| REVISED TOP COMPRESSION RING |
Revised Top Compression Ring On
Navistar DT-466 Engines
In order to reduce engine emissions and crankcase blow by,
Navistar International has revised the top compression ring on
1990 DT/DTA-466 engines.
The top compression ring is now plasma coated on the face and
directly replaces the former chrome plated ring for all engines,
including those manufactured prior to the 1990 model year.
Intermixing of plasma coated and chrome plated rings in the same
engine is acceptable.
The revised ring can be identified by its foggy/grey appearance
and a white Dykem stripe. The former ring is bright in
appearance and is marked with a blue Dykem stripe. Markings
found on the side of the piston ring must be installed facing up
(see illustration).
The revised ring is only available as part of a piston ring
package which carries Part #1 810 358 C94 replacing Part #1 810
358 C93.
The AERA Technical Committee
July 1991 - TB 790
##END## |
| REVISED PISTON ASSEMBLY FOR 7.3L DIESEL ENGINES |
Revised Piston and Ring Assembly On
Navistar 7.3L Diesel Engines
Navistar International has revised the piston and ring assembly for their 7.3L engines used in Ford light and medium duty trucks among others. The new pistons and rings are used in all engines manufactured as of serial number 598754. Prior engines use the former designs. The new assembly may be used in sets to update older engines when they are being remanufactured.
The revised piston features a taller top ring and oil control ring groove to accommodate the new plasma ring set. Since the former design rings will fit into the new piston, a mix-up is possible. However, loss of oil control and poor engine performance may result.
Revised Design
Bore Piston & Ring Ring Set Stamped No. on
Size Assembly Part # Part # Piston
STD 1 813 167 C91 1 813 171 C91 1 813 154 C1
.010 1 813 168 C91 1 813 172 C91 1 813 155 C1
.020 1 813 169 C91 1 813 173 C91 1 813 156 C1
.030 1 813 170 C91 1 813 174 C91 1 813 157 C1
Former Design
Bore Piston & Ring Ring Set Stamped No. on
Size Assembly Part # Part # Piston
STD 1 809 140 C91 1 809 146 C91 1 809 107 C2
.010 1 809 141 C91 1 809 147 C91 1 809 108 C2
.020 1 809 142 C91 1 809 148 C91 1 809 109 C1
.030 1 809 143 C91 1 809 149 C91 1 809 110 C1
At present there are no aftermarket sources available for either the former and revised piston or ring set. Furthermore, pistons are only available as an assembly that includes the wrist pin, lock rings and piston rings. Piston ring sets are serviced separately.
The AERA Technical Committee |
| NEW GASOLINE ENGINE OIL CLASSIFICATION SH |
New Gasoline Engine Oil Classification SH
The American Petroleum Institute (API) has released a new gasoline engine oil category SH. Engine oils meeting this classification should be used in all 1994 and later gasoline engines. This oil may also be used in gasoline engines
manufactured before the 1994 model year.
As EPA emission laws continue to evolve, manufacturers of gasoline engines have been forced to follow tougher standards with lower total emissions. As those demands continue, engine oils have also required improvements. The oil classification SH, provides better protection against rust, oxidation, sludge,
varnish and extended component life expectancy.
Oils branded with the SH moniker are tested under the tougher Engine Oil Licensing and Certification System (EOLCS). This new system requires oil to pass either the first time tested, or pass on an average score of multiple samples tested. Previously oils could continue to be tested until passing results were generated.
Oils that pass the SH test and meet Energy Conserving II (ECII) requirements may use a new starburst logo indicating certification from the International Lubrication Standardization & Approval Committee (ILSAC). This new symbol is designed to allow consumers to readily identify oils that conform to the latest engine oil standards. Along with the starburst logo, the familiar API donut will display the oil's viscosity and SH classification. Oils not conforming to the ECII requirements may display the SH rating without the new starburst symbol.
The AERA Technical Committee |
| REVISED CONNECTING ROD |
New Connecting Rod Assemblies On
Navistar (International) DT-466 &
DT/DTI-466B Diesel Engines
A new 45° split line connecting rod assembly with a revised piston pin oil reservoir has been released for DT-466 & DT/DTI-466B diesel engines. The new connecting rod assemblies, which are not shot-peened, replace the old 35° assemblies starting with serial #32813 for the DT-466 engine and serial #75957 for DT/DTI-466B. The thread length of the connecting rod bolts has been
increased from 1.12 (2.84cm) to 1.70 (4.32cm) to facilitate the new design.
Old and new rods can be intermixed for engines in the field. New con rod bolts (676679C2) can be used in old con rod bolts, but OLD BOLTS (676679C1) MUST NOT BE USED IN NEW CON ROD ASSEMBLIES.
