ROTARY ENGINE OVERHAUL

Disassembly of External Components

Because of the design of the rotary engine, it is not practical to attempt component removal and installation. It is best to disassemble and assemble the entire engine, or go as far with the disassembly and assembly procedure as needed.

CARBURETED ENGINE

Remove the engine from the vehicle and mount on a suitable stand or holding fixture.

To simplify reassembly, mark or label all components before disassembly.

Remove the oil hose support bracket from the front housing.

Disconnect the vacuum hoses and air hoses, then remove the decel valve.

Remove the air pump and drive belt. Remove the air pump adjusting bar.

Remove the alternator and drive belt.

Disconnect the metering oil pump connecting rod, oil tubes and vacuum sensing tube from the carburetor.

Remove the exhaust manifold cover, if equipped. Remove the carburetor and intake manifold as an assembly.

Remove the gasket and two rubber O-rings.

Remove the thermal reactor/exhaust manifold and gaskets. Remove the engine mount.

Remove the distributor.

On 1984-85 models, disconnect and remove the oil cooler assembly, as described earlier in this section. Do not remove the oil filter from the cooler housing unless replacement is desired.

Unbolt the A/C compressor pulley and remove the water pump.

FUEL INJECTED ENGINE

Non-Turbo

Remove the engine from the vehicle and mount on a suitable stand or holding fixture.

To simplify reassembly, mark or label all components before disassembly.

Remove the air conditioning compressor and the power steering pump bracket.

Remove the left engine mount, spark plugs, oil level dipstick, oil filler pipe, oil filter and filter body.

Remove the oil pressure gauge and distributor/crank angle sensor.

Remove the air pump, drive belt, and air pump bracket.

Remove the alternator and drive belt.

If so equipped, remove the clutch cover and clutch disc.

Remove the metering oil connecting rod, second vacuum piping, and throttle/dynamic chamber.

Remove the primary fuel injector and distribution pipe.

Remove the air control valve, switching actuator, water pipe and air hose.

Remove the housing oil nozzle and manifold oil nozzle, intake manifold, exhaust manifold and insulator.

Remove the metering oil pump, eccentric shaft pulley, and water pump.

Remove the dynamic chamber bracket, engine harness and vacuum piping, and finally, the oil inlet pipe.

Turbo

Remove the engine from the vehicle and mount on a suitable stand or holding fixture.

To simplify reassembly, mark or label all components before disassembly.

Remove the air conditioning compressor and the power steering pump bracket.

Remove the left engine mount, spark plugs, oil level dipstick, oil filler pipe, oil filter and filter body.

Remove the oil pressure gauge and crank angle sensor.

Remove the air pump, drive belt, and air pump bracket. Remove the alternator and drive belt.

If so equipped, remove the clutch cover and clutch disc.

Remove the metering oil pump connecting rod, secondary vacuum piping, and throttle/dynamic chamber.

Remove the primary fuel injector and distribution pipe. Remove the air control valve, switching actuator, water pipe, turbocharger with insulator, and the air hose. Cover the intake and exhaust port openings of the turbocharger with masking tape to prevent the entry of dirt and foreign matter.

Remove the housing oil nozzle and manifold oil nozzle, intake manifold, exhaust manifold and insulator.

Remove the metering oil pump, eccentric shaft pulley, water pump, dynamic chamber bracket, engine harness and vacuum piping, and finally, the oil inlet pipe.

Disassembly of Internal Components

ALL ROTARY ENGINES

Invert the engine.

Remove the oil pan retaining bolts. Remove the oil pan and the oil strainer. It may be necessary to drive a scraper with a blade at least 1.2 in. (30mm) wide and 0.06-0.08 in. (1.5-2.0mm) thick between the pan and the rear housing to free the pan. Be very careful not to damage the housing or the pan while removing.

Remove the oil strainer and gasket.

 

 

 

It will be necessary to lock the flywheel/flexplate to remove the pulley from the front of the eccentric shaft. For manual transmissions, Mazda offers a brake device (tool number 49-1881-060 or equivalent for earlier models, and tool number 49-FO11-101 or equivalent for later models). For automatic transmissions, Mazda offers a stopper which fits on the counterweight (tool number 49-1881-055 or equivalent). With the flywheel/flexplate locked, remove the bolt from the eccentric shaft pulley and remove the pulley.

Identify the front and rear rotor housings with a felt tip pen. These are look-alike parts and must be identified to be assembled in their respective locations.

Turn the engine on the stand so that the top of the engine is up.

Remove the engine mounting bracket from the front cover.

Remove the eccentric shaft pulley. On 1986-89 models, remove the eccentric shaft bypass valve and spring. On 1985-89 models, remove the O-ring from the eccentric shaft lockbolt and discard it. Remove the eccentric shaft pulley boss (1986-89). Turn the engine on a stand so that the front end of the engine is up.

On 1986-89 models, unscrew and withdraw the oil pressure control valve and actuating spring from the bore in the front cover. Unbolt and remove the front cover with the gasket. Slide the distributor drive gear from the eccentric shaft. The gear is retained with a key. Remove the key from the keyway and tape it to the gear.

Remove the O-ring from the oil passage on the front housing.

Remove the oil slinger and distributor drive gear from the shaft.

Unbolt and remove the chain adjuster.

