B2300 Mazda Tribute I

Valve train is a "set-for-life" system, consisting of maintenance-free, direct-acting mechanical bucket tappets. Tappets are selective and would only require replacement with cylinder head repair or replacement. See appropriate article in ENGINES.

Scheme 25

Scheme 26

Scheme 27

Scheme 28

Scheme 29

1. Ensure engine is cold. Remove valve cover. Rotate crankshaft clockwise until No. 1 piston is at TDC of compression stroke. Measure valve clearance between base of camshaft lobe and valve tappets at "A". (Scheme 25) See «VALVE CLEARANCE SPECIFICATIONS»(ref-134956-S05677517902002022100000) table. If clearance is as specified, record valve location and clearance reading. Go to next step.
2. Rotate crankshaft clockwise about 360 degrees, positioning No. 4 piston at TDC of compression stroke. Measure valve clearance between base of camshaft lobe and valve tappets at "B". (Scheme 25) See «VALVE CLEARANCE SPECIFICATIONS»(ref-134956-S05677517902002022100000) table. If clearance is not within specification, Go to next step.
3. Turn crankshaft clockwise so that camshaft lobe on valve requiring clearance adjustment is positioned straight up, away from valve. Remove appropriate camshaft cap bolts as necessary. (Scheme 26) See «CAMSHAFT BOLT REMOVAL»(ref-134956-S12929645252002022100000) table. NOTE: For No. 2 and 3 cylinder exhaust valve adjustment shim removal, remove bolts "A" or "C". For No. 2 and 3 cylinder intake valve adjustment shim removal, remove bolts "B" or "D".
4. Assemble Adjustment Tool Shaft, Clamp and Bolt (49-T012-002, 49-T012-003 and 49-T012-004), aligning marks on adjustment tool. (Scheme 27) Install shaft and clamp on appropriate camshaft using camshaft cap bolts. (Scheme 26) Tighten cap bolts to 100-126 INCH lbs. (11.3-14.2 N.m). (Scheme 28) Tighten clamp bolt to secure shaft. (Scheme 27)
5. Mount Tappet Holder Body (49 T012 001A) on shaft toward outside of head over tappet requiring shim replacement. (Scheme 28) Position notch of tappet so that thin-blade screwdriver can be inserted. (Scheme 29) Set body on tappet and align by its notch. Tighten short bolt to secure body to shaft. CAUTION: Use caution when depressing tappet. Cylinder head can be damaged by body tip when tappet is depressed.
6. Tighten long bolt on tappet holder body to depress tappet. Using thin-blade screwdriver, pry up on adjustment shim through notch on tappet. Using a magnet, remove shim and measure shim thickness. Select proper adjustment shim to obtain clearance within specification. Push selected shim into tappet. Loosen long bolt to allow tappet to move up. Loosen short bolt and remove body. Remove shaft and clamp. Install camshaft cap bolts and tighten to 100-126 INCH lbs. (11.3-14.2 N.m). Recheck valve clearance.

VALVE CLEARANCE SPECIFICATIONS

CAMSHAFT BOLT REMOVAL

Scheme 30

Scheme 31

Scheme 32

Scheme 33

Scheme 34

1. Ensure engine is cold. Remove intake manifold and valve covers. See «REMOVAL, OVERHAUL & INSTALLATION»(ref-134974) article. Rotate crankshaft clockwise until No. 1 piston is at TDC of compression stroke. Measure valve clearance between camshaft lobe and valve tappet of both banks at "A". (Scheme 30) If clearance is not within specification, record clearance and location of valve. Go to next step. See «VALVE CLEARANCE SPECIFICATIONS»(ref-134956-S05677517902002022100000) table.
2. Rotate crankshaft clockwise about 240 degrees, positioning No. 3 piston at TDC of compression stroke. Measure valve clearance between base of camshaft lobe and valve tappet of both banks at "B". (Scheme 30) If clearance is not within specification, record clearance and location of valve. Go to next step. See «VALVE CLEARANCE SPECIFICATIONS»(ref-134956-S05677517902002022100000) table.
3. Rotate crankshaft clockwise about 240 degrees, positioning No. 5 piston at TDC of compression stroke. Measure valve clearance between base of camshaft lobe and valve tappet of both banks at "C". (Scheme 30) If clearance is not within specification, record clearance and location of valve. Go to next step. See «VALVE CLEARANCE SPECIFICATIONS»(ref-134956-S05677517902002022100000) table.
4. Turn engine clockwise until camshaft lobe of valve requiring adjustment is pointing straight up. Remove appropriate camshaft cap bolts for valves requiring adjustment. See «CAP BOLT IDENTIFICATION»(ref-134956-S31210524912002022100000) table. CAP BOLT IDENTIFICATION Cap Bolts (1) Application No. 1 Right Cylinder Head Exhaust Valves No. 2 Right Cylinder Head Intake Valves No. 3 Left Cylinder Head Exhaust Valves No. 4 Left Cylinder Head Intake Valves (1) (Scheme 31)
5. Assemble Adjustment Tool Shaft, Clamp and Bolt (49-T012-002, 49-T012-003 and 49-T012-004), aligning marks on adjustment tool. see scheme 7 Install shaft and clamp on appropriate camshaft using camshaft cap bolts. (Scheme 31) Tighten cap bolts to 99-125 INCH lbs. (11.3-14.2 N.m). Align bolts to secure shaft after alignment.
6. Rotate notch in tappet so small screwdriver can be inserted. Position Tappet Holder Body (49 T012 001A) towards center of cylinder head over tappet requiring shim replacement. (Scheme 32) Tighten tappet holder body to shaft. Tighten tappet holder bolt to compress tappet. CAUTION: Use caution when depressing tappet. Cylinder head can be damaged by body tip when tappet is depressed.
7. Using small screwdriver, pry shim from tappet. Using magnet, remove shim. (Scheme 33) If adjustment tool interferes with shim removal, install washer between adjustment tool and camshaft cap. (Scheme 34) Measure shim thickness. Change to appropriate shim thickness to meet valve clearance specification.
8. Loosen bolt compressing tappet. Remove tappet holder assembly. Reinstall camshaft cap bolts and tighten to specification. Recheck valve clearance. Install valve cover with NEW gasket. Install intake manifold. See «REMOVAL, OVERHAUL & INSTALLATION»(ref-134974) article.