| OIL STARVATION OF THE CYLINDER HEAD |
Oil Starvation Of The Cylinder Head On
1986-89 Acura 1.6L Engines
AERA machine shop personnel are reminded to thoroughly clean the vertical oil passage in the cylinder block when rebuilding 1986-89 Acura 1.6L engines. This engine also uses an oil control jet at the block deck in that vertical oil gallery. It too must be removed, cleaned and free of obstructions. Note that the opening of the control valve is only .040 (1.02 mm) in diameter (see illustration).
Anytime the cylinder head is removed from the engine, the oil control jet needs to be removed from the gallery. Once removed the vertical gallery should be flushed from the lower oil supply gallery. Pressurized air will work if the engine has been disassembled. If the engine has not been removed from the vehicle, oil can be forced through the gallery by turning the engine with the starter. Be sure to install a new gasket under the control jet before positioning the cylinder head gasket and mounting the head.
Failure to reinstall the oil control valve will force too much oil into the cylinder head. This may render the valve seals ineffective or overwhelm the PCV system, causing excessive oil consumption.
The AERA Technical Committee |
| REVISED TIMING BELT TENSIONER FOR 2002-3 3.2L ACURA ENGINES |
Revised Timing Belt Tensioner
2002-2003 Acura 3.2L SOHC Engines
The AERA Technical Committee offers the following information regarding a revised timing belt tensioner for 2002-2003 Acura 3.2L engines. This tensioner is part of a product improvement by Acura. Vehicles with the revised tensioner should be identified by a punched mark above the sixth digit of engine compartment VIN Code as shown in Figure 1 below.
The original design timing belt tensioner is filled with oil to dampen oscillation. Due to a manufacturing situation, the tensioner oil can leak. If enough oil is lost, the timing belt loosens and causes engine noise. The worse case scenario is the belt may lose tension and allow loose of cam timing. Refer to the chart below to determine which vehicles are affected.
The AERA Technical Committee |
| SNAPPING NOISE ON 90-91 1.8L ENGINES |
Snapping Noise On
1990-91 Acura 1.8L Engines
The AERA Technical Committee has been advised of a snapping noise on
1990-91 Acura 1.8L engines. The best description for this noise is a sharp snapping sound, similar to the sound of spark plug wire arcing. The cause for this unusual noise is not obvious, but may be uneven cylinder head torque.
Inappropriate torque may permit the cylinder head to move as the engine reaches operating temperature. If this noise is detected and o other cause can be found, verify the cylinder head bolt torque with this procedure:
1. Allow the engine to completely cool and remove both camshafts.
2. In reverse sequence loosen cylinder head mounting bolts, one bolt at a
time, then torque each bolt immediately to 7 ft. lbs.
3. After all bolts have been tightened to 7 ft. lbs. in sequence, tighten all
bolts to 22 ft. lbs. Finally, advance the head bolt torque to 43 ft. lbs,
then 61 ft. lbs.
4. Reinstall the camshafts and adjust valve clearance to .006 for intake
valves and .007 for exhaust valves.
The AERA Technical Committee |
| ENGINE TICKING NOISE ON 3.2 & 3.5L ENGINES |
Engine Ticking Noise On
1999-2003 Acura 3.2 & 3.5L Engines
The AERA Technical Committee offers the following information regarding an engine ticking noise on 1999-2003 Acura 3.2& 3.5L engines. This noise occurs after the cylinder head has been removed for machining and reinstalled on the engine. The information contained in this bulletin applies to engines reassembled with original equipment head gaskets.
Inadvertently the incorrect cylinder head gaskets may have been installed on this engine. Some cylinder head gaskets were mispackaged with the incorrect cylinder bore diameter in the gasket. Instead of getting the correct 3.5040" (89 mm) bore gasket, gaskets with a 3.3858 (86 mm) bore were packaged for this engine.
The ticking noise that is heard is actually the pistons hitting the head gaskets as they approach top dead center (TDC). If the cylinder head gasket, as shown in Figure 1 below has a P8C stamped on it, the incorrect gasket was installed. The correct gasket should have the letters PGE stamped on it, Part #1255-PGE-A01.
Acura Part Numbers
Front Gasket Set Kit Part #06110-PGK-A11
Rear Gasket Set Kit Part #06120-PGK-A11
The AERA Technical Committee |
| OIL CONSUMPTION ON 86-94 ACURA 1.6, 1.7 & 1.8L ENG |
Oil Consumption On
1986-94 Acura 1.6, 1.7 & 1.8L Engines
The AERA Technical Committee offers information on oil consumption on 1986-94 Acura 1.6, 1.7 & 1.8L engines. Acura considers oil consumption when the rate is in excess of one quart to one thousand miles traveled. This engine uses a
metered oil supply to the cylinder head by means of a removeable metal oil jet located in the deck of the cylinder block.
The oil jet meters a certain amount of engine oil to the cylinder head components. During the removal process of the cylinder head, it may stick to the head and be misplaced during cleaning and handling. If the oil jet, Part
#15140PM3000, is not reinstalled during assembly, excessive amounts of engine oil will enter the cylinder head. This additional amount of oil will then collect under the valve cover and overwhelm the valve stem seals. The oil may also
enter the PCV system if the level becomes high enough. In either case, oil will enter the combustion process or the exhaust system causing oil loss.
Some AERA members increase the opening size of this orifice slightly, anytime the cylinder head has been removed from the block. Drilling the existing restrictor to .062 (1.575 mm) in size will increase the volume of oil to the cylinder
head and camshaft. That procedure has been beneficial during cold starts when ambient temperatures are very low.
Increasing the orifice hole size slightly should not overwhelm the cylinder head with oil, providing all other oil clearances are within specifications.
The AERA Technical Committee |
| 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 |