Rotor, apex and side seals are identified by a number which corresponds to the number on each rotor face seal groove

If a seal sticks to the housing during removal, put it back on the rotor

Removing the rotor from the intermediate housing

Remove the locknut and washer from the oil pump driven sprocket.

Slide the oil pump drive sprocket and driven sprocket, together with the drive chain, off the eccentric shaft and oil pump, simultaneously.

Detach the baffle plate from the oil pump (turbocharged engines only). Remove the keys from the eccentric and oil pump shafts. Remove the oil pump.

Slide the balance weight, thrust washer and needle bearing from the shaft.

Unbolt the bearing housing, then slide the bearing housing, needle bearing, spacer and thrust plate off the shaft.

Turn the engine on the stand so that the top of the engine is up.

If equipped with a manual transmission, remove the clutch pressure plate and clutch disc. Remove the flywheel with a puller. Remove the key from the shaft.

If equipped with an automatic transmission, remove the drive plate. Remove the counterweight. Block the weight and remove the mounting nut. Remove the counterweight with a suitable puller. On 1986-89 engines, remove the counterweight stopper.

Working at the rear of the engine, loosen the tension bolts evenly in small stages to prevent distortion. Mark the tension bolts to replace in their original holes during reassembly.

When removing the tension bolts, refer to the appropriate removal illustration. 1984-85 carbureted engines do not have a No. 6 tension bolt, so delete that bolt from the illustration if it is not applicable.

Lift the rear housing off the shaft.

Remove the intermediate housing while applying upward pressure to the eccentric shaft

Use a special tool to remove the rotor outer oil seal

Remove any seals that are stuck to the rotor sliding surface of the rear housing and reinstall them in their original locations.

Remove all the corner seals, corner seal spring, side seal and side seal springs from the rear side of the rotor. Mazda has a special tray which holds all the seals and keeps them separated to prevent mistakes during reassembly. Each seal groove is marked with numbers near the grooves on the rotor face to prevent confusion.

Remove the two rubber seals, two O-rings or oil seal from the rear rotor housing. Remove the pressure regulator and the rear rotor housing side pieces.

Remove the tubular dowels from the rear rotor housing using puller tool 49-0813-215A or equivalent.

Lift the rear rotor housing away from the rear rotor, being very careful not to drop the apex seals on the rear rotor. Remove the O-ring from the upper dowel hole.

Remove each apex seal, side piece and spring from the rear rotor and separate them accordingly.

Remove the rear rotor from the eccentric shaft and place it upside down on a clean rag. Do not place the rotor on a hard surface.

Remove each seal and spring from the other side of the rotor and separate them.

If some of the seals fall off the rotor, reinstall being careful not to change the original position of each seal.

Identify the bottom of each apex seal with a felt tip pen.

Remove the oil seals and the spring. The outer oil seal is removed with the use of special tool 49-0813-225 or equivalent. Do not exert heavy pressure at only one place on the seal, since it could be deformed. Replace the O-rings in the oil seal when the engine is overhauled.

Hold the intermediate housing down and remove the dowels from it using an appropriate pulling tool.

Lift off the intermediate housing, being careful not to damage the eccentric shaft. Slide the intermediate housing beyond the rear rotor journal on the eccentric shaft, while pushing the eccentric shaft up. Lift out the eccentric shaft.

Repeat to remove the front rotor housing and front rotor.

CLEANING

Front, Rear and Intermediate Housings

Remove carbon from the housings with extra fine emery paper. If you use a carbon scraper, be very careful not to damage the finished surfaces of the housing. Remove the sealant remnants with a cloth or brush soaked in a solution of ketone or thinner.

Rotor Housing

Remove carbon from the inner surface of the rotor housing by wiping it off with a cloth. Soak the cloth in a solution of ketone or thinner, if the carbon is difficult to remove. Rust deposits should be carefully removed from the cooling water passages on the housing. Remove sealant remnants with a cloth or brush soaked in ketone or thinner. Be careful not to remove the felt tip pen marks made while disassembling the engine.

Rotor

Remove carbon with a carbon remover or extra fine emery paper. Clean the rotor in a standard cleaning solution and blow dry with compressed air.

Clean the rotor housing using a clean cloth which has been soaked in solvent

Seals and Springs

Gas seals can be cleaned in a standard cleaning solution. Never attempt to clean seals with emery paper or you will ruin them. Be careful not to damage the seals or springs while handling them. Do not mix up the seals and springs when cleaning.

Eccentric Shaft

Immerse the shaft in cleaning solution and blow the oil passages dry with compressed air. Apply a light film of clean engine oil to the shaft to prevent rusting.

INSPECTION AND COMPONENT REPLACEMENT

Front, Intermediate and Rear Housings

Check the housing for signs of gas or water leakage.

Remove the sealing compound from the housing surface with a cloth or brush soaked in solvent or thinner.

Remove the carbon deposits from the front housing with extra fine emery cloth. When using a carbon scraper, take extra care not to damage the surface of the housing.

Check for distortion by placing a straightedge on the surface of the housing. Measure the clearance between the straightedge and the housing with a feeler gauge. If the clearance is greater than 0.0016 in. (0.04mm) at any point, replace the housing.

Engine rebuilding is also covered under our video section

Check the rotor housings for warpage along these lines

Checking for housing wear with a dial indicator and gauge body