The AERA Technical Committee |
| INCORRECT THERMOSTAT ON 6.9L DIESELS |
Caution On Using Correct Thermostat On
International 6.9L Diesel Engine Including
Those In Ford Vehicles
International Trucks reports that thermostats in 6.9L diesel
engines are being replaced with will fit replacements, which
may cause premature cylinder head gasket failure due to engine
overheating. The overheating occurs because a flat washer
secured to the end of the power pill obstructs the bypass and
normal coolant flow passage. See illustrations below.
(Insert 2 Illustrations)
The AERA Technical Committee
April 1984 - SB 111
##END## |
| REVISED OIL SEAL CARRIER & GASKET FOR 7.6 & 8.7L DIESELS |
Revised Oil Seal Carrier & Gasket For
2000-2003 Navistar 7.6L & 8.7L Diesel Engines
The AERA Technical Committee offers the following information regarding a revised oil seal carrier and gasket for 2000-2003 Navistar 7.6 and 8.7L diesel engines. The revised components have proven to provide more effective sealing. Anytime the previous design paper gasket and flat flange oil seal carrier are removed, the revised components are recommended for use.
The new-machined groove in the oil seal carrier gasket flange, for push-in place seal, is more effective for sealing. The push-in place seal will ensure accurate alignment during assembly and adequate clamp load on the seal. A machined surface has been added to the bottom of the carrier to ensure a proper sealing surface for the oil pan.
Parts are currently only available from Navistar International with Part #1815699C3 for the oil seal carrier and Part #1741974C1 for the seal carrier gasket.
The AERA Technical Committee |
| CYLINDER HEAD SUBSTITUTION |
Cylinder Head Substitution On
Navistar (International) V-345 Engines
Cylinder heads used on the 1974 model V-345 Navistar (International) engines are manufactured with air injection ports. These air injection heads may be substituted for heads used on earlier V-345 engines which did not have air injection ports.
When supplied as a replacement head, the air injection head will be provided with plugs to seal the air injection ports where their use is not required. The plug part number is 328 285 CL.
Part numbers of the heads involved are:
New: 432091-C92 Old: 359490-C93
The AERA Technical Committee |
| REVISED CYL. HEAD GASKET ON 9.0L DIESEL ENGINES |
Revised Cylinder Head Gasket On
Navistar 9.0L Diesel Engines
Navistar International has released a revised cylinder head gasket for the 9.0L diesel engine.
The new head gasket features pre-applied sealant around the water ports. This new technique of gasket making provides increased sealing capabilities.
The new head gasket available by itself or as part of the upper engine gasket set.
Description New Part # Old Part #
Cylinder Head Gasket 489253C3 489253C2
Upper Eng Gasket Set 1701548C96 1700548C95
The AERA Technical Committee |
| CYLINDER HEAD - ENGINE FRONT COVER INTERFERENCE |
Left Cylinder Head Interference With Engine Front Cover On
DV-462B & DV-550B Navistar (International) Engines
It has been reported that in some instances the left cylinder head interferes with the engine front cover upon torquing the cylinder head bolts.
It is advisable to inspect the area shown in the illustration below when head gaskets are replaced on these engines. Interference in this area could prevent proper sealing of the gasket when specified torque is applied to the bolt.
To correct this condition, it is recommended that the cylinder head be removed and only sufficient stock be removed form the cylinder head to eliminate the interference condition.
The AERA Technical Committee |
| CYLINDER HEAD SPECIFICATIONS FOR 6.9L DIESEL |
Cylinder Head Specifications On
Navistar International 6.9L Engines
Due to the extremely close running clearances between the pistons and valves and the pistons and cylinder head, it is extremely important to maintain the proper specifications on this engine when performing cylinder head rebuilding operations.
The cylinder head thickness should be maintained between 4.795 and 4.805. Figure 1 shows that this measurement is taken from the deck surface to the valve cover rail.
Figure 2 shows the valve angles for the Navistar 6.9L engine. Notice that the exhaust valve angle is 37 1/2° while the intake valve angle is 30°. The valve seats have the same angles as the valves.
Again, due to very close running clearances, proper valve recession must be maintained. There is only .009 running clearance between the exhaust valve and the piston when the exhaust valve is fully open. The recession specifications are as follows:
Intake: .042-.054 (1.06mm-1.37mm) A and B models
Exhaust: .043-.055 (1.09mm-1.40mm) A models *
Exhaust: .046-.058 (1.17mm-1.47mm) B models *
* All exhaust valves serviced through Navistar are the B valves only, Navistar part #1 805 917 C1. Use the B specification with all new exhaust valves and the A specification on reused valves where applicable.
When reassembling the Navistar 6.9L cylinder heads, you must snap the valve stem seal onto the bottom of the valve spring retainer. Failure to do so may create coil bind.
The AERA Technical Committee |
