| PISTON & ROD ASSEMBLY & ROD BOLT REUSE |
Piston & Rod Assembly & Rod Bolt Reuse for
1989-99 Toyota 1.6 & 1.8L 4A-FE & 7A-FE Engines
The AERA Technical Committee offers the following information on piston and rod assembly and rod bolt reuse for 1989-99 Toyota 1.6 & 1.8L 4A-FE & 7A-FE engines. This information should be used to correctly assemble the pistons to connecting rods and determine whether a connecting rod bolt should be considered for reuse.
Rod bolts considered for reuse should be free of nicks and burrs and allow easily threading the bolt or nut with one's fingers. To further consider the rod bolts for a 1.6L engine, measure the bolt diameter with a caliper at .590 (14.986 mm) from the bottom of the bolt. If the diameter measured at that location is .3386 (8.6000 mm) or greater the bolt may be reused.
To further consider the rod bolts for a 1.8L engine, measure the bolt diameter with a caliper at .787 (20.000 mm) down from the bottom of the connecting rod bolt head. If the diameter measured at that location is .270 (7.000 mm) or greater the bolt may be reused
To assemble the connecting rods for either engine to the pistons, align the protrusion or front mark on the rod with the front mark located on the piston as shown in the illustrations below.
The AERA Technical Committee |
| COOLANT IN THE ENGINE OIL SUPPLY |
Coolant In The Oil On
Toyota 20R & 22R Engines
AERA members have reported instances of engine coolant mixing with the engine lubricating oil supply.
In some of these cases, pressure testing the cylinder block and head has not identified the source of the leak. However, close inspection of the aluminum front cover revealed an area where the timing chain wore through into a water passage.
In this engine the water pump is mounted to the front cover. When the timing chain stretches and the automatic tensioner is no longer able to take up the slack, the loose chain can slap against the front cover. Continuous contact will eventually wear a hole into the front cover, introducing engine coolant into the
crankcase.
The AERA Technical Committee |
| VALVE SEAL IDENTIFICATION FOR TOYOTA 1.8L ENGINES |
Valve Seal Identification For
2000-2002 Toyota 1.8L Engines
The AERA Technical Committee offers the following information on valve seal identification for 2000-2002 Toyota 1.8L engines. Starting with the 2000-year model Toyota offered two 1.8L engines with similar displacement, a 1ZZ-FE and a 2ZZ-GE designation.
Determining which engine you're working on may be confusing, as many components are similar. Valve stem seals fall into the confusing category, as they physically appear the same at first glance. Original equipment and some aftermarket seals are color coded to ease in seal identification. Refer to the chart and Figure 1 below to help identify the seals once they?re out of their original packaging.
Engine Model Location Coloring Part Number Stem Diameter
1ZZ-FE Exhaust Gray 9008031046 .2152-.2157
1ZZ-FE Intake Light Brown 9091302101 .2154-.2159
2ZZ-GE Exhaust Green 9091302115 .2144-.2154
2ZZ-GE Intake Black 9091302114 .2150-.2156
Valve guides are also slightly different between the two engines, which offers additional means of engine identification. The installed guide height and the guide outside diameter are different as the 2ZZ-GE engine protrudes higher than the 1ZZ-FE. The 2ZZ-GE guides should be .602-.618 above the spring seat while the 1ZZ-FE guides should be .342-.358 above the spring seat.
The AERA Technical Committee |
| REVISED TIMING BELT & TENSIONER SPRING |
Revised Timing Belt &Tensioner Spring For
1992-96 Toyota 2.2L 5S-FE Engines
The AERA Technical Committee offers the following information on a revised timing belt tensioner spring for 1992-96 Toyota 2.2L 5S-FE engines. This information should be considered anytime the timing belt is removed from the engine.
The timing belt and tensioner spring for 5S-FE engines has been revised beginning with the 1997-year model. The timing belt and spring are designed for use, as a set and one should not be replaced without replacing the other. All 1992-96 engines should be updated with the revised spring and belt as a set for improved durability. Intermixing prior and revised components should not be attempted as improper tension and alignment may occur.
