New Piston Groups Use Keystone-Type Piston Rings And Have Improved Design Of Valve Pockets
Usage:
D348, D349 Engines
Description of Change: A change has been made to the rod and piston group used in the above models. A new basic piston group is used, which has a new piston body of an improved design. The design improvements are:
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- ... Keystone-type piston rings are now used. These piston rings have better resistance to deposits which can prevent free operation of the rings. Free operation of the rings will give a good seal for longer service life.
- ... The valve pockets machined into the top of the piston are now symmetrical (the same on both sides of the piston). With this design improvement, it is no longer necessary to have a mark on the piston for installation in a specific position. The new pistons can be installed either way in the cylinder. Formerly, it was necessary to install the pistons with the V-mark on the piston in alignment with the V-mark on the spacer plate.
- ... A relief (machined notch) is cut between the valve pocket and the outside diameter of the piston. This will prevent possible damage to the cylinder liner and the piston head land in some conditions of operation.
- ... Keystone-type piston rings are now used. These piston rings have better resistance to deposits which can prevent free operation of the rings. Free operation of the rings will give a good seal for longer service life.
Adaptable As: Direct replacement.
Caterpillar Information System:
1978/12/13 New Exhaust Valve Has Improved Three-Piece Construction
1978/12/13 A Washer With Closer Tolerances Is Now Used In The Governor And Fuel Pump Drive Group
1978/12/13 New Hose Has More Resistance To Heat
1978/11/15 5P8690 Fixture Group And 5P8691 Socket Are Available For Easier Reconditioning Of 5M4169 Cam Followers
1978/11/15 New Fuel Injection Nozzles Are Used In 3208 Truck Engines When Equipped With EGR
1978/11/15 Tips For Service Information Retrieval System (SIRS) Users
1978/11/15 Improvement Made To Solenoid In Electric Shut-Off Group
1978/11/15 New Transmission Mounting Group Has Improved Design For Longer Service Life
1978/11/15 New Control Cover Gives Better Control Of Exhaust Gas Recirculation System
1978/10/18 Salvage Of Turbocharger Compressor Housing During Reconditioning
1978/10/18 A New 5P9698 Frequency Calibrator Is Available For The Calibration Of Caterpillar Diagnostic Tools
1978/10/18 4J7533 O-Ring Seals Now Available For Parts Service Of The 5P4150 Nozzle Tester Group
1978/12/13 Single Coil Shut-Off Solenoid Used In Place Of Dual (Two) Coil Shut-Off Solenoid
1978/12/13 Sender Unit For Engine Oil Pressure Gauge Moved To New Location On Truck Cab
1978/12/13 New Coolant Temperature Regulator Has Flat Washer-Type By-Pass Valve
1978/12/13 List Of Service Publications
1978/12/13 New Design Brace Used In 4N2905 Air Cleaner Group
1978/12/13 90° Elbow Added To Air Cleaner Group To Prevent Damage To The Air Filter Service Indicator
1978/12/13 New Electric Service Meter Used
REWORK HMSO (HYDRAMECHANICAL SHUTOFF) ON D379B D398B D399 IN ALL APPLICATIONS IF SO EQUIPPED PI7004 WORLDWIDE REWORK HMSO (HYDRAMECHANICAL SHUTOFF) ON D379B D398B D399 IN ALL APPLICATIONS IF SO EQUIPPED PI7004 WORLDWIDE
PSP FOR INSTALLING NEW FUEL RATIO CONTROL ON 3306 DI-TA TRUCK ENGINES PS0160 WORLDWIDE EXCEPT BRAZIL COSA SENT TO TRUCK TEPS PSP FOR INSTALLING NEW FUEL RATIO CONTROL ON 3306 DI-TA TRUCK ENGINES PS0160 WORLDWIDE EXCEPT BRAZIL COSA SENT TO TRUCK TEPS
PRIORITY:INSTALLING GEAR-TYPE OIL PUMP; INSPECT OUTPUT SPLINES AND CONTROL VALVE PIP965 US AND ALL AMERICAS PRIORITY:INSTALLING GEAR-TYPE OIL PUMP; INSPECT OUTPUT SPLINES AND CONTROL VALVE PIP965 US AND ALL AMERICAS
PRIORITY:RETIGHTEN CRANKSHAFT COUNTERWEIGHT BOLTS; REPLACE BOLTS IF NECESSARY 3508, 3512 ENGINES - PI3005 - MAILED US AND CAN ADA, CACO, COFA, CFEL, BRAZIL, COSA PRIORITY:RETIGHTEN CRANKSHAFT COUNTERWEIGHT BOLTS; REPLACE BOLTS IF NECESSARY 3508, 3512 ENGINES - PI3005 - MAILED US AND CAN ADA, CACO, COFA, CFEL, BRAZIL, COSA
PARTIAL CREDIT AVAILABLE FOR SALES OF VALVE SPRING PRODUCT UPDATES FOR CERTAIN 3208 N/A ENGINES PI7007 WORLDWIDE (IN CLUDING ALL TEPS) EXCEPT COSA, BRAZIL SEE JUNE 27,1983 SERVICE LETTER PARTIAL CREDIT AVAILABLE FOR SALES OF VALVE SPRING PRODUCT UPDATES FOR CERTAIN 3208 N/A ENGINES PI7007 WORLDWIDE (IN CLUDING ALL TEPS) EXCEPT COSA, BRAZIL SEE JUNE 27,1983 SERVICE LETTER