engine manual’s component order. Keep the manual’s numbered diagrams open for bolt sequences and SST placement.

External housings and lubrication parts

1. Remove the oil filter, rear and front engine hangers and ECT sensor.
2. Remove the water-pump pulley/body, thermostat cover and thermostat.
3. Remove the lower oil pan, oil-pan baffle/clip, oil-level sensor, upper pan and oil strainer. Do not lever against an aluminium sealing face.
4. Remove the OMP and keep all four pipes/nozzle positions labelled. Cap the small drillings immediately.
5. Lock the eccentric shaft with the specified tool, remove the front pulley lockbolt and pulley. The bolt is very tight; do this before insecure stand work.
6. Remove the oil-pump bypass plug carefully: its valve and spring are loaded. Remove the front cover without driving a tool into its sealing face.
7. Remove the oil-pressure-regulator plug, spring and valve; keep the order distinct from the bypass valve.
8. Mark the metering-oil-pump drive-gear orientation. Unstake/remove the oil-pump sprocket nut and lock washer, then remove the sprocket, chain, OMP drive gear, oil-pump gear and pump body/shaft components.
9. Remove the balance weight, thrust plate, thrust needle bearing and spacer. Keep the lettered end-float spacer identified.
10. If inspecting a serviceable Type A oil pump, remove its inner/outer rotors and shaft from the body. A sealed Type B pump is replaced as an assembly.

Housing stack

1. Lock the flywheel/counterweight with the SST. Remove the 54 mm locknut and flywheel/counterweight; normal thread direction applies. Do not shock-load the eccentric shaft.
2. Loosen the tension bolts in the Mazda figure order, in two or three passes, then remove them and keep the seal washers accounted for.
3. Lift the rear housing with a small rotating/wiggling motion to break the oil film. Do not drive wedges between sealing faces. A side/corner seal may remain attached: return it to its labelled position immediately.
4. Remove the rear stationary gear and rear main oil seal as specified, then the pressure regulator and rear dowel where the manual sequence requires access.
5. Lift the rear rotor housing vertically while controlling all three apex assemblies so they cannot fall. Mark housing orientation and width-measurement positions.
6. Lift the rear rotor from the eccentric shaft. Transfer every oil, cut-off, side, corner and apex seal/spring to the matching rear A/B/C tray.
7. Remove the front dowel. With an assistant supporting the eccentric shaft upward by roughly 30 mm, lift and rotate the intermediate housing just enough to clear the shaft. Do not scrape the bearing/journal or lever on the seal track.
8. Remove the front rotor housing in the same controlled way, then lift the front rotor and empty its seals into the labelled front A/B/C tray.
9. Remove the eccentric shaft and its oil-jet ball, spring and plug components without losing their order.
10. Remove the thrust components, front stationary gear/bearing and front housing. Keep both stationary gears labelled; do not interchange them.

Cleaning and inspection

Rotor housings

• Chrome flaking or chipping, chatter marks, scoring and seal-track damage
• Water-jacket corrosion and cracks around ports/dowel areas
• Width at the Mazda measuring positions and maximum width variation

Side and intermediate housings

• Flatness/distortion on a verified reference surface
• Stepped wear, inner/outer oil-seal tracks and side-seal tracks
• Port-edge damage, corrosion and cracking

Rotors and seals

• Apex- and side-seal groove clearance, damage and carbon packing
• Corner-seal bores, oil-seal grooves and rotor-bearing bore
• Heat/carbon damage and cracks, especially between grooves and combustion recesses
• Seal height, spring free height, free movement and matched position

Eccentric shaft, bearings and oil pump

• Journal diameter/finish, shaft runout and thrust surfaces
• Main- and rotor-bearing oil clearances, end play and oil passages
• Pump body, tip and side clearances; scoring or embedded debris

Iron lapping

Measure flatness and wear before deciding to lap. Use a known-flat reference plate, a suitable abrasive/carrier and controlled figure-eight strokes. Rotate the housing regularly so hand pressure cannot create taper; protect port edges rather than rolling over them. Clean and measure repeatedly, recording material removed. A uniform scratch pattern does not prove flatness. Afterward, remove every trace of abrasive from the surface, grooves and oil passages.

