Cam Chucking Noise On
                                1989-95 Land Rover 3.9L VIN 2 Engines

AERA members have reported cam chucking noises on 1989-95 3.9L VIN 2 engines. This noise can be heard on both hot and cold temperature engines and is best observed at a front corner of the engine. The noise is most audible between idle and 2,000 rpm, while engine temperatures are hot. This noise also 
increases in frequency as engine speed increases. 

The cause of this noise has been determined to before and aft movement of the camshaft. The original design of this engine relies on cam lobe taper to 
control slight cam rearward pressure. Engines manufactured mid year during 1995 incorporated a cam button to control camshaft end play movement.

AERA members have reported installing the cam button, Part #CAM1000, and adjusting cam end play to reduce the likelihood of cam chucking noises. To install the button, follow the procedures listed below.

1. Remove old camshaft sprocket bolt and washer and  discard.
2. Obtain the revised bolt/button, Part#CAM1000, and new conical washer and carefully install into camshaft. Take care not to damage the nylon thrust  control button portion of bolt.
3. Use a deep well socket and torque to 41-44 ft./lbs.
4. Determine the clearance between button and cover by bolting on cover with a new mounting gasket attached. Using a plastic gauge strip will assist here.       5. The desired clearance specification is .005-.010 (.13-.25mm) for camshaft end play. Adjust end play by carefully flat filing the nylon button with a fine toothed flat file. The button/bolt should be mounted in a vise while performing this procedure.
6. Install gasket and front cover mounting bolts and torque bolts to 16 ft/lbs. 

                                                                        The AERA Technical Committee

                 Cylinder Head Specifications on
        Perkins Prima, Prima Marine & 500 Series Engines


AERA members should consider the following specifications when
remanufacturing Perkins Prima, Prima Marine & 500 Series
industrial cylinder heads.  These direct injection, high speed 4
cylinder diesel engines have also been distributed by Detroit
Diesel Corporation in various industrial and marine applications
since 1986 as well as British Leyland, Land Rover trucks.

The cylinder head minimum thickness should be no less than 4.718
(119.85mm).  According to Detroit it is possible to machine .008
(.20mm) from a new cylinder head casting before approaching
minimum thickness.

The valve recession should be maintained at .035 - .049 (.89 -
1.24mm) for both intake and exhaust valves.


                                     The AERA Technical Committee


June 1990 - TB 666

##END##

                           Valve Crosshead To Rocker Lever Clearance On
                              NH, NT & V-1710 Series Cummins Engines

Valve crosshead nose to rocker lever clearance on the subject engines must be checked during engine rebuild and at any time valve crossheads are replaced on engines using crossheads No. 123416 & 3000326. A minimum of .020 (.51 mm) clearance must be present as illustrated in Fig. 1, on the cylinder being checked with valves completely closed and crosshead in the upmost position. After installing rocker lever assemblies, check crosshead to rocker lever clearance as follows:

1. Turn crankshaft slowly in direction of rotation until the valves are closed on the cylinder being checked. With rocker lever held firmly against the stellite pad of the crosshead, a .020 (.51 mm) wire type feeler gauge must pass between the crosshead nose and the lower beam section of the rocker lever.

2. If the feeler gauge does not pass through:

a. Remove the rocker lever and/or crosshead and grind the nose of the crosshead or 	rocker lever beam in the area circled in Fig. 1 until enough clearance is obtained.

b. If the rocker is ground, grinding should cover the complete area illustrated in Fig. 2 in a continuous arc. Do NOT grind just the contact area.

Caution: A sharp depression in this area will cause a stress riser and eventual failure of the lever. Grind only enough material to achieve the required clearance. If grinding enters the oil passage, the rocker lever must be junked.

c. Grind sharp edges smooth.




                                                                   The AERA Technical Committee

Crankshafts Used In Industrial Applications On
GM (Chevrolet) 5.7L (350 CID) Engines

When the GM (Chevrolet) 5.7L (350 CID) industrial engine is used in some applications such as lift trucks, the only crankshaft that is applicable has the forging number 1182.  Dimension A of the rear flange is slightly smaller than that of other crankshafts used in General Motors 5.7L (350 CID) engines.

The larger flange crankshafts will not pass through the center hole of the bell housing.  This is very critical when an oil clutch system is used.

                                                                     The AERA Technical Committee

Burned Exhaust Valves, Low Power & Hard Starting On
Cummins NH & NT Engines With Jacobs Brake 25B & 30

Cummins Engine Co. reported that if the following complaints are experienced in the NH and NT engines equipped with Jacobs brakes, the slave piston clearance should be checked:

A. Exhaust valve burning

B. Low engine power when at operating temperature 

C. Engine hard to start or will not start at operating temperature

A standard slave piston adjustment of .018 +/- .001 has been established.  The .018 clearance setting is a cold setting which results in zero slave piston to crosshead clearance when the engine is at operating temperature.

Should the slave piston clearance setting be less than .018, the following conditions outlined in A, B or C above may result as well as affect breaking power.

If the slave piston clearance is greater than .018 +/- .001, the following problems may occur:

1. Engine injector train component problems
2. Injector carboning
3. Bent injector push rods
4. Worn injector adjusting screws
5. Decreased camshaft life
6. Cam follower and follower shaft failure
7. Delay in breaking action

If the above problems are experienced and the engine is equipped with a Jacobs brake, the slave piston clearance should be checked with the latest Cummins specifications.

                                                                     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