ALL ROTARY ENGINES
See Figures 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 and 12
- 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.
- 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 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.
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
See Figure 13
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.
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.
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
See Figures 14, 15, 16, 17 and 18
- 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.
- Use a dial indicator with a sled attachment (gauge body) to check for wear on the rotor contact surfaces of the housing. Mazda offers such an attachment under part number 49-0727-570 or equivalent. To check for stepped wear on the rotor housing sliding surfaces, mount the dial indicator on the sliding surface of the housing. To measure stepped wear caused by the side seal at the sides of the housing, move the dial indicator gauge feeler to and fro as shown in the illustration. The wear limit is 0.0039 in. (0.10mm). Check the side seal stepped wear across the middle of the housing with the dial indicator, moving it as shown in the illustration. The wear limit inside the oil seal tracing marks is 0.0004 in. (0.01mm), and the wear limit outside the oil seal tracing marks is 0.0039 in. (0.10mm). Check for stepped wear by the oil seal with the dial gauge. The wear limit is 0.0008 in. (0.02mm).
- If the front, intermediate and/or rear side housings are beyond the above wear limits, they can be ground if the required finish can be maintained. If the wear is greater than the values provided above, replace the housing.
The wear at either end of the minor axis is greater than at any other point on the housing. However, this is normal and should not be cause for concern.Front Stationary Gear and Main Bearing
- Examine the teeth of the stationary gear for wear or damage.
- Be sure that the main bearing shows no signs of excessive wear, scoring, or flaking.
- Check the main bearing-to-eccentric journal clearance by measuring the journal with a vernier caliper and the bearing with a pair of inside calipers. The standard clearance is 0.0016-0.0031 in. (0.04-0.08mm). If the clearance exceeds the limit, replace the front main bearing as described later in this section.
- Unfasten the securing bolts, if used. Remove the stationary gear and main bearing assembly from the housing, using puller tool 49-0813-235 or equivalent.
- Press the main bearing out of the stationary gear.
- Press a new main bearing into the stationary gear, so that it is in the same position as the old one.
- Align the slot in the stationary gear flange with the dowel pin in the housing, then press the gear into place. On later engines, align the bearing lug with the slot in the gear. Install the securing bolts, if applicable.
Inspect the rear stationary gear and main bearing in a similar manner to the front. In addition, examine the O-ring, which is located in the stationary gear, for signs of wear or damage. Replace the O-ring, if necessary. If the stationary gear must be replaced, follow the rear main bearing replacement procedure.Rear Main Bearing Replacement
- Remove the rear stationary gear securing bolts.
- Drive the stationary gear out of the rear housing with a brass drift.
- Apply a light coating of grease to a new O-ring and fit it into the groove on the stationary gear.
- Apply sealer to the flange of the stationary gear.
- Install the stationary gear on the housing so that the slot on its flange aligns with the pin on the rear housing. On later engines, align the bearing lug with the housing slot. Use care not to damage the O-ring during installation.
- Tighten the stationary gear bolts evenly, in several stages, to 12-17 ft. lbs. (16-23 Nm).
See Figure 19
- Examine the inner margin of both housings for signs of gas or water leakage.
- Wipe the inner surface of each housing with a clean cloth to remove the carbon deposits.
- Clean all of the rust deposits out of the cooling passages of each rotor housing.
- Remove the old sealer using the proper removal solvent.
- Examine the chromium-plated inner surfaces for scoring, flaking, or other signs of damage. If any are present, the housing must be replaced.
- Check the rotor housings for distortion by placing a straightedge on the axes.
- If distortion exceeds 0.002 in. (0.05mm), replace the rotor housing.
- Check the widths of both rotor housings, at points A, B, C, and D near the trochoid surfaces of each housing, using a vernier caliper, as illustrated. Compare the difference between the value obtained at point A and the minimum value of points B, C and D. If the difference between the values obtained is greater than 0.0024 in. (0.06mm), replace the housing. A rotor housing in this condition will be prone to gas and coolant leakage.
See Figure 20
- Check the rotor for signs of blow-by around the side and corner seal areas.
