Abnormal Cylinder Wall Wear

Cylinder wall wear falls into two categories.  The first type is wear that occurs over the life of the engine.  The second kind is rapid wear that limits the engine's life to just a few thousand miles or less.

Premature engine failure due to excessive and rapid cylinder wall wear in the ring travel area is usually due to dirt contamination of the intake charge or the lubricating oil supply (see illustration).  

If the excessive wear is located at the top of the cylinder bore only, it was caused by dirt particles entering the engine through the intake system.  A defective air filtration system is usually the cause.  On long, multi-piece air intake systems be sure to check each of the connections for possible leaks. 

If the excessive wear is located at the bottom and the top of the cylinder bore, it is caused by dirt particles in the lubricating oil supply.  A PCV system that is open to the atmosphere, or a dipstick that is not properly seated is usually the cause.

Another indication of dirt contamination are vertical scratches on the face of the piston rings.  Scratches may also be found on the sides of the rings and on the ring lands.  Often the ring face edges become razor sharp.

                                                                        The AERA Technical Committee

          Double Lip Oil Seal Installation Information

Before installing any double lip oil seal, the groove between the
seal lips must be filled with a lubricant such Quaker State
multi-purpose kMoly Lubricant BLGT No. 2, Texaco 2301 RB, or
equivalent.

Failure to do this may result in dry running of the outer lip and
will cause seal failure.



                                     The AERA Technical Committee


September 1976 - SPB 34

##END##

                Revised Cylinder Head & Block On
               1987-Up Nissan 3.0L (VG30) Engines


Beginning with April, 1987 production, the cylinder heads and
block have been changed on Nissan 3.0L (VG30) engines. 
Improvements were made to increase power output and decrease
noise levels of the engine.

Revised production engines can be identified by an engine serial
number that ends in W, such as XXXXXX W.  Former engine serial
numbers end in either A or B.  However, factory service
cylinder blocks will not carry the W identification even though
they feature the improvements listed below.  A visual check is
necessary for proper identification.

Six new water galleries were added to the cylinder block (Figure
1) and the cylinder heads (Figure 2).  This change required a
modification of the cylinder head gasket, where the original 6
water holes were downsized and 3 new holes added on the exhaust
side of the gasket (Figure 3).  The revised cylinder head gasket
can also be identified by its differing identification tab. 
Figure 4 best illustrates the former and revised head gaskets.

Additional changes were made throughout the engine.  The pistons
now use full floating, larger diameter wrist pins.  The small end
bore of the connecting rod was increased to accept the larger
wrist pin.  The revised rod is also heavier than the former part. 
Again, components are identified by a W stamp. 

Nissan advises against the use of former parts when servicing
vehicles with engines manufactured as of April 1987.  Refer to
the chart to determine the proper component combination when
servicing engines manufactured prior to April 1987 (Figure 5).

For additional information see AERA Technical Bulletins: TB 601,
653 & 752


                                     The AERA Technical Committee


      Cylinder   Head     Cylinder   Short   Acceptable
        Head    Gasket      Block    Block   Combination

       Revised  Former     Former     N/A        Yes
       Former   Former     Revised    N/A        Yes
       Former   Former     Former     N/A        Yes
       Revised  Revised    Revised    N/A        Yes
       Revised  Former     Revised    N/A        Yes
       Revised  Revised    Former     N/A        No
       Former   Revised    Revised    N/A        No
       Former   Revised    Former     N/A        No
       Former   Former       N/A    Revised      Yes
       Revised  Revised      N/A    Revised      Yes
       Revised  Former       N/A    Revised      Yes
       Former   Revised      N/A    Revised      No




April 1991 - TB 761

##END##

                      Revised Crankshaft On
                   1984-87 Nissan VG30 Engines


Nissan has revised the snout of the crankshaft and related
service parts for VG30 engines manufactured after April 1987. 
Since only the revised crankshaft is being serviced by Nissan,
should it become necessary to use this crankshaft in 1984-1987
engines, several associated parts also need to be changed. 
Engines manufactured prior to April 1987 carry a serial number
that ends in either 'A' or 'B'.


Component                Prior to            As of
Description              April 1987          April 1987


Crankshaft               12201-02P80 1       12201-02P81 2
Bolt Spacer              Not Required        12308-V5321
Crank Pulley Bolt Washer 12308-V5000 3       12308-77A00
                         12308-V5001 3
                         12308-V5010 3
Crank Pulley Bolt        12309-V5000         12309-16V00


1    Does not include crankshaft pulley bolt washer or
     crankshaft pulley bolt.
2    Includes crankshaft bolt spacer, crankshaft pulley bolt and
     crankshaft pulley bolt washer.
3    Complete application information available on parts
microfiche


The front pulley assembly is the same for either crankshaft.


                                     The AERA Technical Committee


March 1991 - TB 752

##END##

                                  Revised Timing Components On
                                       1988 Nissan Z24I Engines
 
Nissan has revised the timing components used in 1988 and later Z24I engines.  The actual production change was instituted in January of 1988.  

