| | REVISED HEAD BOLTS ON M/B ENGINES | Revised Head Bolts On
1984-93 Mercedes Benz 2.2L, 3.0L, 3.5L Diesel Engines
The AERA Technical Committee offers the following information regarding revised head bolts on 1984-93 Mercedes Benz 2.2L, 3.0L, and 3.5L Diesel engines. To allow for an increase in the torque preload for the cylinder head bolts, the bolts have been modified with an increase in tensile strength.
Mercedes Benz started the change in the bolts with the following engine numbers.
Engine As Of Engine End Number
602.962 005247
603.970 000260
When cylinder head replacement is necessary on any 602.96, 603.96 and 603.97 turbo diesel engine, the previous head bolts must be discarded and replaced with the modified head bolts.
The modified head bolts can be identified by the following information along with the head bolts shown in Figure 1. Previous head bolts had a bolt head diameter of 20.7 +/- .3 mm and a code number of 85 or 850. Modified head bolts have a head diameter of 21.2 +/- .3 mm with a code number of 95 or 950 and also two ribs on the bolt head as shown in Figure 2.
Head bolts can be purchased under the following part numbers.
Part # Length
603 990 01 10 80 mm (3.1496")
603 990 02 10 120 mm (4.7244")
603 990 03 10 115 mm (4.5275")
The AERA Technical Committe | | REVISED LINER & UPPER LINER SEAL | Revised Liner & Upper Liner Seal On
Mercedes Benz OM 401 through 447 LA Diesel Engines
Mercedes Benz has revised the cylinder liner and upper liner seal on their OM 401, 402, 403, 407, 421, 422, 423, 424, 441, 442, 443, 444, 447 LA diesel engines.
The revised cylinder liner features a reduced shoulder, measuring .3898-.3898 (9.90-9.92mm), to accommodate a metallic Tombac upper seal ring and single O ring (Figure 1).
The former liner's ledge measured .3957-.3965 (10.05-10.07mm) and required two O rings and silicone sealer (Figure 2).
The counterbore depth of .3969-.4000 (10.08-10.16mm) of the cylinder block has not changed, leaving liner protrusion unchanged at .0012-.0036 (.03-.09mm). The revised and former liners are completely interchangeable as long as the proper upper seal is used. Only the revised liner will be serviced in the near future.
The AERA Technical Committee | | ENGINE FAILURE | Engine Failure On 1978-89 Mercedes Benz 3.0L Diesel Engines
The AERA Technical Committee offers the following information regarding engine failure on 1978-89 Mercedes Benz 3.0L diesel engines. This failure has been reported on vehicles with high mileage or shortly after a partial engine repair.
The damage reported has ranged from lack of compression to catastrophic component failures. The cause of these failures has been related to a lack of tension on the engine?s timing chain, allowing piston to valve contact. The reason for insufficient tension on the timing chain is a broken chain tensioner spring. See Figure 1 below to view one such spring that broke shortly after the cylinder head and tensioner were re-installed. The spring fatigued and broke after the outside diameter of the coil wire had worn excessively.
The timing chain tensioner requires removal and re-installation anytime the cylinder head is removed. It is therefore advised to replace this spring, Part # A1109933901 anytime the tensioner is removed.
The AERA Technical Committee | | CYLINDER BLOCK SLEEVES FOR 84-89 4.2 & 5.0L ENGINES | Cylinder Block Sleeves For
1984-99 Mercedes Benz 4.2 & 5.0L Engines
The AERA Technical Committee offers the following information regarding installation of aluminum sleeves in 1984-99 Mercedes Benz 4.2 & 5.0L, 116, 117 and 119 engines. This information should be used anytime cylinder bore over sizing is considered. This aluminum engine block requires a special honing procedure for the aluminum bores.
Mercedes Benz now offers an aluminum cylinder sleeve to the repair cylinder bores. These sleeves should only be installed and machined/honed by a machine shop that is capable of carrying out this kind of work to Mercedes-Benz specifications. Below is a chart showing the machining dimensions to install the new sleeves in the above-mentioned engines. It should also be noted that there are six sleeves for those engines and two outside diameters. After the sleeves are installed they can be sized to fit standard or + .5mm oversize pistons.
