SENSOR GP-PRESSURE 1638530 - Caterpillar

All 3408, 3408B and 3412 EnginesSUPPLEMENT: 03/10/86SERVICE MAGAZINE, JULY 1, 1985, PAGE 3. "New Cylinder Heads And Fuel Nozzle Adapters Used".Put a mark through the last paragraph in the DESCRIPTION OF CHANGE section. The correct information follows: All former engines, not listed in Charts A and B, use either the 4W5733 Adapter Assembly shown in Illustration 3 or the earlier 2W9757 Adapter Assembly shown in Illustration 4. These engines use a capsule-type fuel injection nozzle. The 2W9757 Adapter Assembly was canceled and replaced by the 4W5733 Adapter Assembly.
Illustration 4. Capsule-type fuel injection nozzle with 55.12mm (2.170") adapter bore.--------------- END SUPPLEMENT ---------------Reference: Service Magazine, October 15, 1984, Page 2, New High Alloy Material Is Used In Cylinder Head Assemblies. Service Magazine, April 1, 1985, Page 4, New Compression Washers (Gas Seals) Used On 7000 Series Fuel Injection Nozzles.
Description of Change: Changes have been made to provide stronger cylinder heads on 3408, 3408B and 3412 Engines. The new cylinder heads are made from a high alloy material. See the October 15, 1984 reference article. The diameter of the fuel nozzle adapter bore in the new cylinder heads is 40.45 mm (1.593"). The former cylinder heads had a fuel nozzle adapter bore of 55.12 mm (2.170"). These changes will provide much stronger cylinder heads and reduce the possibility of cylinder head cracking.
Illustration 1. The 7000 Series Fuel Injection Nozzle with 40.45 mm (1.593") adapter bore.A new fuel nozzle adapter is used to fit the smaller bore in the new cylinder heads. The new 7W1645 Adapter holds the nozzle in place with a 7W2315 Retainer that threads onto the top of the adapter. See Illustration 1. This eliminates the former clamps. See Illustrations 2 and 3.
Illustration 2. Former 7000 Series Fuel Injection Nozzle with 55.12 mm (2.170") adapter bore.
Illustration 3. Capsule-type fuel injection nozzle with 55.12 mm (2.170") adapter bore.The new compression washer (gas seal) is used between the fuel nozzle and fuel nozzle adapter. See the April 1, 1985 reference article for the correct seals.
The new 7000 Series Fuel Injection Nozzle (Illustration 1) is identical to the former fuel injection nozzle (Illustration 2) except for a 15/16" recessed hex on the top of the nozzle. The former nozzle had a 7/8" hex which was not recessed. The recessed hex allows the 7W2315 Retainer to fit over the nozzle and seat correctly. The former nozzle cannot be used with the new 7W1645 Adapters. The nozzle with the recessed hex will fit and is the parts service replacement for both arrangements shown in Illustrations 1 and 2.
All former engines, not listed in Charts A and B, use the nozzle adapter and clamps shown in Illustration 3. These engines use a capsule-type fuel injection nozzle.
Adaptable As: The new cylinder head assemblies, fuel nozzle adapters, and fuel nozzle assemblies are in effect on the engines shown in Chart A [40.45 mm (1.593") adapter bore, 7000 Series Fuel Injection Nozzle, Illustration 1]. Only the engines in Chart B can be adapted to the new parts. This