Continental Refrigerator IO-240-A, IO-240-B Installation And Operation Manual
IO-240-A
CONTINENTAL® AIRCRAFT ENGINE
B
INSTALLATION
AND
OPERATION
MANUAL
FAA APPROVED
Publication OI-6
©
2011 CONTINENTAL MOTORS, INC. OCT 2011
Supersedure Notice
This manual is a revision of the Continental Motors IO-240 Operation and Installation Manual, Part No. X30620,
released on January 1996. Upon FAA Approval, this manual supersedes X30620 in its entirety.
Effective Changes for this Manual
0..........31 October 2011
List of Effective Pages
Document Title: IO-240 Series Engine Installation & Operation Manual
Publication Number: OI-6 Initial Publication Date: 31 October 2011
Page Change Page Change Page Change Page Change
Cover............................0
A...................................0
i-xii................................0
1-1 thru 1-10.................0
2-1 thru 2-32.................0
3-1 thru 3-30.................0
4-1 thru 4-28.................0
A-1 thru A-4..................0
B-1 thru B-10................0
C-1 thru C-20 ...............0
Published and printed in the U.S.A. by Continental Motors, Inc.
Available exclusively from the publisher: P.O. Box 90, Mobile, AL 36601
Copyright © 2011 Continental Motors, Inc. All rights reserved. This material may not be reprinte d, republished, broadcast, or o therwise
altered without the publisher's written permission. This manual is provided without express, statutory, or implied warranties. The publisher will
not be held liable for any damages caused by or alleged to be caused by use, misuse, abuse, or misinterpretation of the contents. Content is
subject to change without notice. Other products and companies mentioned herein may be trademarks of the respective owners.
A IO-240 Series Engine Installation & Operation Manual
31 October 2011
Service Document and Technical References
Technical information in the service documents listed below relevant to the engine models
covered by this engine manual have been incorporated in the manual. The full content of active
Continental Motors engine service documents is available http://continentalmotors.aero. Refer to
Section 1-3, “Contact Information” for Continental Motors web site details.
Service Document Subject Affected Chapter
M64-18, Turbocharger Field Conversion Engine Modification N/A
M72-17R1, Maximum Weight Difference Allowance Between
Connecting Rods and Pistons in the Same Engi ne
M73-13, Reaming and Bushing Rocker Shaft Bosses
M75-6R1, Conversion of Engines From One Model to Another Engine Configuration N/A
M76-4, Installation Of Propeller Shaft Or Nose Oil Seals Oil Seal Replacement N/A
M76-5R1, Remote Mounted Oil Coolers
M76-8, Intake Valve Change
M76-15, Fuel Pumps
M77-19, Intake and Exhaust Rocker Arm Identification and
Application
M81-8R1, Fuel Pump Screen Restriction
M81-25, Exhaust Flange to Cylinder Installation Procedures Engine Installation N/A
M86-9, Crankcase Modification Engine Overhaul N/A
M87-15, Alternator Ground Strap Alternator Replacement N/A
M88-9, Lightning Strikes Unscheduled Maintenance 4
M88-10, Contaminated Fuels Unscheduled Maintenance 3 & 4
M89-7R1, Engine Operation after Cylinder Replacement and/or
Major Overhaul
M89-9, Excessive Crankcase Pressure Unscheduled Maintenance 4
M89-18, EGT Recommendations EGT Leaning 4
M90-9, New TCM Magneto and Harness Applications
M90-13, Exhaust Valve Stem Corrosion/Erosion Inspection & Overhaul N/A
M90-17, Crankcase Inspection Criteria Inspection N/A
M91-4, Piston Identification and Piston Ring Application Bulletin Piston Replacement N/A
M91-9, Cam and Lifter Lubrication during Rebuild Overhaul N/A
M93-8, Rocker Arm to Rotocoil Clearance Rocker Arm Clearance N/A
M93-10, TCM Ignition Systems Service Bulletin 639 Inspection N/A
SIL93-11A, New Service Document Format Service Documents 1
MSB93-12, Valve Retainer Key Installation Inspection Inspection N/A
SIL93-14, CFC Compliance N/A N/A
Engine Assembly and
Overhaul
Cylinder Repair and
Overhaul
Engine Installation and Oil
Servicing
Engine Maintenance and
Overhaul
Fuel Pump and Camshaft
Replacement
Engine Assembly N/A
Fuel Pump Inspection and
Parts Replacement
Engine Operation-break-in 4
Magneto and Ignition
Harness Replacement
N/A
N/A
N/A
N/A
N/A
N/A
N/A
IO-240 Series Engine Installation & Operation Manual i
31 October 2011
Service Document Subject Affected Chapter
SIL93-15, General Practices for Installation of Lock Wire, Tab
Washers, and Cotter Pins
CSB94-1, TCM Ignition CSB641 Magneto Coil N/A
SIL94-5, Mobil AV-1 Oil Authorized Lubricants N/A
MSB94-8D, Magneto to Engine Timing Service N/A
SB95-2, Inspection and Maintenance of Engine Control Cables
and Linkage
SB95-3B, Alternator/Generator Drive Couplings Inspection N/A
CSB95-4, Intake Valve Guide Seal Inspection N/A N/A
SIL95-5, Hose and Tubing Installation Hose and tubing installation Appendix C
CSB96-1, Starter Gear and Clutch Assembly, P/N 653575 Starter Replacement N/A
SID96-6, TCM Ignition SB653
SB96-7C, Torque Limits fastener torque Appendix B
MSB96-10, Requirements for Ultrasonic Inspection
SB96-11B, Propeller Strikes and Hydraulic Lock Scheduled Inspection 4
SB96-12, Continued Airworthiness for TCM Cylinders Scheduled Inspection N/A
SIL97-1, Airworthiness Limitations Airworthiness Limitations N/A
SID97-2B, TCM Cylinder Warranties N/A N/A
SID97-3E,Procedures and Specifications for Adjustment of TCM
Continuous Flow Fuel Injection Systems
SID97-4C, Cylinder Bore and Piston Fit Specifications Overhaul & Service Limits N/A
SB97-6B, Mandatory Replacement Parts
CSB97-10A, Piston Pin Plug Wear Service Limits N/A
SIL97-14, Replacement Cylinder Assembly Cylinder Replacement N/A
SB97-15, TCM Ignition Service Bulletin SB660 N/A N/A
CSB98-1B, Intake and Exhaust Valve Inspection Service Limits N/A
SIL98-9A, Time Between Overhaul Periods
SIL99-1, Engine Preservation for Active and Stored Aircraft
SIL99-2C, Current Listing of Sealants, Lubricants and Adhesives
Authorized by TCM
SB99-8, Engine Fuel Injection System Preservation
SB00-3A, Crankshaft, Counterweight and Connecting Rod
Repair Information
SB00-4A, Australian AVGAS Contamination Inspection and Operation N/A
SIL00-7A, Oil Gauge Rod Application Oil Servicing N/A