Machining Dimensions For Block
Basic Bore for Aluminum Sleeve 95.500-95.535 mm 100.000-100.035 mm
Basic Bore for Sleeve Collar 97.500-=97.535 mm 402.000-102.035 mm
Counterbore Depth for Sleeve 4.400-4.450 mm 4.400-4.450 mm
The AERA Technical Committee | | CRANK COUNTERWEIGHT BALANCE WEIGHT REMOVAL & INSTALL | Crankshaft Counterweight Balance Weight Removal & Installation on
Mercedes 280 (110 Series) Engines
Removing the front balance plate from Mercedes Benz 110 engine
series crankshafts can be quite difficult, especially since the
balance plate is riveted to the crankshaft.
AERA members have developed a procedure that is safe and cost
effective:
1) With a 3/8 end mill, remove the head of each of the four
rivets that attach the plate to the counterweight.
2) Simultaneously drive all four rivets out of the crankshaft
to prevent distortion of the plate.
3) Refinish the crankshaft as required.
4) Install the plate by pressing 4 new rivets, Mercedes Benz
Part No. 000661 006013 through the counterweight and into the
plate.
5) Hold the plate to the crankshaft counterweight by wedging a
5/8 or 3/4 bolt, cut to length, between the second
counterweight and the plate. Position the cap screw end of each
bolt right underneath the plate countersink. This will mushroom
the end of the rivet, securing the plate.
The AERA Technical Committee
September 1990 - TB 692
##END## | | FLYWHEEL SPECIFICATIONS | Flywheel Specifications
The AERA Technical Committee suggests referring to the following
flywheel specification chart when re-surfacing flywheels.
Type of
Manufacturer Flywheel Specs Comments
_________________________________________________________________
Allis Chalmers Cup 1.437 D17,D19,190XT
Tractors
AMC Cup .125 2.5L (GM engine)
Alpha Romeo Cup .878
BMW Step .013-.015 320i
Caterpillar Cup 2.937 +/-.005 #9N2646 Cast Number
Chrysler/Mitsubishi Cup .600-.605 2.0L DOHC, #9801
Cast Number
Chrysler Cup 1.00 3.7L engine
Cummins Cup 2.925
Cummins Cup 2.937 2 piece clutch
DDC Flat 1.582 8.2L, Minimum
thickness
Fiat, Spider Step .018 1600 engine
Ford, Falcon Cup 1.00 6 Cylinder engines
Ford, Courier Cup .285
Ford Cup .310
Ford, Ranger Cup .003 V6 Cylinder engines
Ford Truck Cup 1.500 534 CID Truck
Ford Truck Flat .965 New Thickness
Ford Cup 1.140-1.160 Model A
GM, OHC Brazilian Flat .750 New Thickness
GM Cup .125 2.5L, & Vega
GM, Buick Cup .125 V6 Engines
GM, Spirit Cup .195
GM, Sprint Cup .1969 Chevrolet/Suzuki
Honda Cup .030 Small cup
Honda Cup .030 #K4SC16AG Cast
Number
Honda Cup .100-.104
Honda Cup .785 Long alignment pins
Honda Cup .900 Short alignment pins
Honda, Accord Cup .615 1986
Hyundai, Excel Flat Mitsubishi engine
Isuzu Cup .010-.017 Trooper, Pup
Isuzu, Diesel Cup 1.691-1.695 6BD1, 6BDT engines
Mack Midliner Flat 1.260 Min. Measure from
crank/mount to disc
Mazda Cup .062 RX2 Rotary engines
Mazda, RX7 Cup .310
Mazda, 2.2L, 1987 Cup .785 Hyd. Clutch,
Segmented wheel
Mazda, 2.0L Cup .805 Hyd. Clutch, .020
max/removal
Mercedes, 240D Cup .885
Navistar, 404/446 Flat .750 New thickness
Navistar, 6.9L Flat 1.410 Minimum thickness
Navistar 9.0L Flat 1.585 Minimum thickness
Nissan Flat With groove
Nissan, Maxima Flat With groove, #425
Cast Number
Nissan, (Datsun) Step .003-.005 No groove
Nissan,
(Sentra,Stanza) Step .006-.010 1.6L & 2.0L engines
Nissan, B2000 Cup .807 new Max stock removal
.020
Nissan,(Datsun)240Z Step .010 With groove
Renault Step .021 1.4L Alliance
Saab, 96 Cup .656
Subaru Cup .830 Justy
Subaru Cup .875
Subaru Cup .905 4X4 Brat
Suzuki Cup .070
Suzuki Cup .197 1.0L, 3 cyl
Toyota Step .018-.022 Large alignment pins
Toyota, 22RE Step .018-.022 #627 Cast Number
Toyota Cup .055 Small cup
Toyota Cup .965-.970 Tercel, large cup
Toyota Step .040 Tercel, step
Toyota Step .020 Land Cruiser
VW Cup .945 Air cooled, 6 Volt
VW Cup .913-.918 210MM Clutch
VW Cup .830-.835 Rabbit/Golf/Scirocco
Vanagon Cup .982 Water/Air cooled bus
engine
VW Cup .830 Air cooled engine
VW Cup .885 Air cooled engine
Specifications listed for Step type flywheels refer to the
height of the wear surface above the pressure plate mounting
surface. Specifications for Cup type flywheels refer to the
height of the pressure plate mounting surface above the wear
surface.
