Valve Lash

ADJUSTMENT

Except 1.5L, 2.3L, 1997–98 1.8L (BPD) and 1998 2.0L and 2.5L Engines

The valve lash on all engines is kept in adjustment hydraulically. No adjustment is necessary, or possible.

1.5L, 2.3L, 1997–98 1.8L (BPD) and 1998 2.0L and 2.5L Engines

These engines use solid cam followers with a removable adjustment shim. The valve lash clearance is measured with the original shim installed and checked against the specification. If adjustment is necessary, the original shim is removed, and a thicker or thinner shim is installed to obtain the proper clearance. Special tools are required in order to adjust the shim without removing the camshaft.

1.5L, 1997–98 1.8L (BPD) and 1998 2.0L Engines

NOTE: With the engine cold, standard valve clearance is 0.010-0.012 in. (0.25-0.31mm) on intake and exhaust sides.

1. Remove the cylinder head cover.
2. Measure the valve clearance by turning the crankshaft clockwise until the No. 1 piston is at TDC.

   Fig. 1: Ensure that the cam lobe faces away from the follower when checking the valve clearance

3. Measure the valve clearance at A. If the clearance exceeds specifications, replace the adjustment shim.

   Fig. 2: Mazda 4-cylinder engines valve clearance checking positions

4. Turn the crankshaft clockwise 360 degrees until the No. 4 piston is at TDC. Measure the valve clearance at B. If the clearance exceeds specifications, replace the adjustment shim.
5. Repeat this procedure for all the camshafts.
6. Turn the crankshaft clockwise until the cam on the camshaft requiring the adjustment is positioned straight up.

   Fig. 3: Mazda 4-cylinder engines cam cap bolt removal positions — refer to text

7. Remove the camshaft cap bolts as follows:
8. For exhaust side No. 1, 2, and 3 cylinder adjustment shim removal use A.
9. For intake side No. 1, 2, and 3 cylinder adjustment shim removal use B.
10. For exhaust side No. 2, 3, and 4 cylinder adjustment shim removal use C.
11. For intake side No. 2, 3, and 4 cylinder adjustment shim removal use D.
12. Install special tools 49-T012-002 and 003, using the camshaft cap bolt holes. Torque the bolts to 100-125 inch lbs. (11-14 Nm).
13. Align the mark on the 49-T012-002 (shaft) with the mark on the 49-T012-003 (clamp). Tighten special tool 49-T012-004 (bolt) to secure the shaft.
14. Position special tool 49-T012-001A toward the center of the cylinder head, and mount it on the shaft where the adjustment shim needs replacement.
15. Position the notch of the tappet to allow a small pry tool to be inserted.

    Fig. 4: Mount the tappet depressor tool onto the shaft above the tappet which needs adjustment

    Fig. 5: With the tappet depressed, use a small prytool to remove the adjustment shim

16. Set the special tool on the tappet by its notch. Tighten the mounting bolt B securing it on the shaft.
17. Tighten bolt C, and press down the tappet.
18. Using a small pry tool, pry the adjustment shim upwards through the notch on the tappet. Remove the shim with a magnet.
19. Select and install the proper adjustment shim. Loosen bolt C to allow the tappet to move up, and loosen bolt B to remove special tool 49-T012-001A.
20. Remove special tools 49-T012-002, 003 and 004, and tighten the camshaft cap bolts to 100-125 inch lbs. (11-14 Nm).
21. Repeat the procedure for all necessary adjustment shims. Check the valve clearance.

2.3L and 1998 2.5L Engines

NOTE: With the engine cold, standard valve clearance is 0.011-0.012 in. (0.27-0.31mm) on intake and exhaust sides.

1. Measure the valve clearance by turning the crankshaft clockwise until the No. 1 piston is at TDC.
2. Measure the valve clearance at A. Turn the crankshaft clockwise 240 degrees until the No. 3 piston is at TDC. Measure the valve clearance at B. Turn the crankshaft clockwise 240 degrees until the No. 5 piston is at TDC. Measure the valve clearance at C.

   Fig. 6: Mazda 6-cylinder engine valve clearance checking positions

   NOTE: If the valve clearance exceeds the standard, replace the adjustment shim.

3. Turn the crankshaft clockwise until the cam, on the camshaft requiring the adjustment shim replacement, is positioned straight up.

   Fig. 7: Mazda 6-cylinder engines cam cap bolt removal positions — refer to text

4. Remove the camshaft cap bolts as follows:
   1. For right-hand (RH) exhaust side shim removal use 1.
   2. For right-hand (RH) intake side shim removal use 2.
   3. For left-hand (LH) intake side shim removal use 3.
   4. For left-hand (LH) exhaust side shim removal use 4.
5. Install special tools 49-T012-002 and 003, using the camshaft cap bolt holes.
6. Align the mark on the 49-T012-002 (shaft) with the mark on the 49-T012-003 (clamp).
7. Position special tool 49-T012-001 toward the center of the cylinder head, and mount it on the shaft where the adjustment shim needs replacement.
8. Position the notch of the tappet to allow a small pry tool to be inserted.
9. Set the special tool on the tappet by its notch. Tighten the mounting bolt B securing it on the shaft.
10. Tighten bolt C, and press down the tappet.
11. Using a small pry tool, pry the adjustment shim upwards through the notch on the tappet. Remove the shim with a magnet.
12. Select and install the proper adjustment shim. Loosen bolt C to allow the tappet to move up, and loosen bolt B to remove special tool 49-T012-001.
13. Remove special tools 49-T012-002, 003 and 004, and tighten the camshaft cap bolts to 100-125 inch lbs. (11-14 Nm).
14. Repeat the procedure for all necessary adjustment shims. Check the valve clearance.