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Mercury S-55 Engine Information
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The following technical bulletins were published by AERA.
 PISTON BORE CLEARANCE
                                 Piston To Bore Clearance Changed On
                                           Ford Products 2.3L Engines

Ford Motor Company updated Piston to Bore clearance limits to .0032 maximum for the 2.3L engines listed below:

Ford 1982-83 Mustang, Fairmont, Granada & LTD

Lincoln-Mercury 1982-83 Capri, Zephyr, Cougar & Marquis

Light Trucks 1983 Ranger

Note additional engine specifications below:

ENGINE SPECIFICATIONS
Ford Products 2.3L Engine

PISTONS AND RINGS

PISTON
Diameter
Coded Red 3.7780-3.7786
Coded Blue 3.7792-3.7796
0.003 Oversize 3.7804-3.7810
Piston-to-Bore Clearance (Select Fit) 0.0014-0.0022
Service Limit .0032 Max.
Pin Bore Diameter 0.9123-0.9126

Ring Groove Width
Compression (Top) 0.080-0.081
Compression (Bottom) 0.080-0.081                                                                             oil  0.188-0.19

PISTON PIN
Length 3.010-3.040
Diameter
Standard 0.9118-0.9124
0.001 Oversize 0.9130-0.9133
Piston-to-Pin Clearance 0.0002-0.0004
Pin-to-Rod Clearance Interference Fit


PISTON RINGS
Ring Width
Compression (Top) 0.077-0.078
Compression (Bottom) 0.077-0.078

Side Clearance
Compression (Top) 0.002-0.004
Compression (Bottom) 0.002-0.004
Oil Ring Snug Fit
Service Limit 0.006 Max.

Ring Gap
Compression (Top) 0.010-0.020
Compression (Bottom) 0.010-0.020
Oil (Steel Rail) 0.015-0.055


LUBRICATION SYSTEM

OIL PUMP
Relief Valve Spring Tension
(Lbs. Spec. Length) 15.2-17.2 @ 1.20
Drive Shaft-to-Housing 
Bearing Clearance 0.0015-0.0030
Relief Valve-to-Bore Clearance 0.0015-0.0030
Rotor Asmbly End Clear.(Assembled) 0.004 Max.
Outer Race-to-Housing Clearance 0.001-0.013                                                    l Capacity (Quarts U.S.) 4 (7)

FUEL PUMP

STATIC PRESSURE (PSI) (8) 5.0-7.0
MINIMUM VOLUME FLOW (9) (10) 1 Pint in 25 Seconds
ECCENTRIC TOTAL LIFT (Inches) 0.304-0.326

TORQUE SPECIFICATIONS-SPECIAL APPLICATIONS

ITEM SIZE Nm LB-FT
Auxiliary Shaft Gear Bolt 	M-10 38-54 28-40
Auxiliary Shaft Thrust Plate Bolt M-68-126-9
Belt Tensioner (Timing Pivot Bolt) M-1038-54 28-40
Belt Tensioner (Timing Adjusted Bolt) M-819-2814-21
Camshaft Gear Bolt M-128-96 50-71
Camshaft Thrust Plate Bolt M-6 8-12 6-9
Carburetor To Spacer Stud M-8 10-20 7.5-15
Carburetor To Spacer Nut M-8 14-19 10-14
Carburetor Spacer-To Manifold Bolt M-819-2814-21
Connecting Rod Nut (11) M-941-49 30-36
Crankshaft Damper Bolt M-14136-162100-120
Cylinder Head Bolt (12) M-12 108-122 80-90
Distributor Clamp Bolt M-1019-2814-21
Distributor Vacuum Tube To
Manifold Adapter 7-115-8
Exhaust Manifold To Cylinder Head
Bolt Stud Or Nut (13) M-1022-3116-23
Flywheel To Crankshaft Bolt M-1073-8756-64
Fuel Pump To Cylinder Block M-819-2814-21
Intake Manifold To Cylinder Head
Bolt Nut M-819-2814-21
Main Bearing Cap Bolt (15)M-12108-122 80-90
Oil Pressure Sending Wire To Block 11-248-18
Oil Pump Pickup Tube To Pump M-18 19-28 14-21
Oil Pump To Block M-819-28 14-21
Oil Pump Cover 10-15 90-130
Oil Pan Drain Plug To Pan M-14 21-33 15-25
Oil Pan To Block M-67-116-8
M-811-138-10
Oil Filter Insert To Cylinder Block 28-33 20-25
Oil Filter To Engine (16)
Rocker Arm Cover To Cylinder Head M-67-115-8
Spark Plug To Cylinder Head M-14 7-13 5-10
Temperature Sending Unit To Block 11-24 8-18
Water Jacket Drain Plug To Block 32-37 23-28
Water Pump To Block Bolt M-8 19-2814-21
EGR Valve To Spacer Bolt M-8 19-28 14-21
EGR Tube To Exhaust Manifold Conn. 13-149-11
EGR Tube Nut 13-149-11
Auxiliary Shaft Cover BoltM-68-12 6-9
Water Outlet Connection Bolt M-8 19-28 14-21
Cylinder Front Cover Bolt M-6 8-12 6-9
Inner Timing Belt Cover Stud M-819-28 14-21
Outer Timing Belt Cover Bolt M-68-12 6-9
Rocker Arm Cover Shield Bolt M-10 38-54 28-40
Thermactor Check Valve To Manifold 17 24-27 17-20
Fuel Filter To Carburetor 
Assembly-Bolt 9-11 80-100 Lb-In