SIL00-9A, Engine Data Plates N/A N/A
SB00-10, Fuel Pump Seal Fuel Pump Installation N/A
Standard Practices Appendix C
Inspection N/A
Engine Operation-Hot
magneto Test
Crankshaft Removal &
Replacement
Engine Operational Check
and Engine Specifications
Engine Inspection &
Assembly
Engine Specifications,
Scheduled Maintenance
Engine preservation and
returning an engine to
service after storage
Materials Throughout
Fuel Injection system
storage
Repair Specifications N/A
4
N/A
3, 4
Appendix C
2
3
3
ii IO-240 Series Engine Installation & Operation Manual
31 October 2011
Service Document Subject Affected Chapter
SIL00-11B, Release of new Cylinder Induction Port Drain
Connector
CSB02-8, TCM Ignition Systems CSB664 N/A N/A
SIL03-1, Cold Weather Operation – Engine Preheating Preheating procedures 4
SIL03-2B, Currently Active Approved Spark Plug Application Spark plugs 2 & 3
SIL03-3, Differential Pressure Test and Borescope Inspection Inspection Criteria N/A
SIL03-7, IO-240 Series Magneto Drive Gear Inspection Criteria N/A
SIL04-2, Cylinder Barrel Ultrasonic Inspection N/A N/A
SB04-4, Manifold Valve Spring Replacement Overhaul Repairs N/A
CSB04-5A, TCM Ignition Systems CSB665A Magneto Service N/A
SB04-10, Piston Pin Marking Overhaul Repairs N/A
SB04-11, Valve Guide Application, Installation and Reaming Valve Guide Repairs N/A
SIL04-1A, Installation of Optional Altitude Compensating Fuel
Pump on IO-240-B Series Engines
SIL04-8 Optional Replacement Starter fo IO-240 Series Engines
SIL04-9, IO240B13B Manifold Valve Replacement, Heat Isolation
Modifications, and Throttle Body Modifications
SIL04-12A, TCM Authorized Engine Adjustments, Component
Replacement and Repositioning
SID05-1, Design, Operation and Maintenance of TCM Camshafts
and Hydraulic Lifters
SB05-2, Overspeed Limitations Unscheduled Maintenance 4
SIL05-3, Engine Specification Numbers Engine Specification 2
SIL05-4A, IO-240 Series PN 656850 Inline Fuel Filter Installation
and Inspection Procedures
SIL05-5A, IO-240-B Series Manifold Valve Fuel Scavenge
System Installation
SIL05-6A, IO-240-B Series Product Upgrades
SB07-1, Connecting Rod Piston Pin Bushing Inspection Inspection N/A
SB07-3, Procedures and Specifications for adjustment of TCM
IO-240-B17B Fuel Injection System installed on Diamond DA20C1 Aircraft
SB07-8, Recommended Minimum RPM & Manifold Pressure
Cruise Operations Limits
SB08-3A, Throttle & Mixture Control Arms N/A 4
SB08-4, Fuel Injection System Contamination
SB08-8, Slick Service Bulletin SB2-08 Magneto Inspection N/A
SB08-9A, Slick Service Bulletin SB3-08A Magneto Inspection N/A
Cylinder Assembly N/A
Fuel System Specification
and Engine Operational
Check
Engine Specification and
Parts Replacement
Engine Specification 3, 4
Engine Specification N/A
Inspection Criteria N/A
Engine Specification,
Inspection, Component
Replacement
Engine Specification,
Inspection, Component
Replacement
Engine Specification,
Inspection, Component
Replacement
Engine Specification,
Inspection, Component
Replacement
Engine Operation 4
Engine Specification,
Inspection, Replacement
3, 4
3, 4
3
3
3
3 & 4
3
IO-240 Series Engine Installation & Operation Manual iii
31 October 2011
Service Document Subject Affected Chapter
SB08-13, Induction System Hose and Clamp Installation
SB09-14, Camshaft Corrosion Treatmen Engine Inspection N/A
SIL640, Service Document Format Service Documents Preface & 1
SB643B, Maintenance Intervals for TCM Bendix Magnetos Inspection & Operation N/A
SB653, Hot Magneto Test Inspection & Operation 3 & 4
Induction System
Inspection & Assembly
Appendix C
Service Documents Released After Publication
Continental Motors strives to provide clear, concise, and accurate information and instructions
based on best known engineering data at the time of publication. Ongoing process improvements
may change a specification or procedure after a manual is released. Service documents, defined in
Chapter 1, expedite customer notification and serve as the prevailing instruction over conflicting
information until the new information is incorporated in the manual text. As service documents
are received, note the service document number , releas e date, title, a nd applicable sec tion af f ected
by the service document in the blank cells below and insert a copy of the service document behind
the last page of this section. Make pen & ink corrections, where appropriate, to the original text in
the manual with a citation to the service document; i.e. see SB9X-1. For paragraphs or entire
sections, draw an “X” through the affected information in the manual and reference the service
document containing the correction.
Service Bulletins Release After This Manual
Bulletin Number: Release Date:
Title:
Bulletin Number: Release Date:
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Bulletin Number: Release Date:
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iv IO-240 Series Engine Installation & Operation Manual
31 October 2011
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IO-240 Series Engine Installation & Operation Manual v
31 October 2011
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PREFACE
Continental Motors provides Instructions for Continued Airworthiness based on the design,
testing, and certification of engines and parts for which Continental Motors is the holder of the
Type Certificate (TC) or Parts Manufacture Approval (PMA) issued by the Federal Aviation
Administration (FAA). Instructions in Continental Motors engine manuals, which include
maintenance, repair limits, overhaul, and installation, are applicable only to engines and parts
supplied by Continental Motors.
Except for F AR part 43.3 authorized owner preventive maintenance, Continental Motors ICAs are
written for exclusive use by FAA (or equivalent authority) licensed mechanics or FAA (or
equivalent authority) certified repair station employees working under the supervision of an FAA
licensed mechanic. Information and instructions contained in this manual anticipate the user
possesses and applies the knowledge, training, and experience commensurate with the
requirements to meet the prerequisite FAA license and certification requirements. No other use is
authorized.
