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

                                 Coolant In The Engine Oil Supply On
                                           1991-93 BMW 1.8L Engines

AERA members have reported coolant in the engine oil supply on 1991-93 BMW 1.8L engines. The cause of this condition may be the result of a deteriorated front cover gasket and/or the erosion of the timing cover mating surfaces. That leakage may allow engine coolant to pass around the gasket and enter the engines oil supply. This condition may also show evidence of external coolant leakage at the engine's front timing cover aera. 

In most instances, if the cover is leaking externally, it is also leaking internally. Ignoring a slight amount of external leakage, may lead to extensive engine damage if it is also leaking internally.

Vehicles built after approximately 10/1/93, have a revised optimized rubber material composition and reduce the possibility of this problem occurring. 

To repair a metal erosion condition, BMW authorizes the use of a metal epoxy type repair to the gasket mating surfaces of either the cylinder head or timing cover. Many AERA shops have been successfully welding those areas.

                                                                        The AERA Technical Committee

                                      New Cylinder Liner O-Ring Seals On
                                      Cummins NH/NT 6 Cylinder Engines

Cummins Engine Company has released new O-ring seals for the cylinder liners in NH/NT 6 cylinder engines.  The new seals are made of an EP material and have a smaller diameter cross-section.

The new seal replaces both the old center seal #3008998 and the old lower seal #183049.  The new seal carries Cummins part #3032874 and is black in color with one blue dot.

The new O-ring seals are not to be intermixed with the former seals on the same liner.  Cylinder liner deformation will result.  You can use the former seals and new seals in the same engine as long as they are used in the correct combinations on each liner.  The illustration below shows the correct combinations.

                                                                       The AERA Technical Committee

                                               Oil in Cooling System on
                                         VW 1.5L & 1.6L Diesel Engines

AERA members have reported instances of engine oil in the cooling system on VW 1.5L diesel engines.  According to AERA sources, the problem is related to a crack in the cylinder head bolt hole located near the oil gallery feeding the cylinder head.

The oil feed gallery in the block is located on one side of the center head bolt hole and a coolant jacket is on the opposite side of the bolt hole.  Pressurized engine oil is diverted through a slot in the head gasket and is feed up the side of the head bolt to the cylinder head.  The oil also follows the bolt back down to the bottom of the bolt hole.  Should the crack in the head bolt hole extend to the coolant jacket, oil can mix with engine coolant.

This problem is generally found on engines equipped with 11mm head bolt holes.  Later design engines utilize 12mm head bolts and do not exhibit this defect.  At the time of this writing no successful repair procedure is available.

                                                                       The AERA Technical Committee

                                        Cylinder Head Specifications on
                                              Case 207 Diesel Engines

The following cylinder head specifications should be considered when remanufacturing Case Model 207 diesel engine cylinder heads.

The minimum cylinder head thickness has been established at 3.968 with a new head measuring 4.000 +/- .005.  Heads are measured from the deck surface to the rocker cover rail.

Valve recession should be checked and adjusted if necessary to a maximum recession of .015, below the deck surface, for both intake and exhaust valves.  Valves on new cylinder heads are generally flush with a +/- .005 tolerance.

                                                                       The AERA Technical Committee

                                         Main Bearing Saddle Repair Kits

The Cummins Engine Company has made main bearing saddle repair kits available for several engines.  These kits can be used to salvage cylinder blocks when a main bearing has spun and the main bearing saddle has been damaged.

Each kit contains an 1/8 drill bit, two hold down bolts (one for the lock ring and one for the other side of the saddle), a quantity of rivets and the appropriate number of repair sleeves.  Semi-finished or good used main bearing caps are also needed to complete the repair.

A main bearing saddle can be successfully repaired by following this procedure.
                                                                                                                            Remove the main bearing cap from the saddle to be repaired.  Using the appropriate align bore tooling remove .050 of material out of the saddle.  This will enlarge the main bearing bore by .100.

Clean the saddle and lock tang area.  Install the repair sleeve and align the lock tang slot of the sleeve with the one in the block.

From the repair kit, install the washer marked L on the lock tang side of the saddle.  Install the second washer on the opposite side.  Install the hold down screws and torque to 20 lbs.ft. (Figure 1).

Mount the 1/8 drill bit in a right angle drill, so that the drill extends 1/4 beyond the chuck jaws.

Using the 4 holes in the repair sleeve as a guide, drill through each of the holes into the saddle.  The proper hole depth is achieved when the chuck jaws contact the repair sleeve.

Clean the 4 holes and install the supplied rivets (Figure 2).  Peen the rivets until they are flush with the repair sleeve.

Remove the temporary hold down bolts and trim the ends of the repair sleeve so they are flush with the main bearing saddle.

Clean the main bearing bolt holes and install a good used or semi-finished main bearing cap.  Torque the main bearing bolts to specifications.

Using the appropriate align boring tools, refinish the main bearing housing bore to specifications.  Approximately .050 of material should be removed from the repair sleeve.
                                                                             
Main bearing bore repair kits or sleeves may also be available from several aftermarket sources.

                                                                        The AERA Technical Committee

                          Overheating Of Engines With Electric Cooling Fans

Ever since gasoline prices have shot up, vehicle manufacturers have downsized cars and their engines.  One of the best ways of making a car smaller is to turn the engine sideways under the hood.  This has instituted the use of one or more electric cooling fans to move air through the radiator.  Diagnosing overheating conditions on engines with electric cooling fans requires a few extra steps to ensure that the electrical control system for the fan is operating properly.

o    Perform all of the tests associated with normal
     installations, for example:  check antifreeze level,
     thermostat, water pump and hoses.

o    Check that the cooling fan is moving air through the
     radiator.  With the fan turned on air should never blow out
     through the front of the vehicle.  If there is more than one
     fan, be sure to check both.  It's possible for the
     electrical leads to be reversed during installation causing
     the fan to move air in the opposite direction.

o    If the vehicle is equipped with two fans, be sure that both
     of them work.  If the vehicle is equipped with air
     conditioning, one of the fans may only operate when the air
     conditioning is on.  Consult the service manual if you are
     not sure.

o    Fans are controlled by a temperature sending unit.  Check a
     suspected faulty sensor by bridging the two connections.  If
     the fan comes on, then the sensor is at fault.

o    Verify that the fan comes on at the temperature listed in
     the service manual.  Replace the sensor if the proper
     temperatures are not maintained.

For additional information see AERA Technical Bulletins: TB 706,
SB 158 & SB 137

                                                                         The AERA Technical Committee