Prior Part Number Current Part Number Description
90507-18030 90507-17003 Tension Spring
13568-09040 3568-09041 Timing Belt
Its 4mm shorter length and additional 3 coils can identify the revised spring.
The AERA Technical Committee |
| REVISED PCV VALVE ON 2.2L 4YEC ENGINE |
Revised PCV Valve On
1984-87 Toyota 2.2L 4YEC Engines
The AERA Technical Committee offers the following information
concerning a revised PCV (Positive Crankcase Ventilation) valve on
1984-87 Toyota 2.2L 4YEC engines. The purpose of this revised
assembly is to improve the control of the PCV system in colder
ambient temperatures.
This revised system involves installing a new valve and hose
assembly as shown below. Installing the revised components seals and
meters the air flow through the system in all ambient temperatures.
If the PCV system is not completely sealed, it becomes ineffective
and may result in undesirable oil consumption.
Engines built beginning with serial number 4Y-0058330 have the
revised components. Parts are available with Part #12204-15022 for
the valve and 12261-73021 for the hose assembly to update older
engines.
The AERA Technical Committee
October 1996 - TB 1387
##END## |
| OIL CONSUMPTION ON 3S-GE AND FE ENGINES |
Oil Consumption On
1986-88 Toyota 2.0L 3S-GE & FE Engines
The AERA Technical Committee offers the following information about oil consumption on 1986-88 Toyota 2.0L 3S-GE & FE engines. The cause of this condition has been related to inadequate piston ring seal. During the 1988 model year, Toyota modified the piston rings for the above mentioned engines. Generally, a field fix of installing the newer ring design solved excessive oil consumption complaints.
The modification to the ring set included reduced allowable oil ring end gap and additional tension for the 3S-FE engine. Refer to the chart below when fitting piston rings to bores.
Engine Ring & Location Previous Seec Current Spec.
3S-FE Oil ring end gap .0078-.0276 .0078-.0177
3S-GE Oil ring end gap .0078-.0276 .0078-.0177
Oil ring tension 4 kg 4.5 kg
3S-GE Second comp. .0090-.0138 .0177-.0236
ring end gap
The improved standard ring sets from Toyota carry part number 13011- 88363 for the 3S-GE engine and 13011-74071 for the 3S-FE engine.
The AERA Technical Committee |
| REVISED CRANKSHAFT CAUTION |
Revised Crankshaft Caution On
1994 Toyota 2.2L 5SFE Engines
The AERA Technical Committee advises members of a revised crankshaft design on 1994 Toyota 2.2L 5SFE engines. This design change prevents the interchanging of old and new designs. The modified area is the drive gear for the engine balance assembly.
To reduce cold engine noise at start-up, the number of teeth on the balance shaft drive gear was reduced from 66 to 44. The change occurred with engine serial #55537901, which was built in July of 1994.
The balance shaft assembly gears also changed at the same time to accommodate the revised crankshaft. The first design used 32 teeth on each gear and the second uses 22 teeth. Those assemblies are not interchangeable.
For additional information see AERA Technical Bulletin TB 1347
The AERA Technical Committee |
| ENGINE OVERHEATING |
Engine Overheating On
1988-95 Toyota 3.0L 3VZE Engines
The AERA Technical Committee offers the following information on reported engine overheating on 1988-95 Toyota 3.0L 3VZE engines. This overheating has been reported shortly after cylinder head gasket replacement. The cause of this problem has been related to incorrect location of this V-6 engine's cylinder head gaskets.
The head gaskets used on this engine are unique to each cylinder bank. It is, however, possible to install either gasket on the opposite bank of which it is indented to fit. If this is done, the engine's cooling flow will be interrupted. If that occurs, eventual engine overheating will result. The gaskets will not physically match up, if installed end for end.
To distinguish the different gaskets, original equipment and some aftermarket gasket companies provide identification by a raised color marking on the head gasket face. The left bank head gasket is color coded with a yellow dot and the right bank side is identified with a pink dot. Still other manufacturers' gaskets may have the letter L for left bank, or R for the right bank as viewed from
the flywheel end of the engine. Finally, some manufacturers do not distinguish their gaskets and supply only an instruction sheet for the correct installation.