- The color of the carbon deposits on the rotor should be brown, just as in a piston engine. Usually, the carbon deposits on the leading side of the rotor are brown, while those on the trailing side tend toward black (as viewed from the direction of rotation).
- Remove the carbon on the rotor with a scraper or extra fine emery paper. Use the scraper carefully when cleaning the seal grooves to avoid any damage.
- Wash the rotor in solvent and blow it dry with compressed air.
- Examine the internal gear for cracks or damaged teeth. If the internal gear is damaged, the rotor and gear must be replaced as a single assembly.
- With the oil seal removed, check the land protrusions by placing a straightedge over the lands. Measure the gap between the rotor surface and the straightedge with a feeler gauge.
Check the clearance between the housings and the rotor on both of its sides:
- Measure the rotor width with a vernier caliper at the points indicated in the corresponding illustration.
- Compare the rotor width against the width of the previously measured rotor housing.
- Replace the rotor, if the difference between the two measurements is not 0.0047-0.0074 in. (0.12-0.19mm) for the 1979-85 carbureted engine or 0.0047-0.0083 in. (0.12-0.21mm) for the 1984-90 fuel injected engine.
- If the clearance exceeds the specified values, replace the rotor. If the clearance is less than specification, it means that the internal gear must be removed. To dislodge the gear from the rotor bore, smack it lightly with a plastic-faced hammer, being careful not to damage the rotor. With the gear removed, recheck the side housing-to-rotor clearance again.
- The corner seal bores can be checked with a gauge (tool number 49 0839 15 or equivalent), available from Mazda. If neither end of the gauge can be fit into the bores, it is safe to reuse the original corner seals. If the "go" side of the gauge does fit into the bore, but the larger "no go" side does not, use new seals. If both sides of the gauge fit into the bores, the rotor must be replaced.
- Check the rotor bearing for wear, flaking, scoring or damage. Replace the bearing if these conditions are found. Check the bearing oil clearance by measuring the appropriate bearing journal diameter on the eccentric shaft with a micrometer. Next, measure the inner diameter of the rotor bearing.
The standard rotor bearing journal diameter is 2.913 in. (74mm).
- Find the oil clearance by subtracting the rotor bearing diameter from the rotor journal diameter. The standard clearance is 0.0016-0.0031 in. (0.04-0.08mm). If the clearance is greater than 0.0039 in. (0.10mm), replace the rotor bearing as described later in this section.
- Check the clearance between the rotor bearing and the rotor journal on the eccentric shaft. Measure the inner diameter of the rotor bearing and the outer diameter of the journal. The wear limit is 0.0039 in. (0.1mm); replace the bearing if it exceeds specification.
- Place the rotor on the support so that the internal gear is facing downward. Using puller tool 49-0813-240 (or equivalent) without its adaptor ring, press the bearing out of the rotor. Being careful not to damage the internal gear.
- Place the rotor on the support with the internal gear facing upward. Place the new rotor bearing on the rotor so that the bearing lug is in line with the slot of the rotor bore.
- Remove the screws which attach the adaptor ring to the special tool. Using the special tool and adaptor ring, press fit the new bearing until the bearing is flush with the rotor boss.
See Figures 21 and 22
- Examine the oil seal while it is mounted in the rotor.
- If the width of the oil seal lip is greater than 0.020 in. (0.5mm), replace the oil seal.
- If the protrusion of the oil seal is greater than 0.020 in. (0.5mm), replace the seal.
- Pry the seal out by inserting a small prybar into the slots on the rotor. Be careful not to deform the lip of the oil seal if it is to be reinstalled.
- Fit both the oil seal springs into their respective grooves, so that their ends are facing upward and their gaps are opposite each other on the rotor.
- Insert a new O-ring into each of the oil seals. Before installing the O-rings into the oil seals, fit each of the seals into its proper groove on the rotor. Check to see that all of the seals move smoothly and freely.
- Coat the oil seal groove and the oil seal with clean engine oil.
- Gently press the oil seal into the groove with your fingers. Be careful not to distort the seal. Be sure that the white mark is on the bottom side of each seal when it is installed.