Factory clearances

Print this table and write measured values in the final column. A maximum is a rejection limit, not a machining target.

Measurement	Mazda standard / nominal	Service limit	My measurement
Side-housing distortion	—	0.04 mm max	__
Vertical side-housing wear	—	0.10 mm max	__
Inner oil-seal-path wear	—	0.01 mm max	__
Outer oil-seal-path wear	—	0.10 mm max	__
Stepped-path wear	—	0.02 mm max	__
Rotor-housing width difference	—	0.06 mm max	__
Rotor-to-side-housing clearance	0.05–0.19 mm	—	__
Rotor round projection	0.12–0.18 mm	0.10 mm min	__
Apex-groove clearance	0.042–0.101 mm revised	0.15 mm max	__
Apex-seal height	5.3 mm nominal	4.3 mm min	__
Long apex-spring height	5.4 mm nominal	3.5 mm min	__
Combined reused side-seal end clearance	—	0.40 mm max	__
Cut-off-seal height	3.95 mm nominal	3.80 mm min	__
Oil-seal contact width	—	0.50 mm max	__
Oil-seal projection	—	0.50 mm min	__
Rotor-bearing oil clearance	0.06–0.08 mm	0.10 mm max	__
Main-bearing clearance, without stopper	0.045–0.085 mm	0.10 mm max	__
Main-bearing clearance, with stopper	0.055–0.075 mm	0.10 mm max	__
Eccentric-shaft runout	0.02 mm	0.06 mm max	__
Eccentric-shaft end play	0.04–0.09 mm	0.10 mm max	__
Type A oil-pump body clearance	0.20–0.25 mm	0.30 mm max	__
Type A oil-pump tip clearance	0.03–0.12 mm	0.15 mm max	__
Type A oil-pump side clearance	0.03–0.125 mm	0.15 mm max	__

Older technical data gives apex-groove clearance as 0.042–0.077 mm; the revised engine manual broadens the standard range to 0.042–0.101 mm while retaining 0.15 mm maximum. Record which manual revision governs the build. New side seals are selected by groove rank rather than treated like reused seals. Letter B end-float spacer nominal thickness is 8.005 mm; its letter alone does not prove assembled end play.

Rotor-seal packing

Use the applicable Mazda orientation drawings while the parts are in hand; a simplified sketch cannot safely show every handed spring and notch.

1. Fit the inner and outer oil-seal springs in their specified directions.
2. Fit new oil-seal O-rings without twist, then install the oil seals over them. Use petroleum jelly only at the manual’s retention points and confirm free axial movement.
3. Fit the cut-off-seal springs and seals, checking direction, projection and free return.
4. Fit each side-seal spring and its matched/ranked side seal in the original A/B/C groove.
5. Fit corner springs, plugs and corner seals. Align each corner-seal notch with its apex groove and confirm the adjacent side seal moves freely.
6. Place the packed rotor on the correct front or intermediate housing with its protected face downward; engage the eccentric-shaft journal without disturbing the oil seals.
7. Fit the long and short apex springs, apex side pieces and main apex seals. The long spring must engage the side-piece stop; the side piece must not sit beneath the next housing.
8. Hold the apex assemblies inward while lowering the correctly oriented rotor housing over the rotor. Stop if force is required.
9. Recheck all exposed side/corner seals, spring return and apex movement before adding the next iron.
10. Fit new inner/outer water-jacket seals to clean grooves, untwisted and with the manual-specified lubricant, immediately before closing each housing joint.

Oil, cut-off, side and corner seals are packed on the bench before the rotor enters the stack. Apex assemblies are fitted after the rotor is on its supporting iron and before its rotor housing is lowered. Photograph each completed layer and account for every tray position.

