INSPECTION

Camshaft Lobe Lift

2.3L, 2.5L, 2.6L AND 3.0L (MPV) ENGINES

Check the lift of each lobe in consecutive order and make a note of the readings. Camshaft assembly specifications are sometimes modified by Mazda after production. Refer to a local reputable machine shop as necessary.

1. Remove the valve cover.
2. Measure the distance between the major (A–A) and minor (B–B) diameters of each cam lobe with a Vernier caliper and record the readings. The difference in the readings on each cam diameter is the lobe lift.
3. If the readings do not meet specifications, replace the camshaft and all rocker arms/cam followers.
4. Install the valve cover.

3.0L (B SERIES PICK-UP) AND 4.0L ENGINES

Check the lift of each lobe in consecutive order and make a note of the reading. Camshaft assembly specifications are sometimes modify by MAZDA after production. Refer to a local reputable machine shop as necessary.

1. Remove the fresh air inlet tube and the air cleaner. Remove the heater hose and crankcase ventilation hoses. Remove valve rocker arm cover(s).
2. Remove the rocker arm stud nut or fulcrum bolts, fulcrum seat and rocker arm.
3. Make sure the push rod is in the valve tappet socket. Install a dial indicator D78P–4201–B (or equivalent) so that the actuating point of the indicator is in the push rod socket (or the indicator ball socket adapter Tool 6565–AB is on the end of the push rod) and in the same plane as the push rod movement.
4. Disconnect the I terminal and the S terminal at the starter relay. Install an auxiliary starter switch between the battery and S terminals of the starter relay. Crank the engine with the ignition switch off. Turn the crankshaft over until the tappet is on the base circle of the camshaft lobe. At this position, the push rod will be in its lowest position.
5. Zero the dial indicator. Continue to rotate the crankshaft slowly until the push rod is in the fully raised position.
6. Compare the total lift recorded on the dial indicator with the specification. To check the accuracy of the original indicator reading, continue to rotate the crankshaft until the indicator reads zero. If the lift on any lobe is below specified wear limits, the camshaft and the valve tappet operating on the worn lobe(s) must be replaced.
7. Remove the dial indicator and auxiliary starter switch.
8. Install the rocker arm, fulcrum seat and stud nut or fulcrum bolts.
9. Install the valve rocker arm covers and the air cleaner.

Camshaft End Play

2.3L/2.5L ENGINES

Remove the camshaft drive belt cover. Push the camshaft toward the rear of the engine. Install a dial indicator so that the indicator point is on the camshaft sprocket attaching screw or gear hub. Zero the dial indicator. Position a prybar between the camshaft sprocket or gear and the cylinder head. Pull the camshaft forward and release it. Compare the dial indicator reading with specifications. If the end play is excessive, replace the thrust plate at the rear of the cylinder head. Remove the dial indicator and install the camshaft drive belt cover. The camshaft end-play specification is 0.001–0.007 inch and the service limit is 0.003 inch. Camshaft specifications are sometimes modified by Mazda after production.

2.6L AND 3.0L (MPV) ENGINES

NOTE: On engines with an aluminum or nylon camshaft sprocket, prying against the sprocket, with the valve train load on the camshaft, can break or damage the sprocket. Therefore, the rocker arm adjusting nuts must be backed off, or the rocker arm and shaft assembly must be loosened sufficiently to free the camshaft.

1. Push the camshaft toward the rear of the engine. Install a dial indicator so that the indicator point is on the camshaft sprocket attaching screw.
2. Zero the dial indicator. Position a prybar between the camshaft gear and the block. Pull the camshaft forward and release it. Compare the dial indicator reading with the specifications.
3. If the end play is excessive, check the spacer for correct installation before it is removed. If the spacer is correctly installed, replace the thrust plate.
4. Remove the dial indicator.

3.0L (B SERIES PICK-UP) AND 4.0L ENGINES

1. Push the camshaft toward the rear of the engine. Install a dial indicator (Tool D78P–4201–C or equivalent so that the indicator point is on the camshaft sprocket attaching screw.
2. Zero the dial indicator. Position a prybar between the camshaft gear and the block. Pull the camshaft forward and release it. Compare the dial indicator reading with the specification. The camshaft end-play specification is 0.0008–0.004 inch and the service limit is 0.009 inch (0.007 inch on 3.0L engine). Camshaft specifications are sometimes modified by Mazda after production.
3. If the end play is excessive, check the spacer for correct installation before it is removed. If the spacer is correctly installed, replace the thrust plate.

   NOTE: The spacer ring and thrust plate are available in two thicknesses to permit adjusting the end play.

4. Remove the dial indicator.