Timing Area Oil Leaks On
                                             1990 Nissan VG30 Engines

When checking for the source of an oil leak in the timing cover area of 1990 Nissan VG30 engines used in 300ZX automobiles, be sure to check the auto tensioner for leaks.

Nissan has revised the auto tensioner, Part #13070-45V01, by relocating the oil holes and reducing the clearance between the tensioner body and piston (see illustration).  The new tensioner is available under Part #13070-45V03.

Rebuilders should verify that only the revised auto tensioner is installed on rebuilt engines.

For additional information see AERA Technical Bulletins: TB 653 & 601


                                                                          The AERA Technical Committee

                                          Interference Engines

The AERA Technical Committee would like to offer the following information on engines that present the possibility of interference between pistons and valves. The interference or contact may bend valve(s) when the timing between the camshaft and crankshaft is interrupted. This is generally the result of a timing belt or chain breaking or slipping.

The following list are engines that AERA is currently aware of that have exhibited interference. There may be other engines that are not listed below that have the possibility of piston to valve contact. If the engine you are working on is not listed, do not assume that it is a freewheeling design. It is suggested to add to this listing as additional information is obtained.

ACURA
1986-89 1.6L Integra
1991-95 1.7L Integra
1990-95 1.8L Integra 
1986-89 2.5L Legend
1992-94 2.5L Vigor
1986-89 2.7L Legend
1990      2.7L Legend
1991-95 3.0L NSX
1991-95 3.2L Legend

AUDI
1970-93 All Except 1970-77 
1.9L & 1970-73 1.8L

BMW
1987-95 2.5L 325I 525I
1994-95 4.0L 740I

CHRYSLER
1993-95 1.5L Colt 
1987-88 1.5L Colt	
1992-95 1.5L Eagle Summit
1987-88 1.6L Colt	
1989-92 1.6L Eagle Summit
1994-98 2.0L Neon Stratus
1990-95 2.0L Eagle Talon

DAIHATSU
1988-92 1.0L Charade
1988-92 1.3L Charade
1990-92 1.6L Rocky

FIAT
1974-79 1.3L 128 Series
1979-82 1.5L Stranda
1974-78 1.6L 124 Series
1974-78 1.8L 124 Series
1974-78 1.8L 131 Series, Brava
1979-82 2.0L Brava, Spider 

FORD
1981-85 1.6L Escort, EXP
1981-83 1.6L LN7, Lynx
1984-85 2.0L Escort, Tempo
1993-95 2.0L Probe
1986-88 2.0L Ranger
1984-87 2.0L Lynx, Topaz Diesel
1985    2.2L Ranger
1989-92 2.2L Probe
1986-88 2.3L Ranger
1986-87 2.3L Diesel Ranger
1991-98 4.6L Crown Victoria

GM
1986-95 1.0L Geo Metro
1989-91 1.0L Firefly (CANADA)
1985-88 1.5L Sunburst (CANADA)
1985-89 1.5L Spectrum
1990-93 1.6L Prizm, Storm
1981-84 1.8L Diesel (CANADA)
1982-86 1.8L Buick Skyhawk
1990-98 1.9L Saturn
1987-88 2.0L Buick Skyhawk
1988-95 2.3L Quad Four
1985-87 3.0L Buick
1979-95 3.8L Buick

HONDA
1986-87 1.0L Prelude
1973-78 1.2L All
1973-78 1.3L All
1980-84 1.3L All
1973-78 1.5L All
1985-89 1.5L Civic
1988-95 1.5L Civic, CRX
1993-95 1.5L Civic Del Sol
1979-84 1.5L All
1985-87 1.5L CRX
1993-95 1.6L Civic Del Sol
1973-78 1.6L All
1980-82 1.6L All
1988-95 1.6L Civic, CRX
1984-87 1.8L Prelude, Accord
1979-83 1.8L All
1986-91 2.0L Prelude
1990-91 2.1L Prelude
1990-95 2.2L Prelude, Accord
1992-95 2.2L Prelude
1995      2.7L Accord

HYUNDAI
1984-95 1.5L Excel Scoupe
1995-98 1.5L Accent
1992-95 1.6L Elantra
1993-95 1.8L Elantra
1992-95 2.0L Sonata
1989-91 2.4L Sonata
1990-95 3.0L Sonata

INFINITI
1990-92 3.0L M30

ISUZU
1987-89 1.5L I-Mark
1990-93 1.6L Stylus Impulse
1987-89 2.0L Impulse
1981-87 2.2L Diesel Truck
1986-95 2.3L Truck Trooper
1988-95 2.6L Truck Rodeo Amigo
1991-96 3.2L Trooper Rodeo Amigo