The chain assembly was updated from a single roller to a double roller type.  This update requires a new crankshaft and camshaft sprocket as well as the new double roller chain.  The tensioner assembly and chain guides have not been changed.  Engines manufactured prior to January 1988 may be serviced with the new components as long as all three pieces are used.

                                                                         The AERA Technical Committee

       Driveability Complaints with Fuel Injected Engines

With the advances in electronic engine controls many consumer
driveability complaints have been eliminated.  However, since the
introduction of port or multi-point fuel injection (MFI) systems
new complaints are being heard.

Vehicles seem to perform well for some time after they are
purchased, but as the miles mount up some of the performance and
smooth operation of the engine goes away.  Since engines with MFI
are generally found in performance oriented automobiles, their
drivers will eventually notice the difference and seek out a
repair facility.

Reports from OE and other independent agencies are now detailing
that port fuel injectors are subject to residue accumulation at
the injector tip and pintle (see illustration below).  These
deposits cause uneven spray patterns and incomplete atomization
of the fuel, resulting in uneven idle, poor fuel economy,
increased emissions, hard starting and loss of power.

While there are many reasons for these deposits, there are
several cures available.  First and foremost is preventative
medicine.  Caution your customers to purchase a high detergent,
good quality gasoline that is advertised to contain detergents. 
Minor amounts of injector deposits may actually be removed with
these advanced blends.

However, there comes a time when a simple drive my engine clean
won't do the trick.  The aftermarket has developed several ultra
high detergent cleaners that can be run through the fuel
injection system to clean up larger deposits and return the
injector to normal operation.

Cleaning of the injectors is accomplished by disconnecting the
normal engine fuel supply lines and disabling the fuel pump on a
fully warmed up engine.  A pressure tank containing a mixture of
gasoline and 10 to 25% of cleaning detergent is connected to the
fuel rail.  The vehicle is restarted and about a gallon of this
mixture is run through the injectors at above idle speeds.  
 
Of course there are other methods that can be used to clean
injectors, the one detailed above is just one of them.  Consult
OE and aftermarket service manuals for additional information.


                                     The AERA Technical Committee


September 1988 - SB 160


##END##

                                                     Head Bolt Caution For 
                                         John Deere 300 Series Diesel Engines 

The AERA Technical Committee offers the following information about head bolt caution for John Deere 3179, 4239, 6359, 4276 & 6414 diesel engines. These engines are referred to as the 300 series, and use two different styles of head bolts.

Flanged-head cap screws do not require washers and provide for a tighter joint between the head and block. If your engine is not equipped with flange-head cap screws, replace all cap screws. Do not intermix flanged-head cap screws and non flanged-head cap screws within a given engine. Currently, only flanged-head cap screws are used in production and provided for service.

Early production cylinder block head bolt holes were counter bored down from the deck surface .118 (3.0 mm) and use standard bolts with washers; cylinder head cap screws MUST BE tightened using the conventional method as follows;

1st step 35 ft/lbs, 
2nd step 88 ft/lbs, 
3rd step 110 ft/lbs, 
4th step retorque cap screws after engine break-in. 

Late production cylinder block head bolt holes were counter bored down from the deck surface .370 (9.5 mm) and use cylinder head cap screws with built in washers. They must be tightened using the torque turn method as follows;
 
1st step 75 ft/lbs
2nd step 110 ft/lbs
3rd step Wait five minutes
4th step turn each bolt an additional 50° to 70° degrees  (No retorque required) 

Using either style bolts requires tightening the cap screws in a spiral rotation pattern starting from the center of the head and working outward to the ends.

Important; use only clean SAE 30 engine oil and remove excess oil from cap screws, do not use multi viscosity oil to lubricate cap screws.

                                                                               The AERA Technical Committe

                                                 Seized Camshafts On
                                        Nissan SOHC VG30 3.0L Engines

AERA has received reports of sudden camshaft seizures on Nissan SOHC VG30 3.0L engines.  This seizure is uncommon because the cause of the failure is a broken cylinder head bolt.  The head of the bolt breaks off and then becomes lodged under one of the cam lobes, resulting in the timing belt either breaking or stripping. 

If this type of failure occurs, removal of valve covers will reveal that the bolt head is lodged underneath the camshaft. Further engine disassembly is now necessary as this is a non-freewheeling engine.  Bent valves can be encountered on both cylinder banks, even if only one camshaft as seized.

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

                                                                         The AERA Technical Committee

                                         Timing Chain Guide Elimination On
                                         1991-93 1.6L DOHC Nissan Engines

The AERA Technical Committee has received information concerning the elimination of two timing chain guides on 1991-93 1.6L DOHC engines. Beginning with engines produced in March 1993, the top and left side timing chain guides were eliminated.

All replacement cylinder heads Part #11040-57Y01, will not have the drilled holes to attach the chain guides. Those guides are not necessary and may cause an undesirable rattling noise when the timing chain contacts the guide.  To prevent a possible noise complaint, Nissan suggests removing the two guides shown in the illustrations below anytime cylinder head repair is done.

                                                                               The AERA Technical Committee