1987/06/29 Caterpillar

Recommendations For Reusability Of Pistons With Crater Rim Cracks{1214}

Usage:

3400 Family Of Direct Injection (DI) Engines With 7N3509, 8N1606, 8N1607, 1W9372, 2W865 Or 7W3668 Piston Body Assemblies

There have been some reports of cracking at the piston crater rim on the above engines. This problem may occur under extreme engine operating conditions. The fuel system and engine application should be checked on engines with piston crater rim cracks to make sure they are operating at the correct specifications.

Previously, Caterpillar recommended not to reuse a DI piston with crater rim cracks that were visible without the use of magnification. See Guidelines For Reusable Parts, Form SEBF8049, Page 15. Recent engineering lab tests now indicate that piston reuse is allowable on certain 3400 DI pistons. The allowable rim cracks can be located in ZONE A only and can extend a maximum of 5.0 mm (.20") downward or outward from the inside crater rim edge. See the illustration.

NOTE: This recommendation applies only to the 7N8509, 8N1606, 1W9372, 8N1607, 2W865 and 7W3668 Piston Body Assemblies used in the 3400 Family of Direct Injected Engines.

Allowable location and size of minor rim cracks.

Caterpillar Information System:

1987/06/15 Use Of Crankshaft Seal Adapter Eliminated {1150,1160,1161}

1987/06/15 All Three Main Bearing Part Numbers Stamped On Lower Portion Of Standard Size Bearing {1203}

1987/06/15 New Relief Valve Guide Used In Oil Pump Groups {1304}

1987/06/15 New 1U5230 Hand Pump (General Purpose Hydraulic) Available {0646}

1987/06/15 New 1U5752 Retainer Tool Available To Service Hydrostatic Transmissions {0721}

1987/06/15 1U5495 Latch Group Available For Earlier Large Duo-Cone Seal Installers {0700,4052}

1987/06/15 New Face Films For Electronic Monitoring System (EMS) Panels {7490}

1987/06/15 Caterpillar Original Equipment Paint Products (U.S. And Canada) {7559}

1987/06/01 Exhaust Manifold Thermocouple Has Longer Insulated Leads {1050,1408}

1987/06/01 Features And Servicing Of The Various Caterpillar 3161 Governors {1264,1278}

1987/06/01 Fuel Injector Trim Bolt {1257}

1987/06/01 Remanufactured Programmable Electronic Engine Controls (PEEC) {1250}

1987/06/29 New Water Pump Group Used{1361}

1987/06/29 Check For Shipping Plugs On The Inside Of New Pistons{1214}

1987/07/06 Testing Connecting Rod Eye Bushings When Overhauling Engines{1218}

1987/07/06 New Cylinder Head And Spacer Plate Gaskets Prevent Oil Leakage Around Gear Pocket{1101}

1987/07/06 Silicone Rubber Water Seals Available{1100}

1987/07/06 High Alloy Cylinder Head Improved{1101}

1987/07/06 3400 Engine Major Component Performance Guide Available{0374}

1987/07/06 New Power Takeoff Groups Used; New System Gives Better Face And Bore Runout On Front Power Takeoff Adapters{3050,3107}

1987/07/06 New Sealant Used On Oil Pan Mounting Bolts{1201,1302}

1987/07/06 New 1U5524 Adapter Cable Available For Use With 6V9060 Spark Timing Adapter Group And 8T5300 Engine Timing Indicator Group{0779,0781}

1987/07/06 New Electronic Modular Control Panel (SR-4 Generator Mounted){4450,7002}

1987/07/13 New Engines Rated @ 160 kW (210 hp) @ 2600 rpm Must Be Rerated When Used To Replace 2800 rpm Engines{0374}