- Repeat the installation procedure for the oil seals on both sides of each rotor.
See Figures 23, 24, 25 and 26
- Remove the carbon deposits from the apex seals and their springs. Do not use emery cloth on the seals, as it will damage their finish.
- Wash the seals and the springs in cleaning solution.
- Check the apex seals for cracks.
- Test the seal springs for weakness.
- Use a micrometer to check the seal height.
- With a feeler gauge, check the side clearance between the apex seal and the groove in the rotor. Insert the gauge until its tip contacts the bottom of the groove. If the gap is greater than 0.0035 in. (0.09mm) for the 1983-85 12A engine, or 0.0059 in. (0.15mm) for the 1984-90 13B engine, replace the seal. The standard range for non-turbo engines is 0.0024-0.0040 in. (0.06-0.10mm) and 0.0020-0.0040 in. (0.05-0.10mm) for turbo engines.
- Check the gap between the apex seals and the side housing by using a vernier caliper to measure the length of each apex seal. Compare this measurement to the minimum figure obtained for the rotor housing width.
- Check the apex seal spring for wear and measure its free height. If less than 0.2165 in. (5.5mm), replace the spring.
- If the seal is too long, sand the ends of the seal with emery cloth until the proper length is reached. Do not use the emery cloth on the faces of the seal.
See Figures 27 and 28
- Check the side seal free movement in the rotor groove. You should be able to press down along its length with your finger.
- Measure the side seal protrusion from the rotor surface. If the protrusion is less than 0.02 in (0.5mm), replace the side seal spring.
- Measure the clearance between the side seal and its groove in the rotor with a feeler gauge. (The standard clearance is given in the specification chart, earlier in this section.) If the clearance is greater than 0.0039 in. (0.10mm), replace the side seal.
- Using a feeler gauge, check the clearance between the side seal and the corner seal when the seals are installed on the rotor. If the clearance is greater than 0.0157 in. (0.4mm), replace the side seal. When installing a new side seal, correct the clearance between the side and corner seals by grinding the end of the side seal and the rounded corner seal with a fine file. The clearance should be 0.0020-0.0059 in. (0.05-0.15mm). If it exceeds this, the performance of the seals will deteriorate.
There are 4 different types of side seals, depending upon location. Do not mix up the seals and be sure to use the proper type of seal for replacement.Corner Seals
See Figure 29
- Inspect the corner seal and spring for wear, cracks, or damage and replace, if necessary.
- Make sure the corner seal has free movement by pressing on it with your finger.
- Measure the corner seal protrusion from the rotor surface. It should protrude at least 0.02 in (0.5mm). If not, replace the corner seal spring.
- Inspect the corner seal spring for wear.
Check the seal springs for damage or weakness. Be especially careful when checking the spring areas which contact either the rotor or the seal.Eccentric Shaft
See Figures 30 and 31
- Wash the eccentric shaft in solvent and blow the oil passages dry with compressed air.
- Check the shaft for wear, cracks, or other signs of damage. Make sure that none of the oil passages are clogged.
- Measure the shaft journals. Replace the shaft if any of its journals show excessive wear.
- Check eccentric shaft run-out. Rotate the shaft slowly and note the dial indicator reading. Run-out should not exceed 0.0047 in. (0.12mm) as measured from the end of the shaft. If run-out is greater than specification, replace the eccentric shaft.
- Check the blind plug at the end of the shaft. If it is loose or leaking, remove it with an Allen wrench and replace the O-ring.
- Check the operation of the needle roller bearing for smoothness by inserting a mainshaft into the bearing and rotating it. Examine the bearing for signs of wear or damage. Check the oil jet for spring weakness, sticking or ball damage.
- Replace the bearings, if necessary, with special bearing replacer tools 49-0823-073 and 49-0823-072, or equivalent.
- Inspect the needle bearing for wear and damage.
- Inspect the bearing housing and the thrust plate for wear and damage.
- Lay the chain on a flat surface and check the entire length for broken links.
- Check the oil pump drive and driven sprockets for missing and broken teeth.
- Replace parts as necessary.