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TIMING CHAIN INSTALLATION ON 79-85 MAZDA 2.0L |
Timing Chain Installation On
1979-85 Mazda 2.0L Engines
Correct installation of the timing chain on 1979-85 Mazda 2.0L
engines is critical to achieve the proper valve timing.
Rather than aligning the camshaft and crankshaft gears with marks
on the cylinder head or block, this engine uses marked plates on
the timing chain to set valve timing.
Start the timing process by rotating the crankshaft and camshaft
sprockets until the keyways are facing straight up (12 o'clock).
This should face the camshaft sprocket timing mark at 3 o'clock
and the crankshaft sprocket timing mark at approximately 5
o'clock looking at the front of the engine.
Locate the three marked links on the timing chain. Two links
should be positioned at the crankshaft sprocket so that the
timing mark is between the links (Figure 1). Position the chain
and camshaft sprocket so that the mark is in the middle of the
other marked link (Figure 2). There should be 20 unmarked plates
between the two positions.
Be careful, some timing chains do not use marked plates to
indicate the correct timing positions for the camshaft and
crankshaft. Use the old chain as a guide to make your own marks
on the new chain.
The AERA Technical Committee
August 1991 - TB 796
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VALVE TRAIN NOISE ON MAZDA 2.0L ENGINES |
Valve Train Noise On
1993-94 Mazda 2.0L Engines
The AERA Technical Committee offers the following information regarding a valve train noise on 1993-94 Mazda 2.0L engines. This noise can be associated with the Hydraulic Lash Adjusters (HLA).
This noise appears after the engine has been run at idle for a long period of time. The noise appears because air is entering the oil gallery. To prevent this condition from happening, Mazda had redesigned the oil pump plunger as shown in Figure 1.
HLA noise will appear at the top of the engine and is several times faster than that of the engine speed. Verify the complaint by running the engine at idle for a period of time not letting the vehicle overheat. If the HLA noise is present, replacement of the oil pump plunger is required.
To replace the oil pump plunger, remove the snap ring at the bottom of the pump as shown in Figure 1. Remove spring seat, pressure spring and the plunger. Replace the old plunger with the new plunger, Part #JF01 14 115. Reassemble the bottom of the oil pump in the reverse procedure of disassembly
NOTE: Follow instructions in the service manual for disassembly and assembly of the engine to get access to the oil pump for replacement of the plunger.
The AERA Technical Committee |
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COOLANT IN THE OIL |
Coolant In The Oil On
Mazda 1.5 & 1.6L Engines
AERA member machine shops should carefully inspect the cylinder head when resolving engine oil contamination complaints.
The cylinder head carries two cup type freeze plugs on the valve spring side of the cylinder head. Leaking freeze plugs will accumulate a black residue during operations. Pressure testing the cylinder head confirms that the plug or plugs were leaking.
Successful repairs include replacement of the plug or peening the metal surrounding the plug over it. Be sure to re-pressure test the cylinder head after repairs are completed.
The AERA Technical Committee |
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OIL CONSUMPTION ON 1989-94 3.0L VIN JE |
Oil Consumption On
1989-94 Mazda 3.0L VIN JE Engines
The AERA Technical Committee offers the following information on oil consumption on 1989-94 Mazda 3.0L VIN JE engines. The area of concern causing this oil consumption is the cylinder head. At this time, only the single
overhead cam (SOHC) heads have been affected. It appears this cylinder head is prone to cracking on the valve spring side of the head as mentioned in AERA Technical Bulletin TB-1260.
In at least some of the instances reported a dissimilar crack as described in TB 1260 has been observed. These cracks have allowed oil to enter the combustion process around either valve guide. These cracks create a passage
for hot engine oil to seep through the openings or voids created. Engine oil collects in this area of the head, allowing ample amounts of oil to pass. There have been reports of one quart of oil consumed in 50 miles driven.
The extent of these cracks in most instances has been too excessive to warrant successful welding repairs as some have been reported to be longer than 6 inches. In other instances where the cracks have not been so severe but
leakage was detected, welding has provided a successful repair.
The AERA Technical Committee |
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ENGINE OVER COOLING |
Engine Over Cooling
On 1994-97 Mazda 2.3L VIN A Engines
The AERA Technical Committee offers the following information on engine over cooling on 1994-97 Mazda 2.3L VIN A engines. Some customers have complained there is insufficient heat coming from the heater in the cab of the vehicle.
One cause of this type of condition may be a casting slag from the cylinder head that has become lodged in the thermostat housing. When this occurs, the
thermostat is unable to close completely. That opening allows the engine to over cool or never warm up to the correct operating temperature. To repair this problem, flush the entire cooling system (engine and radiator) to remove any slag that could be left in the engine.