Installation of aftermarket parts on a Continental Motors engine constitutes a deviation from FAA
approved type-design criteria. Continental Motors has not participated in design, test, or
certification of any aftermarket parts. Continental Motors does not provide product manufacturing
specifications to aftermarket parts manufacturers and accepts no liability for the suitability,
durability, longevity, or safety of such parts installed on Continental Motors engines. Installation
of aftermarket parts on a Continental Motors engine must be performed using Instructions for
Continued Airworthiness prepared by the manufacturer and accepted by the FAA for the subject
installation. Continental Motors ICAs must not be used for such parts.
Service documents may contain general information or information specific to a group of engines
or be in effect for a limited time frame. Service Documents may also contain advance changes to
the ICAs. It is the responsibility of the organization/person maintaining or operating the engine to
verify that current and complete information, including Service Documents, FAA Airworthiness
Directives (ADs), and publications are used.
To facilitate the use of current data, Continental Motors provides information on the Continental
Motors web site. The information available includes a listing of the latest manual versions,
service documents, FAA ADs, and other information applicable to the ICAs.
Manuals published since 2003 are available on the Continental Motors web site to Fixed Base
Operators (FBOs) who subscribe to Continental Motors Internet Services. Information available
to Continental Motors engine owners is also available to FBOs. Printed manuals and service
subscriptions are also available. Refer to “Publication Access” in Section 1-2.3.
vi IO-240 Series Engine Installation & Operation Manual
31 October 2011
TAB LE OF CON TE NT S
Chapter 1. Introduction
1-1. Scope and Purpose of This Manual ................................................................. 1-1
1-1.1. Effectivity Symbols...................................................................................................... 1-1
1-1.2. Advisories .................................................................................................................... 1-1
1-1.3. Using this Manual...................... ......................................................................... ......... 1-1
1-2. Publications...................................................................................................... 1-3
1-2.1. Service Documents ...................................................................................................... 1-3
1-2.2. Related Publications.................................................. ..................................... .............. 1-4
1-2.3. Publication Access....................................................................................................... 1-5
1-2.4. Publication Changes..................................................................................................... 1-5
1-2.4.1. Update/Change Distribution..............................................................................1-5
1-2.4.2. Suggestions and Corrections .............................................................................1-7
1-3. Contact Information......................................................................................... 1-8
Chapter 2. Engine Description
2-1. General Engine Description............................................................................. 2-1
2-1.1. Engine Model Number Definition ............................................................................... 2-2
2-1.2. Cylinder Number Designations.................................................................................... 2-2
2-2. Detailed Engine Description............................................................................ 2-3
2-2.1. Crankcase..................................................................................................................... 2-3
2-2.2. Engine Drive Train...................................................................................................... 2-4
2-2.2.1. Crankshaft..........................................................................................................2-4
2-2.2.2. Connecting Rods................................................................................................2-5
2-2.2.3. Camshaft...........................................................................................................2-6
2-2.3. Accessory Case........................................................................................................... 2-6
2-2.4. Cylinders...................................................................................................................... 2-7
2-2.4.1. Pistons................................................................................................................2-9
2-2.4.2. Hydraulic Valve Tappets...................................................................................2-9
2-2.5. Lubrication System.................................................................................................... 2-10
2-2.5.1. Oil Pump................................................................... ..................................... ..2-11
2-2.5.2. Oil Sump................................................................... ..................................... ..2-12
2-2.5.3. Oil Pressure Relief Valve ................................. .................................... ... ........2-12
2-2.5.4. Oil Cooler Adapter ................................................... ..................................... ..2-12
2-2.6. Ignition System .......................................................................................................... 2-14
2-2.7. Fuel System................................................................................................................ 2-16
2-2.7.1. Fuel Pump........................................................................................................2-16
2-2.7.2. Fuel Injectors...................................................................................................2-18
2-2.8. Starter Assembly........................................................................................................ 2-18
2-2.9. Alternator ................................................................................................................... 2-18
2-2.10. Engine Cooling ............ ......................................................................... ..................... 2-19
2-2.11. Induction System........................................................................................................ 2-20
2-3. Engine Specifications and Operating Limits ................................................. 2-21
2-3.1. Accessory Drive Ratios........................................................ ...................................... 2-25
2-3.2. Performance Data....................................................................................................... 2-25
IO-240 Series Engine Installation & Operation Manual vii
31 October 2011
2-3.2.1. IO-240-A Performance Charts ........................................................................2-26
2-3.2.2. IO-240-B Performance Charts.........................................................................2-28
Chapter 3.Engine Installation
3-1. Engine Installation........................................................................................... 3-1
3-1.1. Common Tools and Consumable Supplies Required .................................................. 3-1
3-1.2. Engine Receipt and Handling...................................................................................... 3-1
3-1.2.1. Uncrating the Engine.........................................................................................3-2
3-1.2.2. Crating an Engine for Shipping.........................................................................3-2
3-1.2.3. Acceptance Inspection....................................................................................... 3-2
3-1.3. Engine Transport.......................................................................................................... 3-2
3-2. Installation Procedures..................................................................................... 3-4
3-2.1. Prepare the Airframe for Engine Installation............................................................... 3-4
3-2.2. Prepare the Engine for Installation .............................................................................. 3-4
3-2.3. Installation Sequence................................................................................................... 3-5
3-2.3.1. Engine Pre-oiling............................................................................................... 3-7
3-2.3.2. Fuel Purge and Leak Check............................................................................... 3-8
3-2.4. Installation Inspection.................................................................................................. 3-9
3-2.5. Preflight and Run-up.................................................................................................... 3-9
3-3. Engine Installation Drawings ......................................................................... 3-11
3-3.1. IO-240-A Installation Drawings ................................................................................ 3-11
3-3.2. IO-240-B Installation Drawings ................................................................................ 3-15
3-3.3. IO-240 Common Installation Drawings .................................................................... 3-22
Chapter 4. Engine Operation
4-1. Introduction...................................................................................................... 4-1
4-2. Flight Prerequisites .......................................................................................... 4-1
4-2.1. Oil Change Interval........................................................................................... ........... 4-2
4-2.2. Engine Fuel Requirements........................................................................................... 4-2