NEW AND USED DRIVE BELT TENSION SPECIFICATIONS

Belts have differing tension specifications depending on whether they are Newly Installed (1) or Used (more than ten minutes of engine operation).  When belts are found to be below the allowable minimum they must be RESET (adjusted).  Specifications for these situations are shown below:

Belt Condition and Tension in Lbs.
Belt Type Installed Reset Limits
14V 50-80 40-60
All other V 120-160 90-120
V-Ribbed
4 Rib (Air pump only) 90-130 90-120
4 Rib 110-150 100-130
5 Rib 130-170 120-150
6 Rib (Fixed)140-180 130-160
6 Rib (With Tensioner) 85-14080-140

NOTE:  FIXED refers to systems with manually adjusted centers which are bolted in place and considered fixed.
(1) Newly Installed - Refers to the condition of the NEW drive belt before the engine has made no more than one rotation and before the belt has had a chance to stretch or seat into the pulley grooves.

(2) Time required for plunger to leak down 1/8 or travel with 50 lb. load leakdown fluid in lash adjuster.

(3) Distance in inches that front bearing is installed below front face of bearing tower.

(4) 0.002 undersize = Add 0.001 to Standard Thickness

(5) Pin bore and crank bearing bore must be parallel and in the same vertical plane, within the specified total difference when measured at the ends of an 8 bar - 4 on each side of rod centerline.

(6) Measured at the piston pin bore, centerline - 90 to the pin.

(7) Add one pint with filter change.

(8) On Engine, temperature normal, curb idle, in neutral, brakes set.

(9) Pump to tank return line pinched off, new fuel filter in line.

(10) Smallest Orifice = Not less than 0.220 I.D.

(11) Torque sequence in two steps:
Step 1 - 34-41 Nm (25-30 lb-ft)
Step 2 - 41-49 Nm (30-36 lb-ft)

(12) Torque cylinder head bolts in sequence in two steps:
Step 1 - 68-81 Nm (50-60 lb-ft)
Step 2 - 108-122 Nm (80-90 lb-ft)

(13) Torque in sequence in two steps:
Step 1 - 7-9 Nm (5-7 lb-ft)
Step 2 - 22-31 Nm (16-23 lb-ft)

(14) Torque in sequence in two steps:
Step 1 - 7-9 Nm (5-7 lb-ft)
Step 2 - 19-28 Nm (14-21 lb-ft)

(15) Torque in sequence in two steps:
Step 1 - 68-81 Nm (50-60 lb-ft)
Step 2 - 108-122 Nm (80-90 lb-ft)

(16) 1/2 turn after gasket contacts surface - oil gasket.

(17) Then rotate to position.

                                                                    The AERA Technical Committee
 ENGINE OVERHEATING OR LOSS OF COOLANT
                 Engine Overheating Or Loss Of Coolant With No Indication Of
                 External Leakage On 1975-77 Ford (Ford, Lincoln & Mercury)
                                                6.6L (400 CID) Engines

If coolant loss or overheating on the above engines is observed, this may be the result of a hairline crack at either side of the engine block on the tappet galley wall. The crack is usually found to be 4 - 5 inches in length located approximately 1 1/2 above the tappets between No. 2 & 3 or No. 6 & 7 cylinders.

Visual inspection of the rocker covers, oil dip stick, PVC valve inlet or breather cap will display accumulation of moisture deposits.