Correct gasket installation shown below, requires that the open cooling hole is located on the left bank as viewed from the flywheel end of the engine. The right bank water passage is blocked off by the head gasket. It should also be noted that along with the head gasket differences, the heads are also location specific.
The AERA Technical Committee |
| REVISED OIL PUMP & CAMSHAFT FOR 5M-GE ENGINES |
Oil Pump And Camshaft Changes On
1984-85 Toyota 5M-GE Engines
Toyota has announced modifications for its 5M-GE engines built in 1984 and 1985 to improve the lubrication performance of the engine's camshafts. This dual overhead camshaft 6-cylinder engine has suffered a lack of adequate oil to the camshafts in the past.
Toyota engineers have increased the capacity of the oil pump to increase the oil supply to the top end. This change also necessitated a change in the shape of the oil pan to provide adequate clearance for the new oil pump. This change began with engine #5M-3581713 in August, 1984. If the original oil pump
#15100-43010 is replaced with the new oil pump #15100-43020, oil pan #12101-43040 must also be used.
The diameter of the oil jet in the camshaft was increased from .048 to .056. This change occurred in production beginning in May, 1985, with engine #5M-3675931 (see Figure 1). Toyota allows the replacement of camshafts in engines built prior to May, 1985 with the new camshaft without changing the oil pump and oil pan. The oil pressure switch should also be changed to the late model
switch. The original camshaft #13501-43010 has been replaced by #13502-43030. The correct oil pressure switch for use with the late model camshaft is #83530-14050.
The AERA Technical Committee |
| O/S CON. ROD & MAIN H/B ON 1AC,3AC,22R AND 5M-GE |
Oversize Connecting Rod And Main Bearing Housing Bores On
Toyota 1AC, 3AC, 22R And 5M-GE Engines
Toyota engineers have followed Honda's footsteps in attempting to maintain closer bearing clearances in the above engines by using different bearings with oversize ODs. If connecting rod and main saddle housing bores are not reconditioned, it will be necessary to use Toyota's elaborate system to determine proper bearing selection. This will insure adequate bearing crush and proper oil clearances. Insufficient bearing crush due to an oversize
housing may result in catastrophic failure if standard OD bearings are used in oversize housings.
On 1AC, 3AC, and 22R engines Toyota has stamped the correct code number on the side of each connecting rod and on the oil pan rail near the rear of the block. This same code appears on toyota's bearing part number as the last two digits. These codes are -01, -02, -03, -04 and -05. Numbers stamped on the connecting rods and blocks drop the -0 and use just the single digit. 1985 and later 22R engines use the letters A, B, C, D and E.
Toyota has taken this system one step further with its 5M-GE engines built after June, 1984. A three number system is used for the crankshaft (0, 1 or 2) and the housing bores of the connecting rods and main saddles (1, 2 or 3). Figure 1
illustrates the location of the crankshaft stampings. The connecting rods are stamped on their sides and the oil pan rail is stamped for the main saddles. See Figure 2.
The correct bearing suffix number is obtained by adding the number stamped on the crankshaft to the number stamped on the connecting rod or block. You should end up with a number of 1, 2, 3, 4 or 5. The larger the size number, the more undersized the bearing. For example, if the crankshaft was stamped with a
0 and the connecting rod was stamped with a 2, the proper suffix for your replacement rod bearing would be 0 + 2 = 2.
It is impossible to accidentally mix new style bearings with old style bearings in the 5M-GE engine. The indexing tab location was reversed on the connecting rods and the number one main bearing when the new style was introduced in June, 1984.
Proper oil clearance for 5M-GE engine connecting rods is .0008-.0021 (.021-.053mm) and .0013-.0023 (.034-.058mm) for the mains. Proper oil clearance for 1AC, 3AC and 22R engine main bearings is .0005-.0019 and .0008-.0020 for the connecting rods. If the oil clearance is not within specifications, a different size bearing must be selected or the crankshaft must be reground.
The AERA Technical Committee |