To cure this problem at the factory, Mazda revised the cylinder head casting process during the 1997 model year.
The AERA Technical Committee |
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VALVE SPRING IDENTIFICATION |
Valve Spring Identification On
Mazda 1.6L DOHC Engines
Mazda uses a different valve spring for the intake and the exhaust valves on their 1.6L DOHC engines. The difference is often not noted until after the cylinder head components have been cleaned. This engine uses a rectangular spring design for intake and a common round design for exhaust valves.
The valve spring specifications are also different for each of the springs. Refer to the chart below to identify and test the valve springs for reuse.
Description Intake (Rectangular) Exhaust (Round)
Valve Spring 1.890 1.902
Free Length
Test Pressure 49-55 lbs. 40-44 lbs.
@ 1.555 @ 1.555
Installed Spring 1.555 1.555
Height
Both springs use the same retainer and keepers. Remember to replace worn or defective keepers in pairs.
The AERA Technical Committee |
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MAIN BEARING INSTALLATION CAUTION |
Main Bearing Installation Caution On
1983-91 2.0 & 2.2L Mazda Engines
AERA members report occasional difficulties when installing main bearings on Mazda 2.0 & 2.2L engines used in automotive and industrial applications. The problem arises when a technician attempts to install the lower bearing shell into the main bearing cap.
Normally the bearing will snap into place, so that the bearing tang is fully seated into the cap's receiver groove. However it appears that some main bearing caps were inadvertently manufactured with an insufficient groove length. This will not allow the bearing tang to fully seat into the cap and may cause the crankshaft to lock up when the main bearing caps are torqued to specification.
In this situation, you may be tempted to simply replace the main bearing set. Unfortunately, the problem lies with the main bearing cap, not the main bearing itself. Further, there has been no consistency with this problem, which makes it very difficult to anticipate. The bearing tang length of both OE and aftermarket bearings measure .137-.138 (3.480-3.505mm). The bearing tang requires .005-.008(.127-.203mm) end clearance for proper installation.
If this problem occurs, consider these two solutions: increase the length of the receiver groove in the cap, or decrease the length of the bearing tang.
The preferred method is to remove metal from the main bearing cap. This may be accomplished by the use of a hand grinder and a small stone or disc. Some shops have also made effective repairs with a small hand file.
The AERA Technical Committee |
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STARTUP VALVE TRAIN NOISE |
Valve Train Noise At Startup On
1989-92 Mazda 3.0L SOHC Engines
AERA members have reported valve train noise at startup on 1989-92 Mazda 3.0L SOHC engines. This noise may last longer than one minute depending upon conditions at the time of start up. This noise may be due to air that can become trapped in the engine's hydraulic lash adjuster (HLA).
When an engine is shut off, oil may be forced out of the HLA by valve spring pressure. Generally those valves that remain open while the engine is not running will then make the most noise when the engine is restarted.
To prevent air from being trapped in the HLA, a revised rocker shaft with improved oiling is available. There are two separate shafts, one for exhaust valves, Part #JF0112160B and one for intake valves, Part #JP0112170C. Every engine requires a quanity of two rocker shafts of each part numbers.
The AERA Technical Committee |
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OIL CONTROL PLUG INSTALLATION |
Oil Control Plug Installation On
Mazda 2.5 & 3.0L Engines
The Mazda 2.5 & 3.0L engine uses one oil control plug in each cylinder bank to meter the amount of oil that reaches the cylinder heads.
These plugs should be installed to a height of .209-.224 (5.30-5.70mm). Coat the new O-ring with engine oil and install one on each oil control plug. Then position each cylinder head gasket on the appropriate cylinder bank with
the identification marks facing up. The head gasket for the left bank is marked L, while the right bank is marked R. The right and left bank on this engine is determined when viewing the engine from the flywheel end.
Failure to re-install the oil control plug may result in excessive oil consumption complaints.
The AERA Technical Committee |
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REVISED CYL HEAD GASKET ON 92-94 ENGINES |
Revised Cylinder Head Gasket On
1992-94 Mazda 2.6L Engines
The AERA Technical Committee has been informed of a revised cylinderhead gasket for 1992-94 Mazda 2.6L engines. This revised gasketfeatures improved sealing at the engine's right side, rear corner(see illustrations below). The previous design head gasket mayallow coolant to leak externally at this location.
The revised head gasket Part #G601 10 271C is interchangeable withthe previous gasket. Mazda recommends that only this new gasket beused when servicing the engine.
The AERA Technical Committee |