Reassembly order

1. Place the clean front housing on its fixture. Install the labelled front stationary gear/bearing, thrust components and the selected end-float spacer in Mazda order.
2. Lubricate and fit the front rotor, its oil-jet ball/spring/plug parts and the eccentric shaft. Check that the shaft turns smoothly.
3. Fit the front rotor housing on its dowels with new water seals, controlling all apex pieces. Rotate the eccentric shaft by hand.
4. Lower the intermediate housing squarely while supporting/positioning the shaft as specified. Confirm dowel engagement and turn the shaft again.
5. Fit the packed rear rotor and rear rotor housing, followed by the rear dowel and rear housing. Check free rotation after each layer.
6. Install the rear pressure regulator, rear stationary gear and rear main oil seal in manual order.
7. Oil the tension-bolt threads and fit new seal washers. Tighten in the Mazda figure sequence over two or three passes to 31.4–39.2 Nm, checking shaft rotation between passes.
8. Measure eccentric-shaft end play; standard is 0.04–0.09 mm, maximum 0.10 mm. Change the selected spacer only from the measured result.
9. Install the thrust plate/bearing, balance weight, Type A oil pump or sealed Type B assembly, OMP drive gear, chain and sprocket. Use a new sprocket lock washer, torque 31.4–46.1 Nm and stake it.
10. Fit the bypass and pressure-regulator valves/springs/plugs to their correct bores. Fit the front cover with its seal and torque its bolts 18.6–25.5 Nm.
11. Install the pulley/seal components and torque the front lockbolt 300–340 Nm using the SST. Confirm rotation and end play again.
12. Fit the flywheel/counterweight and torque its 54 mm locknut 392–490 Nm with the specified locking method.
13. Apply the specified sealant beads to the clean upper and lower oil pans. Torque the upper pan 18.6–25.5 Nm and lower pan 8.8–11.8 Nm in sequence.
14. Refit the OMP, labelled lines/nozzles, water pump, thermostat, sensors, hangers, fuel/intake/exhaust components and ancillaries. Prime every opened oil path rather than relying on dry cranking.

See the full torque page for related fasteners.

Priming and first start

Priming

1. Fill the engine with the planned running-in oil and fit a new filter.
2. Fill the separate Sohn reservoir, prime its supply hose and OMP inlet, and verify that the line remains air-free.
3. Fill and bleed the cooling system; confirm gearbox oil if it was disturbed.
4. Inspect every fuel joint, earth, starter lead, coolant/oil hose and blanking cap.
5. Positively disable fuel and ignition—disconnecting the eccentric-shaft sensor inhibits both for Mazda’s compression procedure—and crank in short intervals with starter cooling time.
6. Confirm a credible rise on the oil-pressure gauge and inspect for leaks between cranking intervals. Re-enable fuel and ignition only after the pressure path is established.

Full-throttle clear-flood mode can inhibit injection, but positive circuit isolation is preferable for a planned first start.

First start

Once the rebuilt engine starts, allow it enough time to warm and stabilise rather than switching it off after only a few seconds, as a very short initial run can leave a fresh rotary difficult to restart.

Shut it down at once if there is no oil pressure, a major leak, uncontrolled temperature rise or abnormal mechanical noise.

Monitor oil pressure, coolant temperature, charging voltage, smoke, leaks and fan operation. Assembly oil and premix can create heavy initial smoke, but it should reduce. Fine initial material may appear in the first oil/filter; large flakes, bearing material, coolant contamination or continuing heavy debris are not normal. Open and inspect the first filter where practical.

Running-in and oil changes

This is the procedure used for this engine, not a Mazda universal schedule.

Mileage	Oil-change procedure
0–100 miles	Initial oil and filter
100–2,000 miles	Approximately every 500 miles
Beyond 2,000 miles	Approximately every 3,000–5,000 miles

Compression started relatively low and gradually increased over roughly the first 1,000 miles; no unrecorded pressures are inferred. Log raw and 250-rpm-corrected compression, oil and Sohn consumption, coolant level and filter findings at each useful checkpoint.

References

• Mazda revised 13B-MSP engine workshop manual
• Mazda RX-8 Series 1 Workshop Manual — engine removal/installation and technical-data sections.