| REVISED INTAKE MANIFOLD GASKET |
Revised Intake Manifold Gasket For
1989-97 Rover 4.0L Engines
The AERA Technical Committee offers the following information regarding a revised intake manifold gasket for 1989-97 Rover 4.0L engines. This information applies to engines built within the VIN codes listed below.
RANGE ROVER (LP) Up to VA367572
RANGE ROVER CLASSIC (LH) All
DISCOVERY (LJ) Up to VA725069 and VA558883
DEFENDER (LD) Up to VA115672
In a continuing effort to improve sealing around the inlet manifold, a new inlet manifold gasket and flat washers have been introduced into production. Vehicles built before the change, as indicated by the VIN codes above, can use the new style parts to repair inlet gasket leaks.
The new design gasket (Figure 1) and flat washers are designed to provide improved distribution of clamp load on the inlet manifold to cylinder head joints. As a result of the revised design, the sealing integrity of the joint is greatly improved.
The gasket design change can be easily identified as a change in the shape of the gasket around each inlet and coolant port opening. The installation of the new parts requires the correct torque procedure and must be followed with the new style gasket and flat washers. Refer to the numbered sequence in Figure 2 below to torque the mounting bolts.
1. Tighten clamp bolts at front and rear of gasket to 4-7 ft/lbs (5 -10 Nm). CAUTION: A flat washer must be used beneath all 12-bolt heads to ensure correct pressure is being applied.
2. Tighten the twelve intake manifold to cylinder head bolts in sequence (Figure 2) to 21 ft/lbs (30 Nm).
3. Wait! Allow gasket to bed in (set up) for at least 5 minutes.4. Tighten the twelve intake manifold to cylinder head bolts in sequence (Figure 2) to 35-40 ft/lbs (47-54 Nm) using a standard torque wrench.
5. Tighten clamp bolts at front and rear of gasket to 14-20 Nm (10-15 lb. ft.).
The AERA Technical Committee |
| CAM CHUCKING NOISE ON 1989-95 3.9L VIN 2 |
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 |
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## |
| REAR MAIN BEARING REUSE GUIDE |
Rear Main Bearing Cap Re-Use Guide For 6V-53
Detroit Diesel Allison Engines
Detroit Diesel Allison reported that the discovery of a crack in
the rear main bearing cap of a 6V-53 naturally aspirated or
turbocharged engine does not automatically mean that the cap
should be scrapped. It may be used if the crack occurs on the
bearing shell inside of the dowel pin holes.
The illustration below shows the types of cracks which may be
found on the 6V-53 rear main bearing cap and whether the cap is
re-usable.
(insert illustration)
1. Cap can be re-used. Crack occurs on the bearing shell side
of the dowel pin holes.
2. Cap cannot be re-used. Crack occurs on both sides of the
dowel pin hole, extending toward the bearing shell area and
the cap bolt hole.
3. Cap cannot be re-used. Crack occurs at a location other
than the dowel pin hole.
A prefinished rear main bearing cap with machined thrust washer
surface (part no. 5199147) is available. After replacing the
bearing cap, the block must be align bored to insure proper
alignment.
The AERA Technical Committee
November 1983 - TB 295
##END## |
| VALVE CROSSHEAD CLEARANCE |
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 |
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| CRANKSHAFTS INDUSTRIAL |
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 |
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-RINGS |
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 COOLANT |
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 |