The AERA Technical Committee
June 1992 - TB 677R
(Please destroy TB 677)
##END## | | CHILLED IRON CAMSHAFT ON 2.6L M103 ENGINES | Chilled Iron Camshaft On
1987-91 Mercedes Benz 2.6L M103 Engines
The AERA Technical Committee offers the following
information on a chilled cast iron camshaft for 1987-
91 Mercedes Benz 2.6L M103 engines. Beginning in March
of 1989, these engines received a chilled cast iron
camshaft and rocker arms with carbide inserts. This
change was done as a product improvement and
intermixing previous and revised components is not
recommended.
To identify engines with the revised components, the
manufacturer has stamped an S into the exhaust side
of the cylinder head as shown below. Updating previous
cylinder heads with the revised components is advised,
and those heads should also be stamped to reflect the
revised components. Below is a list of parts required
to incorporate this change.
Component Part Number
Camshaft 1030506401 (Code #53)
Rocker Arm 1030501033
Ignition Dist.
Rotor Bracket 1031580840
Optional 1031580740
Torx Head Screw 1039900122
Camshaft Gear 1030520601
Cam Gear Mounting Bolts 1039900022
AERA is currently unaware of an aftermarket source for
these components and they are available only from the
manufacturer.
The AERA Technical Committee
February 1998 - TB 1545
##END## | | MEASURING INSTALLED VALVE STEM HEIGHT | Measuring Installed Valve Stem Height For
1992-95 Mercedes Benz 3.2L DOHC Engines
The AERA Technical Committee offers the following information on measuring installed valve stem height for 1992-95 Mercedes Benz 3.2L DOHC engines. The method of measuring the installed stem height for this engine is not made in the conventional manner. According to Mercedes Benz, the prescribed method to measure is from the tip of each valve to the camshaft-bearing base (camshaft housing bore).
To correctly measure the intake and exhaust installed valve stem heights; lay a 6mm diameter bar onto the base of the camshaft bearing bores. Measure the distance at dimension ?T" as shown in Figure 1 below, using a caliper and record for all locations. Refer to chart below for specifications for the intake and exhaust installed valve stem height.
Location Standard ?T" Dimension Repair Limit ?T" Dimension
Intake .953-.974" (24.21-24.75mm) .943-.965" (23.96-24.51mm)
Exhaust .874-.896" (22.21-22.75mm) .865-.886" (21.96-22.51mm)
If, during checking the specifications against the recorded values and any measurement are under repair size, you must install new valve seats and/or valves in the head. These new seats and/or valves will help to properly position the hydraulic lash compensators for their correct operation.
Caution: Do not use a magnetic tool to remove the bucket type cam followers. If a magnetic tool is used and the buckets retain even a small amount of magnetism, the buckets may attract metal particles within the oil supply. Which, may cause possible camshaft lobe and follower failure.
Note: Dimension (H) shows a reference for a new head height of 5.350-5.354 (135.89-135.992 mm). The minimum head height is 5.335 (135.509 mm).
The AREA Technical Committee |
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