4-2.3. Flight Check and Break-In........................................................................................... 4-2
4-2.3.1. Engine Break-In ................................................................................................4-3
4-2.3.2. Flight Check ......................................................................................................4-5
4-3. Normal Operation ............................................................................................ 4-7
4-3.1. Pre-operational Requirements...................................................................................... 4-7
4-3.2. Engine Start..................................................................... ..................................... ........ 4-8
4-3.2.1. Cold Start...........................................................................................................4-9
4-3.2.2. Flooded Engine................................................................................................4-10
4-3.2.3. Hot Start ............................................................................................. ............. 4-10
4-3.3. Ground Run-up .......................................................................................................... 4-10
4-3.4. Taxi Preparation.................................................................................. ....................... 4-12
4-3.5. Power Control............................................................................................................ 4-12
4-3.6. Take-Off..................................................................................................................... 4-13
4-3.7. Climb ......................................................................................................................... 4-14
4-3.8. Cruise......................................................................................................................... 4-15
4-3.9. Descent....................................................................................................................... 4-16
4-3.10. Landing ...................................................................................................................... 4-16
viii IO-240 Series Engine Installation & Operation Manual
31 October 2011
4-3.11. Engine Shutdown .................................. ..................................................................... 4-17
4-4. Emergency Operation .................................................................................... 4-18
4-4.1. Engine Fire During Start............................................................... ............................. 4-18
4-4.2. Engine Fire During Flight............................................................. ............................. 4-18
4-4.3. In-Flight Restart......................................................................................................... 4-19
4-4.4. Engine Roughness...................................................................................................... 4-19
4-4.5. High Cylinder Head Temperature..................................... ......................................... 4-19
4-4.6. High Oil Temperature ................................................................................................ 4-20
4-4.7. Low Oil Pressure........................................................................................................ 4-20
4-5. Engine Operation in Abnormal Environments .............................................. 4-21
4-5.1. Engine Operation in Extreme Cold................................................. ........................... 4-21
4-5.1.1. Engine Preheating................................. ..................................... ... ...................4-22
4-5.2. Engine Operation in Hot Weather............................................................ .................. 4-26
4-5.2.1. Cooling an Engine in Hot Weather..................................................................4-26
4-5.2.2. Engine Restart in Hot Weather........................................................................4-27
4-5.2.3. Ground Operation in Hot Weather ..................................................................4-27
4-5.2.4. Take-off and Initial Climb Out in Hot Weather ..............................................4-27
4-5.3. Ground Operation at High Density Altitude.............................................................. 4-28
4-6. Troubleshooting ............................................................................................. 4-28
Appendix A. Glossary
A-1. Acronyms........................................................................................................ A-1
A-2. Glossary.......................................................................................................... A-2
Appendix B.Torque Specifications
B-1. General Information......................................................................................... B-1
B-1.1. Torque Tips ................................................................................................................. B-1
B-2. Cylinder Torque Procedure.............................................................................. B-2
B-3. Torque Wrench and Extension Calculations.................................................... B-3
Appendix C.Standard Practices
C-1. Handling Parts.................................................................................................. C-1
C-2. Replacement Parts............................................................................................ C-2
C-2.1. Background................................................................................................................. C-2
C-2.2. Acceptable Replacement Parts.................................................................................... C-2
C-2.2.1. Know Your Supplier......................................................................................... C-3
C-2.3. 100% Parts Replacement Requirements..................................................................... C-3
C-2.4. Mandatory Overhaul Replacement Parts .................................................................... C-4
C-2.5. Authorized Oversize/Undersize Parts......................................................................... C-4
C-3. Torque.............................................................................................................. C-4
C-4. Safety Wiring Hardware .................................................................................. C-5
C-5. Tab Washer Installation.................................................................................... C-7
IO-240 Series Engine Installation & Operation Manual ix
31 October 2011
C-6. Helical Coil Insert Replacement...................................................................... C-8
C-6.1. Helical Coil Removal................................................................................................... C-9
C-6.2. Helical Coil Insertion................................................................................................. C-10
C-7. Stud Replacement.......................................................................................... C-11
C-7.1. Stud Removal............................................................................................................. C-11
C-7.1.1. Size-on-Size Rosan® Stud Removal...............................................................C-11
C-7.1.2. Step-Type Rosan® Stud Removal...................................................................C-12
C-7.2. Stud Installation......................................................................................................... C-13
C-7.2.1. Rosan® Stud Installation.................................................................................C-14
C-8. Cotter Pin Installation.................................................................................... C-15
C-9. Fuel System Service ...................................................................................... C-16
C-9.1. Fuel System Purge..................................................................................................... C-16
C-10. Gasket Maker® Application.......................................................................... C-17
C-11. Gasket Installation......................................................................................... C-18
C-12. Hose and Tubing Installation......................................................................... C-19
C-13. Harness Routing............................................................................................. C-20
LIST OF TABLES
Table 1-1. Related Publications .................................................................................... 1-4
Table 2-1. IO-240-A Specifications and Operating Limits .......................................... 2-21
Table 2-2. IO-240-B Specifications and Operating Limits .......................................... 2-23
Table 2-3. Accessory Drive Ratios .............................................................................. 2-25
Table 4-1. IO-240 Operating Limits .............................................................................. 4-4
Table B-1. General Torque Specification .......................................................................B-5
Table B-3. Hose Fitting (“B” Nut) Torque Specification ...............................................B-6
Table B-2. Tube Fitting Torque Specifications ..............................................................B-6
Table B-4. Component Specific Torque Specifications .................................................B-7
Table B-5. Specific Torque for Non-Lubricated Hardware ..........................................B-10
Table C-1. Rosan® Stud Primary & Secondary Bore Specifications ..........................C-12
x IO-240 Series Engine Installation & Operation Manual
31 October 2011
LIST OF ILLUSTRATIONS
Figure 1-1. Figure and Index Reference ................................................................... 1-2
Figure 1-2. Change Page Identification .................................................................... 1-6