Remove the intake manifold and inspect the cylinder wall for a hairline crack above the tappets. A moisture deposit is usually evident at the crack area.

Pressure testing the cooling system for fifteen minutes with the intake manifold removed will positively identify the condition. 

                                                                              The AERA Technical Committee
 BURNED PISTON OR BROKEN RING LANDS
             Burned Pistons Or Broken Ring Lands On
                 Ford 1.6L (Except H.O.) Engines


Burned pistons or broken ring lands in 1981-82 Ford Escort and
1981-82 Lincoln-Mercury Lynx 1.6L (except H.O.) engines can be
the result of detonation caused by operating the engine with
insufficient coolant.

In these cases it is important to inspect the entire cooling
system before releasing the vehicle for operation.

While the engine is disassembled, check the cylinder head for
cracks and the head gasket surface of the cylinder block for
metal damage caused by engine overheating.

Inspect the gasket surface of the head for warpage, using a
straightedge.  If the head is warped, do not machine more than
.010 (.254mm) from the surface.

After reassembly, pressurize the cooling system and check for
leaks at all hose connections, the radiator and heater cores,
heater cross-over tube, water pump, and thermostat housing.

In addition check that the electric cooling fan is operating
properly and that the timing is set at specifications.


                                     The AERA Technical Committee


February 1984 - SB 109 


##END##
 OIL LEAK AT OIL PUMP
                                            Oil Leak At The Oil Pump On
                                             Ford 1981 Escort, 1982 EXP, 
                     Lincoln-Mercury 1981 Lynx & 1982 LN7 (1.6L) Engines

An engine oil leak at the oil pump on some 1981-82 Ford Escort & EXP and Lincoln Mercury Lynx & LN7 (1.6L engines) may be serviced by removing the external oil gallery pipe plug on the pump as shown below and applying Loctite(R)  Lock N' Seal(R) or equivalent to the plug threads.  Reinstall the plug and torque to 6-8 ft. lbs (8-12 N·m).

Ford Motor Company recommends the oil pump must be replaced if the gallery plug is found cross threaded, or if the outer surface of the gallery is cracked at the plug opening.

                                                                         The AERA Technical Committee
 EXCESSIVE OIL CONSUMPTION
                                          Excessive Oil Consumption On
                                                5.0L EFI Ford Engines

AERA members report excessive oil consumption on Ford 5.0L EFI engines.  This condition has been reported on both existing engines as well as engines that have been recently rebuilt.  
One very common source of oil consumption has been through the positive crankcase ventilation (PCV) system.  As the first step, verifying that the correct parts are used and are in good working order.  For most applications, the crankcase vacuum should be one to three inches of mercury (1 - 3 hg).

If the PCV system is working properly, check the rocker cover for a loose or deformed baffle.  The baffle is located in the right valve cover, directly under the PCV valve and may allow oil to collect in a puddle.  High vacuum will then pull the oil into the system.  Secure or reform the baffle to prevent oil from
collecting under the PCV valve.

                                                                         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
 BROKEN ROCKER ARM BOLTS
                                                       Broken Rocker Arms On
                                         Ford (Mercury) 5.8L (351 CID) Engines

Broken valve rocker arm bolts due to fulcrum to pedestal boss interference have been experienced in some Ford 5.8L (351 CID) Engines.

When encountering these trouble cases, check all remaining rocker arm bolts for breakaway torque turning the bolt clockwise, and checking all push rods for straightness. Bolts with breakaway torque under 20 ft.lbs. should be replaced using Part No. DOOZ- 6A527-A-5/16_18 x 1.38 bolt Grade 8 material.

All fulcrums in these problem engines must be reworked as follows: Grind and/or file the piloting chamfer edges as shown in the illustration, and remove all flared edges both on the side and bottom surfaces. If necessary buff or polish the sides of the fulcrum to ensure that it is free in the fulcrum channel.
 
To eliminate possible inaccurate torque readings caused by thread imperfections, lubricate the bolt threads and underside of the bolt head with engine oil. Assemble the rocker arm, fulcrum seat, bolt to the engine, and torque the bolts 20-25 ft.lbs. Then back the bolt out 4 full turns and retorque 20-25 ft.lbs. The rocker arm bolt torque has been revised from 17-23 ft.lbs. to 20-25ft.lbs.

To cut down on additional wear, mark the fulcrums so they can be installed in their original position and location in the rocker arms. Do not rotate the fulcrums 180°.
                                                                                The AERA Technical Committee