| The following technical bulletins were published by AERA. |
| | UNDERSIZE CRANKSHAFTS IN PRODUCTION ENGINES | Undersize Crankshafts On
Some Lincoln Continental 7.5L Engines
Some .010 undersize crankshafts were used in production on 7.5L (460 CID) Engines Lincoln Continental engines including the Mark III. These engines can be identified by the letter M and/or P (indicating main or crankpin journal) stamped on the right front of the cylinder block near the engine date code stamp. The back of the bearings in the engines involved are stamped .010 U.S.
The AERA Technical Committee | | MAIN BEARING KNOCK | Front Main Bearing Knock On
Some 1975-1977 Ford, Lincoln, Mercury 7.5L (460 CID) Engines
It has been reported that some 1975-1977 Ford, Lincoln and Mercury 7.5L (460 CID) engines may have a front main bearing knock. The thump or knock may be distinctly heard inside the vehicle at half engine frequency when the engine is hot and is most noticeable between 800 and 1500 rpm.
Ford engineers recommend checking the engine timing. Following this move the vehicle outdoors, close the windows and shut off all accessories. Slowly raise engine speed to 1500 rpm in drive while depressing the brake pedal. If the front main bearing is defective, a definite recurring thump will be heard at half
crankshaft frequency.
To solve the noise problem, Ford Motor Company has recommended selective-fit standard and undersize bearings:
Upper main bearing (Std.)
Upper main bearing (.001)
Upper main bearing (.002)
Lower main bearing (Std.)
Lower main bearing (.001)
Lower main bearing (.002)
Any combination of the above main bearing halves can be used. The use of two different size halves on one journal is approved, however, the larger undersize should be installed in the upper position. A properly selected combination of bering halves should allow for a free-turning crankshaft when all bearing cap
bolts are correctly torqued to specifications.
Installing these selective-fit bearings should enable you to provide .0004 to .0015 clearance at the front main bearing. Try the .001 undersize bearing first and check the clearance with Plastigage or equivalent.
The AERA Technical Committee | | EXCESSIVE PREIGNITION ON HSC ENGINES | Excessive Pre-Ignition On
Ford 5.0L HSC Engines
AERA members have reported instances of severe pre-ignition (ping) with some Ford 5.0L (302 CID) engines using High Swirl Combustion (HSC) cylinder heads.
On the HSC cylinder head, part of the casting extends into the combustion chamber area between the intake and exhaust valve (Figure 1). This protrusion has an extremely sharp edge that can actually start to glow, causing pre-ignition of the air fuel mixture.
Ford recommends grinding the sharp point off the casting, smoothing out any sharp corners to prevent new hot spots (Figure 2). Do not remove more than necessary or compression will be lowered to a point where the vehicle will no longer idle.
The HSC cylinder head carries the casting number E6SE and can be found on some 1986 and 1989 Ford and Lincoln Mercury vehicles.
The AERA Technical Committee | | PUSHRODS OF VARYING LENGTHS | Pushrods Of Varying Lengths On
Ford (Ford, Lincoln & Mercury) Engines
It has been reported that, due to manufacturing variances and the use of non-adjustable rocker arms, some Ford engines equipped with hydraulic valve lifters may have pushrods of different lengths installed in the same engine. The pushrods may be standard length, 1/16 longer than standard or 1/16 shorter than standard.
Rebuilders are cautioned that it is extremely important that pushrods be returned to their original positions when reassembling these engines. Failure to do so may result in excessive clearances, causing valves to be held open.
To check for this condition, the procedure is as follows: With the valve closed, apply pressure to the pushrod side of the rocker arm until the hydraulic lifter is bottomed out, then measure the clearance between the rocker arm and the valve tip with a feeler gauge. If this clearance exceeds the manufacturer's specifications, the longer pushrod must be used; if the clearance does not meet the minimum specification, the shorter pushrod must be used. For correct valve clearance specifications, refer to the Ford Service Manual, Motor Manual, Chilton's, etc.
Note: On engines which have machined in any way which alters the original valve train geometry, all push rods must be checked for correct length.
The AERA Technical Committee | | FLYWHEEL & CRANKSHAFT CAUTION | Caution On Flywheel, Crankshaft & Damper On
Some 1981 Ford (Lincoln-Mercury) 5.0L (302 CID) Engines
Ford Motor Co. announced that some 1981 Ford (Lincoln-Mercury) engines are manufactured with a 1980 crankshaft, flywheel and damper. These engines may be identified by a decal having a red S on a white background, located on the left hand rocker cover.
The new 1981 flywheel, crankshaft and damper cannot be used on the 1980 engines unless all three components are replaced as a unit. Otherwise, engine vibration may result.
1981 engines may be identified by a daub of green paint on the flywheel, crankshaft and damper.
The AERA Technical Committee | | METRIC & ENGLISH FASTENERS | Comparison Of Metric And English System Fasteners
Background Information
The information presented here will help you to have a better understanding of Metric fasteners and how they stack up with the more familiar English (Inch) types.
For one thing, more and more Metric type fasteners are being used in the assembly of American made vehicles. The Automatic Overdrive Transmission is no exception. All of the bolts, nuts and machine screws used in the A.O.T. are Metric.
Identification
When it is necessary to replace a Metric fastener (bolt, nut, screw, stud, etc.) ALWAYS choose the correct Metric replacement and NOT the English (Inch) type. They are not interchangeable! Of course, this also holds true for installing a Metric fastener when the English (Inch) size and type was used originally.
Both types of fasteners (Metric/English) are easily identified with markings or numbers which indicate the strength of the fastener. These markings are described below. Attention to these markings is important in assuring that the proper replacement fastener is used in service.
Note: English system and Metric system fasteners are available through local Ford and Lincoln-Mercury Parts Departments.
Bolt Identification
*The property class is an Arabic numeral distinguishable from the slash SAE English grade system.
**The length of all bolts is measured from the underside of the head to the end.
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 | | | | | 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 |
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