Figure 1-3. List of Effective Pages ........................................................................... 1-7
Figure 2-1. Engine Model Definition .......................................................................2-2
Figure 2-2. Cylinder Number Designation ............................................................... 2-2
Figure 2-3. IO-240 Crankcase Features .................................................................... 2-3
Figure 2-4. Engine Drive Train ................................................................................ 2-4
Figure 2-5. Crankshaft .............................................................................................. 2-5
Figure 2-6. Connecting Rod ..................................................................................... 2-5
Figure 2-7. Camshaft ................................................................................................ 2-6
Figure 2-8. Accessory Case Features ....................................................................... 2-7
Figure 2-9. Cylinder Features ................................................................................... 2-8
Figure 2-10. Piston Features ....................................................................................... 2-9
Figure 2-11. IO-240-A Lubrication .........................................................................2-10
Figure 2-12. IO-240-B Lubrication ......................................................................... 2-11
Figure 2-13. Oil Pump ..............................................................................................2-12
Figure 2-14. IO-240-A Oil Cooler Adapter ............................................................. 2-13
Figure 2-15. IO-240-B Oil Cooler Adapter .............................................................2-13
Figure 2-16. IO-240-B Oil Cooler/Filter Adapter ................................................... 2-13
Figure 2-17. Continental Motors Magneto Part Number Structure .......................... 2-14
Figure 2-18. Continental Motors Ignition Distribution ............................................ 2-15
Figure 2-19. Slick Ignition Distribution ................................................................... 2-15
Figure 2-20. IO-240 Standard Fuel Injection System ............................................... 2-16
Figure 2-21. Standard Fuel Pump ............................................................................. 2-17
Figure 2-22. Altitude Compensating Fuel Pump ...................................................... 2-17
Figure 2-23. Fuel Injector ......................................................................................... 2-18
Figure 2-24. Engine Cooling .................................................................................... 2-19
Figure 2-25. IO-240-A Induction System ................................................................. 2-20
Figure 2-26. IO-240-B Crossflow Induction System ............................................... 2-20
Figure 2-27. IO-240-A Fuel Flow vs. Brake Horsepower ........................................ 2-26
Figure 2-28. IO-240-A Sea Level Performance ....................................................... 2-27
Figure 2-29. IO-240-B Fuel Flow vs. Brake Horsepower ........................................ 2-28
Figure 2-30. IO-240-B Sea Level Performance ........................................................ 2-29
Figure 3-1. IO-240-A Top View .............................................................................3-11
Figure 3-2. IO-240-A Left Side View ....................................................................3-12
Figure 3-3. IO-240-A Front View .......................................................................... 3-13
Figure 3-4. IO-240-A Rear View ........................................................................... 3-14
Figure 3-5. IO-240-B Top View ............................................................................. 3-15
Figure 3-6. IO-240-B Left Side View .................................................................... 3-16
Figure 3-7. IO-240-B Front View ...........................................................................3-17
Figure 3-8. IO-240-B Rear View ............................................................................ 3-18
Figure 3-9. IO-240-B w/optional Oil Cooler-Filter Adapter Top View ................. 3-19
Figure 3-10. IO-240-B w/optional Oil Cooler-Filter Adapter Left Side View ........ 3-20
Figure 3-11. IO-240-B w/optional Oil Cooler-Filter Adapter Rear View ................ 3-21
IO-240 Series Engine Installation & Operation Manual xi
31 October 2011
Figure 3-12. Propeller Flange ................................................................................... 3-22
Figure 3-13. Exhaust Flange Dimensions ................................................................ 3-23
Figure 3-14. Standard Fuel Pump Installation .......................................................... 3-23
Figure 3-15. Standard Fuel Pump Adjustments ....................................................... 3-24
Figure 3-16. IO-240-B Altitude Compensating Fuel Pump Adjustments ................ 3-24
Figure 3-17. Throttle Lever Installation ................................................................... 3-25
Figure 3-18. Oil Cooler Adapter Connections ......................................................... 3-25
Figure 3-19. Oil Cooler Adapter Connections ......................................................... 3-26
Figure 3-20. Oil Cooler-Filter Adapter Connections ............................................... 3-26
Figure 3-21. IO-240-A Air Intake Flange ................................................................ 3-27
Figure 3-22. Alternator Connections ........................................................................ 3-27
Figure 3-23. Engine Mounts ..................................................................................... 3-28
Figure 3-24. Continental Motors Magneto Ignition Schematic ............................... 3-29
Figure 3-25. Champion (Slick) Magneto Ignition Schematic .................................. 3-29
Figure 3-26. Airframe Ignition Switch Connections to Magneto ............................. 3-30
Figure B-1. Torque Wrench ......................................................................................B-3
Figure B-2. Drive extensions ....................................................................................B-3
Figure B-3. Extension increases applied torque ........................................................B-4
Figure B-4. Extension decreases applied torque .......................................................B-4
Figure C-1. Right-hand-thread safety wire installation .............................................C-5
Figure C-2. Safety wire Patterns for Right-Hand Threads ........................................C-6
Figure C-3. Tab Washer Installation .........................................................................C-7
Figure C-4. Helical Coil Extraction Tool ..................................................................C-9
Figure C-5. Installing a Helical Coil Insert .............................................................C-10
Figure C-6. Rosan® Stud Removal Tool ................................................................C-12
Figure C-7. Rosan® stud removal tool installed on stud ........................................C-12
Figure C-8. Stud Sizes ............................................................................................C-13
Figure C-9. Minimum Material Thickness for Helical Coil insertion ....................C-14
Figure C-10. Rosan® Stud Installation Dimensions .................................................C-14
Figure C-11. Cotter Pin Installation ..........................................................................C-15
Figure C-12. Installing Hoses and Fittings ...............................................................C-19
xii IO-240 Series Engine Installation & Operation Manual
31 October 2011
Chapter 1 . Introduction
AA
BB
1-1. Scope and Purpose of This Manual
This manual is part of the interface control document for IO-240-A and B engine models.
This manual provides airframe interface requirements, installation instructions and engine
operating instructions to supplement the Airplane Flight Manual (POH)/Pilot’s Operating
Handbook (POH).
Instructions in this manual are specific to the IO-240 Series engines. For information
specific to other Continental Motors engine series, accessories, or the airplane, refer to the
appropriate manual. Chapters are arranged in sequential order to install, test, and operate
the engine.
1-1.1. Effectivity Symbols
Va riations in IO-240 Series engine models require specific instructions or illustrations. If
peculiar information pertains to only a specific engine model in the series, an effectivity
symbol will accompany the information. Effectivity symbols found in this publication are:
IO-240-A IO-240-B
IO-240-B with altitude compensating fuel pump
Introduction
1-1.2. Advisories
This manual utilizes three types of advisories; defined as follows:
A warning emphasizes information which, if disregarded, could
result in severe injury to personnel or equipment failure.
CAUTION: Emphasizes certain information or instructions, which if
disregarded, may result in damage to the engine or accessories.
NOTE: Provides special interest information, which may facilitate
performance of a procedure or operation of equipment.
Warnings and cautions precede the steps to which they apply; notes are placed in the
manner which provides the greatest clarity. Warnings, cautions, and notes do not impose
undue restrictions. Failure to heed advisories will likely result in the undesirable or unsafe
conditions the advisory was intended to prevent. Advisories are inserted to ensure
maximum safety , ef ficiency, and performance. Abuse, misuse, or neglect of equipment can
cause eventual engine malfunction or failure.
1-1.3. Using this Manual
Except for engine installation drawings, illustrations in this manual are for reference only,
depicting the most prominent configuration in the engine series. Consult the parts catalogs
for engine model-specific illustrated parts breakdowns.