KIA
1995      2.0L Sportage

MAZDA
1984-85 2.0L 626 
1988-92 2.2L 626 MX6
1989-93 2.2L Pickup
1988-95 3.0L 929 MPV

MITSUBISHI
1985-95 1.5L Mirage Precise
1990-92 1.6L Mirage
1989-95 2.0L Galant Eclipse
1983-86 2.3L Diesel Pickup
1994-95 2.4L Galant

NISSAN
1982      1.5L Centra
1983-88 1.6L Sentra Pulsar
1987-89 1.8L Pulsar
1982-89 2.0L Stanza 300ZX
1984-95 3.0L Maxima 300ZX Pathfinder

PORSCHE
1976-83 2.0L 924
1976-89 2.5L 944 Series
1989      2.7L 944 Series
1989-91 3.0L 944 Series
1976-83 4.5L 928
1984      4.7L 928
1985-91 5.0L 928
1992-95 5.4L 928

SUZUKI
1985-94 1.3L Samurai Sidekick
1989-94 1.3L Swift

TOYOTA
1986-95 1.5L Tercel
1981-83 2.2L Pickup
1984-87 2.4L Pickup
1982-88 2.8L Celica Cressida
1987-94 3.0L 4-Runner

VOLKSWAGEN
1976-91 All Except 1.9 2.1L Engine
1990-92 1.6L Golf (CANADA) Jetta
1990-95 2.0L GTI Jetta GLI Passat

VOLVO
1991      2.3L Coupe 940
1986-94 2.3L 240 740 940 

                                                                              The AERA Technical Committee

                                     Cylinder Head Specifications On
                                     Nissan 300ZX 3.0L DOHC Engines

AERA members are advised of additional cylinder head specifications on Nissan 3.0L 300 ZX DOHC engines.  Original service manuals for this engine did not include a practical specification for measuring cylinder head thickness (dimension A).

The additional service manual information shown below is also somewhat confusing, as it requires a measurement to another imaginary line (dimension B).  

A suggested alternative method is to measure from the deck of the head to the top of the camshaft journal with the cam laying in it's bores.  That dimension on a new head should be 5.9835 (151.980 mm).  From that dimension you must subtract 1/2 of the camshaft diameter or .5505 (13.983 mm).  This method provides an actual cylinder head thickness dimension and eliminates the idea
of an imaginary line.

                                                            The AERA Technical Committee

                                 Engine Knocking Detonation Noise On
                                        1990 Nissan 3.0L VG30 Engines 

AERA members have reported engine noise on some 1990 300ZX Nissan cars.  The noise is most noticeable on acceleration, or high engine RPM under no load.  This condition is commonly called spark knock or pinging and blamed on cheap gas or gas that does not have a high octane rating.  The engine manufacturer recommends premium unleaded gasoline.

This bulletin concerns one other possible cause of engine noise. It may be from the engine PCV (Positive Crankcase Ventilation) system.  To check for this, simply collapse the rubber hose or disconnect the PCV valve.  If the noise goes away, a revised system is recommended that incorporates a smaller restriction
within the system (See illustration).

Two PCV valves (Nissan Part #11810-40P00) are used in this engine application as well as two connection hoses, Nissan Part #11823- 30P01 and 11823-30P11. 

                                                                        The AERA Technical Committee

                                         Oil Pressure Regulator Valve Caution On 
                                    1984-96 Nissan 300ZX 3.0L Non Turbo Engines

The AERA Technical Committee offers the following information regarding oil pressure regulator valve on 1984-96 Nissan 300ZX 3.0L Non-Turbo engines.

Installing a new replacement cylinder block / engine in a 300 ZX non turbo car the new block / engine assembly comes with two blind plugs installed in the oil filter bracket boos on the engine block. The original engine that is removed from the vehicle has two oil pressure regulators installed. The blind plugs must be removed and the regulator valves installed to prevent engine damage. Drill, thread and use a slide hammer to remove the blind plugs.

During the engine rebuilding process all of the cylinder block plugs / oil pressure regulators get removed, so the block can be cleaned. See Figure 1 for the correct location of the oil pressure regulator valves. At the time of printing the Nissan part number for the oil pressure regulator valve is #15241-40F00 two required. Drive in the new oil pressure regulator with a suitable tool / socket just flush with the mounting surface. 

NOTE: The 300 ZX Turbo engine has the oil pressure regulator valves installed in the oil filter bracket, and does not need this procedure. 

Figure 1.

                                                                      The AERA Technical Committee