1985/04/01 Caterpillar


Changes To Turbocharged Truck Engines For 1985

Usage:


3208 Truck Engines (2Z)

The basic engine arrangements for 3208 Truck Engines (2Z) have been changed for 1985. The changes have been made so the engines will meet 1985 emission requirements. The changes include new governor and fuel injection pump groups. Also changed are the piston and rod groups, turbocharger groups and fuel pump drive groups on some engines.

The new governor and fuel injection pump groups have new fuel injection pump assemblies. The new parts are shown in Charts A and B.


Illustration 1. Orificed delivery valve (ODV).

The fuel injection pump assemblies have an orificed delivery valve (ODV). See Illustration 1. In the past, pump assemblies used a reverse flow check valve (RFC) as shown in Illustration 2.


Illustration 2. Reverse flow check valve (RFC).

The new ODV performs the same functions as the RFC with fewer parts. They both give protection against continuous fuel flow from the fuel transfer pump to the cylinder caused by a cracked or broken fuel injection nozzle. Both (ODV and RFC) bleed the fuel pressure pulses, that occur between injections, back to the fuel transfer pump.

The static timing for the fuel pump and governor groups used in these engines is shown in Chart C.

Some engine arrangements use new governor and fuel injection pump drive groups. The new drive groups have a different timing advance than the former drive groups. See Chart D.

The new fuel lines groups contain new fuel lines and new fuel injection nozzles. The new fuel lines have a larger inside diameter of 1.83 mm (.072 "). The part numbers for the new fuel lines are shown in Chart E. The new fuel lines can be identified by notches on the nuts used in the fuel line assemblies. An example of the notched fuel line nut is shown in Illustration 3.


Illustration 3. Notched nuts used on new fuel lines.

A new 4W7016 Fuel Injection Nozzle Assembly is used in the turbocharged 3208 Truck Engine for 1985. See Illustration 4.


Illustration 4. New 4W7016 Fuel Injection Nozzle Assembly.

Fuel enters the new fuel injection nozzle assemblies from the top. See Illustration 4. The fuel line on the new fuel injection nozzle assembly is formed to go over the top of the rocker shaft of the valve mechanism. This will allow the fuel injection nozzle assemblies to be removed without removing the rocker shaft.

NOTE: The line assembly and adapter must not be re moved from the nozzle assembly.

Some engine arrangements have replaced their former high compression ratio (18.2:1) rod and piston groups with lower compression ratio (17.5:1) rod and piston groups. See Chart F.

Chart G shows the new turbocharger groups used in the new engines.

The model year of the engine is listed on the emissions decal on the valve cover. The engine or engine parts should not be modified in any way. Parts for 1984 and earlier engines are still available.

Caterpillar Information System:

1985/03/01 What Cost Failure
1985/03/01 Installation Of Heli-Coils In Holes With Damaged Threads
1985/03/01 List of Service Publications
1985/03/01 Internal Seals In 7000 Series Fuel Injection Nozzles Cannot Be Replaced
1985/03/01 A New Book "Analyzing Diesel And Natural Gas Engine Valve Failures " Is Available
1985/03/01 3208 Truck Engine Service Manual Available In Spanish
1985/03/01 New Service Manual Binders Are Made From Thicker Material
1985/03/01 New Crankshaft Seal Groups Used
1985/03/01 Dowtherm 209 Full-Fill Coolant
1985/03/01 New Service Tools Available
1985/03/01 Cross Link Between Fuel Racks Has Smoother Surface
1985/03/01 Do Not Weld On Painted Surfaces
1985/04/01 Changes To Naturally Aspirated Truck Engines For 1985
1985/04/01 Use Of Fuel Injection Timing Information In The "Fuel Setting And Related Information" Microfiche
1985/04/01 Hardened Spacers Help Keep Bolts Tight
1985/04/01 New Compression Washers (Gas Seals) Used On 7000 Series Fuel Injection Nozzles
1985/04/01 Changes To Exhaust Manifolds Help Prevent Broken Studs
1985/04/01 Check Cylinder Block And Head Flatness Whenever There Is A Head Gasket Failure
1985/05/01 Check For Interference Between Water Temperature Regulator And Cylinder Head Bore
1985/05/01 Be Sure Correct Piston Rings Are Used On 3400 Series Engines
1985/05/01 Visual Inspection Can Detect Chrome Plated Engine Valves
1985/05/01 Information For Ordering Kpa Or Dual Scale Gauges
1985/05/01 New Bearing Housings Available For Turbochargers
1985/05/01 Constant Torque Hose Clamps Available For General Use
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