WARNING
This manual and the accessory manuals listed in Table 1-1 and certain service documents,
and other related publications constitute the Instructions for Continued Airworthiness
IO-240 Series Engine Installation & Operation Manual 1-1
31 October 2011
Introduction
(ICAs) prepared by Continental Motors and accepted by the Federal Aviation
Administration (FAA). This manual is prepared in a user -friendly format suited equally for
electronic viewing and print.
Exploded assembly illustrations accompany instructions throughout the manual. Parts in
illustrations (Figure 1-1.) are identified with numerical callouts (indexes). Corresponding
parts listings follow the illustrations for reference. The first time instructions refer to an
illustration, the figure number is identified in parentheses, followed by the callout. In
subsequent parts references, only the callout will be specified unless the referenced
illustration changes.
WARNING
Continental Motors ICAs are applicable only to Continental
Motors engines conforming to the approved, type certified
engine model configuration. Continental Motors ICAs must not
be used for aftermarket parts.
Figure 1-1. Figure and Index Reference
1-2 IO-240 Series Engine Installation & Operation Manual
31 October 2011
1-2. Publications
1-2.1. Service Documents
Continental Motors may issue Service Documents in one of six categories ranging from mandatory
(Category 1) to informational (Category 6). Definitions of the categories are listed below:
NOTE: Upon FAA approval, Continental Motors publishes service
documents for immediate availability on our web site. The service
document cover page indicates the engine models affected by the service
document. Service documents may alter or replace manufacturer’s ICAs.
Insert a copy of applicable Service Documents in affected manuals until
the service document instructions are incorporated in the manual, or the
service document is cancelled or superseded.
1Procedure
Category 1: Mandatory Service Bulletin (MSB)
Used to identify and correct a known or suspected safety hazard which has b een incorporated in whole or in
part into an Airworthiness Directive (AD) issued by the FAA or have been issued at the direction of the FAA
by the manufacturer requiring compliance with an already-issued AD (or an equivalent issued by another
country’s airworthiness authority). May contain updates to Instructions for Continued Airworthiness (ICAs)
to address a safety issue.
Category 2: Critical Service Bulletin (CSB)
This category identifies a condition that threatens continued safe operation of an aircraft, persons or property
on the ground unless some specific action (inspection, repair, replacement, etc.) is taken by the owner or
operator. Documents in this category are candidates for incorporation into an FAA Airworthiness Directive.
May contain updates to ICAs to address a safety issue.
Introduction
Category 3: Service Bulletin (SB)
Information which the product manufacturer believes may improve the i nherent safety of an aircraft or
aircraft component; this category includes the most recent updates to ICAs.
Category 4: Service Information Directive (SID)
The manufacturer directs the owner/operator/mechanic in the use of a product to enhance safety,
maintenance or economy. May contain updates to ICAs in the form of maintenance procedures or
specifications.
Category 5: Service Information Letter (SIL)
This category includes all information (not inclu ded in categories 1 through 4) that may be useful to the
owner/operator/technician. May contain updates to ICAs for optional component installations, which are not
covered in the Applicable Operator, Maintenance, or Overhaul Manuals.
Category 6: Special Service Instruction (SSI)
This category is used to address an issue limited to specific model and/or serial number engines. We will
distribute SSI notification directly to the affected engine’s owners.
service document set but will be made available through our Customer Service Department to owners of the
affected engines only . An SSI may update the applicable engine’s Instructions for Continued Airworthiness.
SSIs will not be included in the general
IO-240 Series Engine Installation & Operation Manual 1-3
31 October 2011
Introduction
1-2.2. Related Publications
The table below lists related publications, source, and accessibility relevant to IO-240
Series engine installation and operation.
WARNING
Use only the latest revision of all publications. Using superseded
information may jeopardize engine airworthiness
Table 1-1. Related Publications
Supplied
With
Publication
Engine
Maintenance and Overhaul Manual (M-6) Yes
S-20/S-200 Magneto Service Manual (X42002) Yes Yes Yes
Service Documents No Yes Yes
Parts Catalog No Yes (view only)No
Available
download at
web site
1
Yes
Printed
Manual
Available
for
Purchase
Yes
1. Our web site (http://continentalmotors.aero) provides 24-hour access to engine technical data via the Internet. If you are an internet service subscriber, you can access our web site to confirm and review the latest revision of this manual. If you have not subscribed to internet service and are using printed manuals, contact using the “Contact Information” on page 8. to confirm you have the latest revision of
the manual.
1-4 IO-240 Series Engine Installation & Operation Manual
31 October 2011
1-2.3. Publication Access
Contact an authorized Continental Motors distributor to discuss service subscription
options and pricing or visit the Continental Motors web site. Printed technical publications
may be ordered through authorized Continental Motors distributors or via the Internet at
http://continentalmotors.aero.
1-2.4. Publication Changes
The instructions in this manual represent the best and most complete information available
at the time of publication. Product or process improvements may trigger changes to
existing product design specifications or procedures contained in publications. As new
technical information becomes available, Continental Motors will make the information
available to the customer.
New information may be contained in Continental Motors
service documents. Service documents applicable to engines
and accessories within the scope of this manual must be
complied with as defined in these documents. This manual and
other related publications noted herein constitute the ICAs
prepared by Continental Motors and accepted by the FAA.
Introduction
WARNING
Continental Motors releases publication changes in the form of either change pages or
complete publication revisions, depending upon the extent of change. Service Documents
may supplement or replace technical information contained in one publication or an entire
series of publications. Such Service Documents represent a change to the published ICA
until the individual publications incorporate the latest technical information.
1-2.4.1. Update/Change Distribution
Document updates are available on our web site upon notification of FAA document
approval. Printed publication subscribers receive printed changes and revisions as they are
released.
Document revisions are released if the update changes more than 50% of the contents of a
publication. Revisions replace the previous version of a publication from cover to cover.
Minor corrections are released as change pages to the original publication, identified with
a change number and effective change date in the page footer. Information on the page that
changed from the previous edition is identified by a vertical, six-point black line (Figure
1-2.), referred to as a “change bar” in the outside margin of the page. A change page
replaces only the previous edition of the affected page.
IO-240 Series Engine Installation & Operation Manual 1-5
31 October 2011
Introduction
Change Bar
Change
Number
Change
Date
Change Bar
Change
Number
Change
Date
Change Bar
Change
Number
Change
Date
1-6 IO-240 Series Engine Installation & Operation Manual
Figure 1-2. Change Page Identification
Page A of the manual contains the original publication date and an itemized list of changes
issued for the technical manual (Figure 1-3.). If change pages are issued for the manual,
the change will be identified, with an effective date under the heading “Effective Changes
for This Manual.” The list of effective pages, itemizes the pages in each section, by
change number. Original pages are designated by a 0 in the List of Effective Pages
“Change” column.
