INFO. ON SERVICING 2.0L OHV & 2.2L OHV CYLINDER HEADS

SUBJECT: INFORMATION ON SERVICING 2.0L AND 2.2L OHV CYLINDER HEADS WITH 7MM VALVE GUIDE PARTIAL CYLINDER HEAD ASSEMBLY

MODELS: 1987-94 CHEVROLET CAVALIER, BERETTA AND CORSICA 1994 OLDSMOBILE CUTLASS CIERA 1994 BUICK CENTURY

1994 CHEVROLET AND GMC S TRUCKS

1987 - 1994 CYLINDER HEADS WILL NOW BE SERVICED WITH A PARTIAL CYLINDER HEAD ASSEMBLY USING 7MM VALVE GUIDES. THE SERVICE CYLINDER HEAD PARTIAL ASSEMBLY WILL INCLUDE ALL THE VALVES (7MM VALVE STEMS), VALVE SPRINGS, VALVE KEEPERS, VALVE SPRING CAPS, SEALS AND SEATS.

THE 1987 - 1993 PRODUCTION CYLINDER HEADS USE AN 8MM VALVE GUIDE. THE 1987 - 1993 MODEL YEAR CYLINDER HEADS WILL NOW BE SERVICED WITH 7MM VALVE GUIDE CYLINDER HEADS. ADDITIONALLY, THE INTAKE VALVE SEAT ON THE 1987 - 1991 APPLICATIONS WAS 43MM (1.69"). THE NEW SERVICE CYLINDER HEAD HAS 44MM (1.73") INTAKE VALVE SEATS. THE 7MM VALVE TRAIN COMPONENTS LISTED ABOVE CANNOT BE USED ON A CYLINDER HEAD WITH 8MM VALVE GUIDES.

TECHNICIANS WILL HAVE TO TRANSFER THE ROCKER ARMS, ROCKER ARM BALL, ROCKER ARM STUD AND NUT, AND PUSH ROD GUIDE FROM THE OLD HEAD TO THE NEW CYLINDER HEAD.

A CYLINDER HEAD CORE HOLE PLUG WILL BE INCLUDED IN THE PARTS KIT. THE CORE PLUG WILL ONLY BE USED ON CAR APPLICATIONS. DO NOT USE THE CORE PLUG ON TRUCK APPLICATIONS. REFER TO FIGURE 1.

1987 - 1991 APPLICATIONS DO NOT USE A TEMPERATURE SENSOR IN THE LOCATION INDICATED IN FIGURE 2; INSTALL THE 1/8 X 27 PLUG INCLUDED IN THE KIT.

IF THE NEW 7MM VALVE GUIDE HEAD HAS BEEN PUT ON A PAST MODEL ENGINE, IT CAN BE IDENTIFIED BY THE CASTING NUMBER. THE HEADS WITH 7MM VALVE GUIDE WILL HAVE AN 'S' FOLLOWING THE 8 DIGIT CASTING NUMBER. ALL OTHER 2.0L OHV AND 2.2L OHV CYLINDER HEADS ONLY HAVE THE 8 DIGIT CASTING NUMBER. THIS NUMBER WILL BE LOCATED IN THE ROCKER ARM VALLEY UNDER THE VALVE ROCKER ARM COVER.

USE THE 1994 PARTS BOOK TO ORDER VALVE TRAIN AND CYLINDER HEAD COMPONENTS FOR ANY 2.0L/2.2L CYLINDER HEAD THAT HAS AN 'S' AFTER THE CASTING NUMBER. USE THE APPLICABLE 1994 SERVICE MANUAL FOR SPECIFICATIONS AND SERVICE PROCEDURES.

STARTING JANUARY 1994, CYLINDER HEADS WILL BE PRODUCED SO THE VALVE STEM SEALS FOR THE INTAKE AND EXHAUST WILL BE THE SAME. USE THE INTAKE SEAL PART NUMBER.

IF A CYLINDER HEAD WITH 7MM VALVE GUIDE IS ON THE ENGINE, THE 8MM VALVE GUIDE REAMERS (J 38847, J 38848 AND J 38849) MUST NOT BE USED. THERE WILL ONLY BE ONE OVERSIZED VALVE AVAILABLE FOR THE 7MM VALVE GUIDES. A NEW REAMER, J 38978, MUST BE USED TO OBTAIN THE .127MM OVERSIZE.

PARTS INFORMATION:

BEFORE ORDERING PART, CHECK AVAILABILITY OF ENGINE ASSEMBLY THROUGH CURRENTLY PUBLISHED ENGINE EXCHANGE PROGRAMS.

CYLINDER HEAD, PARTIAL ASSEMBLY

1987 - 1991 24574841 1992 - 1994 24574842

WARRANTY INFORMATION:

FOR VEHICLES REPAIRED UNDER WARRANTY, USE: LABOR OPERATION: J0518 - HEAD, CYLINDER - REPLACE USE PUBLISHED LABOR OPERATION TIME.

FIGURES: 2

GENERAL MOTORS BULLETINS ARE INTENDED FOR USE BY PROFESSIONAL TECHNICIANS, NOT A "DO-IT-YOURSELFER". THEY ARE WRITTEN TO INFORM THOSE TECHNICIANS OF CONDITIONS THAT MAY OCCUR ON SOME VEHICLES, OR TO PROVIDE INFORMATION THAT COULD ASSIST IN THE PROPER SERVICE OF A VEHICLE. PROPERLY TRAINED TECHNICIANS HAVE THE EQUIPMENT, TOOLS, SAFETY INSTRUCTIONS AND KNOW-HOW TO DO A JOB PROPERLY AND SAFELY. IF A CONDITION IS DESCRIBED, DO NOT ASSUME THAT THE BULLETIN APPLIES TO YOUR VEHICLE, OR THAT YOUR VEHICLE WILL HAVE THAT CONDITION. SEE A GENERAL MOTORS DEALER SERVICING YOUR BRAND OF GENERAL MOTORS VEHICLE FOR INFORMATION ON WHETHER YOUR VEHICLE MAY BENEFIT FROM THE INFORMATION.

COPYRIGHT 1994. GENERAL MOTORS CORPORATION. ALL RIGHTS RESERVED.