31 October 2011
Introduction
Effective Manual
Changes and
Change Dates
Itemized List
of Effective
Pages
Effective Manual
Changes and
Change Dates
Itemized List
of Effective
Pages
Figure 1-3. List of Effective Pages
1-2.4.2. Suggestions and Corrections
Continental Motors solicits and encourages user comments regarding suggested changes
to this manual. Direct recommended changes or questions to the attention of
“Publications” at the address listed in Section 1-3, “Contact Information” or send
comments via email to CM.techpubs@continental.aero.
Notify our Customer Service Department immediately, using our toll-free number, if you
discover incorrect information which adversely affects safety.
IO-240 Series Engine Installation & Operation Manual 1-7
31 October 2011
Introduction
1-3. Contact Information
Continental Motors is available to answer technical questions and encourages suggestions
regarding products, parts, or service. If customers have an inquiry or require technical
assistance, they should contact their local Continental Motors distributor or field
representative. To contact a factory representative, refer to the contact information below:
Continental Motors, Inc.
P. O. Box 90
Mobile, AL 36601
Customer Service:
Toll free within the Continental United States: 1-888-826-5465
International: 1-251-438-8299
Internet: http://continentalmotors.aero.
1-8 IO-240 Series Engine Installation & Operation Manual
31 October 2011
Chapter 2 . Engine Description
2-1. General Engine Description
IO-240 engines are four-cylinder, four-stroke reciprocating aircraft engines. IO-240-A &
B engines are designed for fixed pitch, ground adjustable, or electric constant speed
propellers. There is no provision for a hydraulic propeller governor. Cylinder
displacement of 240 cubic inches is achieved with a 4.44 inch bore and a 3.88 inch stroke.
IO-240 series engines are equipped with continuous flow fuel injection and a either an
updraft or a downdraft induction system, depending on the engine model.
IO-240 series engines are designed with a wet sump, positive displacement oil pump
installed in the accessory case. When properly maintained, under normal operating
conditions, the desired oil pressure is maintained by a pressure relief valve located in the
accessory case. Engine cranking is accomplished by a geared starter mounted on the
accessory case.
A gear driven alternator is installed on the accessory case. The engine is equipped with
two gear-driven magnetos. The downdraft exhaust system is supplied by the airframe
manufacturer.
IO-240 series engines have a doweled, six bolt propeller flange.
Engine Description
IO-240 Series Engine Installation & Operation Manual 2-1
31 October 2011
Engine Description
I O-240-B1
Specification Number
Model Identifier
Cubic Inch Displacement
Horizontally Opposed Cylinders
Fuel Injected
B
Shipping Designation
I O-240-B1
Specification Number
Model Identifier
Cubic Inch Displacement
Horizontally Opposed Cylinders
Fuel Injected
B
Shipping Designation
4
2
3
1
4
2
3
1
2-1.1. Engine Model Number Definition
The description of each alphanumeric character in the engine model number is given
below for the example engine model number IO-240-B1B (Figure 2-1).
Figure 2-1. Engine Model Definition
2-1.2. Cylinder Number Designations
Refer to Figure 2-2:
• The front of the engine is the end closest to the propeller and the rear of the engine is
the accessory end.
• V iewed from the rear of the engine, the left-side cylinders are designated by even num-
bers 2-4, with Cylinder 2 being closest to the rear.
• The right side cylinders have odd number sequential designation 1-3, with Cylinder 1
being closest to the rear.
• Firing order of the engine is 1-3-2-4.
Figure 2-2. Cylinder Number Designation
2-2 IO-240 Series Engine Installation & Operation Manual
31 October 2011
2-2. Detailed Engine Description
REAR CRANKSHFT
BEARING BORE
Cyl #2 Cyl #4
2-4 OR L/H
CRANKCASE HALF
INTERMEDIATE
CRANKSHAFT BEARING BORE
BACKBONE
CRANKSHAFT NOSE
SEAL LAND
FRONT
CRANKSHAFT
BEARING BORE
CAMSHAFT
BEARING BORE
TAPPET
GUIDES
SPINE BELOW
CAMSHAFT
CAMSHAFT
BEARING BORE
OIL SUMP
MOUNT FLANGE
ACCESSORY CASE
MOUNT FLANGE
TAPPET
GUIDES
FUEL
PUMP
MOUNTING
PAD
REAR CRANKSHFT
BEARING BORE
Cyl #2 Cyl #4
REAR CRANKSHFT
BEARING BORE
Cyl #2 Cyl #4
2-4 OR L/H
CRANKCASE HALF
INTERMEDIATE
CRANKSHAFT BEARING BORE
BACKBONE
CRANKSHAFT NOSE
SEAL LAND
FRONT
CRANKSHAFT
BEARING BORE
CAMSHAFT
BEARING BORE
TAPPET
GUIDES
SPINE BELOW
CAMSHAFT
CAMSHAFT
BEARING BORE
OIL SUMP
MOUNT FLANGE
ACCESSORY CASE
MOUNT FLANGE
TAPPET
GUIDES
FUEL
PUMP
MOUNTING
PAD
2-2.1. Crankcase
Two aluminum alloy castings are joined along the vertical center plane to form the
crankcase. The individual castings (with studs and inserts) are referred to as the “left
crankcase” and “right crankcase.” The crankcase provides a tight enclosure, sufficiently
rigid to support the crankshaft, camshaft and bearings, with oil galleries for lubrication.
Bosses molded in the crankcase castings are line bored in the assembled crankcase halves
to form bearings for the camshaft and saddles for precision crankshaft main bearing
inserts. Guides are bored through lateral bosses for hydraulic tappets. There are six studs
and two through-bolts for attaching cylinder base flanges. The fuel pump mounting pad is
located on the left crankcase half, forward of Cylinder 4 (Figure 2-3).
Cylinder mounting pads on the left and right crankcase are offset to permit each crankpin
to transmit the rotational force to the piston through the connecting rod. The crankcase
interior is vented by a breather assembly comprised of a tube and baffle assembly with a
side extension for a hose attachment. The breather assembly is pressed into a boss on the
top side of the right crankcase half, forward of Cylinder 3.
Engine Description
Figure 2-3. IO-240 Crankcase Features
IO-240 Series Engine Installation & Operation Manual 2-3
31 October 2011
Engine Description
Starter
Alternator
Crankshaft
Camshaft
Fuel Pump &
Vacuum
Pump Driv e
Shaft
Camshaft
GearTachometer
Drive Shaft Oil Pump
Drive Gear
Oil Pump
Driven Gear
Starter
Alternator
Crankshaft
Camshaft
Fuel Pump &
Vacuum
Pump Driv e
Shaft
Camshaft
GearTachometer
Drive Shaft Oil Pump
Drive Gear
Oil Pump
Driven Gear
2-2.2. Engine Drive Train
The engine drive train (Figure 2-4) consists of the crankshaft, camshaft and drive gears.
The crankshaft has a propeller flange at one end to attach a propeller for thrust. The starter
gear meshes with the outer teeth of the rear crankshaft gear to turn the crankshaft until the
fuel mixture in the cylinder is ignited by the spark plugs. A drive gear at the rear end of the
crankshaft interfaces with a gear mounted on the rear end of the camshaft to synchronize
intake and exhaust valve movement and magneto rotation, as well as supply driving force
to the gear driven alternator. The oil pump driven gear, along with the optional tachometer
drive are gear driven by the inner row of teeth on the camshaft. The engine driven fuel
pump, and the optional vacuum pump drive are driven by a gear on the forward end of the
camshaft.
Figure 2-4. Engine Drive Train
2-2.2.1. Crankshaft
The crankshaft (Figure 2-5) is an aircraft quality steel forging with three machined, main
journals supported by precision-bearing inserts in each of the three bearing saddles
machined in the crankcase. Four machined rod journals provide attachment of the
connecting rod assemblies.
The crankshaft gear is indexed on the crankshaft by a dowel and secured by machined
bolts. A neoprene oil seal over the crankshaft flange is seated between the crankcase
castings in the front shaft exit area, and is sealed to the crankshaft by a helical spring
inside the seal's cavity.
2-4 IO-240 Series Engine Installation & Operation Manual
31 October 2011
Engine Description
CRANKSHAFT
FLANGE
FRONT MAIN
JOURNAL
ROD JOURNAL
ROD JOURNAL ROD JOURNAL
REAR MAIN
JOURNAL
MIDDLE MAIN
JOURNAL
OIL
PASSAGE
#1
#2
#3
#4
OIL
PASSAGE
CRANKSHAFT
FLANGE
FRONT MAIN
JOURNAL
ROD JOURNAL
ROD JOURNAL ROD JOURNAL
REAR MAIN
JOURNAL
MIDDLE MAIN
JOURNAL
OIL
PASSAGE
CRANKSHAFT
FLANGE
FRONT MAIN
JOURNAL
ROD JOURNAL
ROD JOURNAL ROD JOURNAL
REAR MAIN
JOURNAL
MIDDLE MAIN
JOURNAL
OIL
PASSAGE
#1
#2
#3
#4
OIL
PASSAGE
NOTE: Some older models use castellated nut with cotter pin
SPIRAL LOCK NUT
BRONZE BUSHING
CONNECTING ROD
CONNECTING ROD
CAP
ROD BOLT
SHELL
BEARING
The flange type crankshaft has a propeller mount flange forged on the front end with six
tapped bushings pressed into holes spaced equally around the flange. Six bolts, screwed
into the shaft flange bushings, clamp the propeller between a loose front flange and the
shaft flange.
Figure 2-5. Crankshaft
2-2.2.2. Connecting Rods
The connecting rods halves (Figure 2-6) are machined from a single forging of aircraft
quality steel and cut into two pieces, splitting the center of the larger opening of the
connecting rod assembly. The resulting pieces, called the rod and cap are fitted with a two
piece bearing and attach to the crankpin or rod journal with special bolts and nuts.
The portion of the rod between the rod and the crankpin and piston pin ends is called the
“I” beam. A split steel-backed bronze bushing is pressed into the piston pin end and
machined for a precision pin-to-bushing fit.
Figure 2-6. Connecting Rod
IO-240 Series Engine Installation & Operation Manual 2-5
31 October 2011
Engine Description
FRONT REAR
#4 EXH #3 EXH #2 EXH #1 EXH
#3 & 4
INTAKE
#1 & 2
INTAKE
M/J
C/L C/L C/L C/L C/L C/L
M/J M/J
C/L - CAM LOBE
M/J - MAIN JOURNAL
2-2.2.3. Camshaft
The camshaft forging is machined on three main journals, six cam lobes and the gear
mount flange at the rear of the camshaft (Figure 2-7). The lobes and journals are ground
and hardened. Camshaft main journals are supported in the crankcase by machined
bearing saddles. Hydraulic tappets move inward and outward in their bores, following the
eccentric shape of the cam lobes. Four unequally spaced bolts secure the gear to the
camshaft and ensure proper positioning, locating the gears' timing mark in relation to the
cam lobes. The camshaft gear has internal teeth to drive the alternator. A front-mounted
bevel gear drives the accessory drive bevel gear and fuel pump through a common shaft.
Figure 2-7. Camshaft
2-2.3. Accessory Case
The accessory case (Figure 2-8) aluminum alloy casting is attached to the rear of the
engine crankcase, aligned with crankcase dowels. The accessory case is secured to the
crankcase by crankcase studs and various attaching hardware. Accessory mount pads on
the rear surface are machined in one plane parallel to the machined parting flange which
surrounds the front side of the casting. Mounting pads for the magnetos, alternator cover,
starter, tachometer drive, oil filter adapter, oil pressure relief valve and an oil suction
screen boss are provided. The accessory case casting has two holes above and three studs
to attach the starter. A mounting pad is provided for a permanent oil screen housing. In
lieu of the oil screen housing, an oil filter adapter, with a screw-on type oil filter is also
available.
The oil pump housing is machined into the internal portion of the accessory case. A
machined, threaded boss is located on the lower right side of the accessory case for
installation of a non-adjustable oil pressure relief valve. Oil pump gear chambers are
machined in the interior of the accessory case. The oil pump drive gear shaft hole is
machined in-line with the camshaft and the driven gear shaft hole is directly above it.
A semicircular opening at the accessory case bottom is a machined threaded hole to
accommodate installation of the oil suction tube. Passages cast into the accessory case
allow oil to flow from the oil suction tube to the oil pump gears, pressure relief valve, and
main oil gallery. The tachometer drive shaft is the slotted end of the oil pump driven gear
shaft.
2-6 IO-240 Series Engine Installation & Operation Manual
31 October 2011
Engine Description
STARTER MO UNTING
PAD
MAGNETO MOUNTIN G
PAD
TACH DRIVE
MOUNTING
PAD
ALTERNATOR
MOUNTING
PAD
OIL SCREEN
HOUSING
MOUNTING
PAD
OIL PRESSURE
HOUSING
MAGNETO
MOUNTING
PAD
RELIEF VALVE
2-2.4. Cylinders
The IO-240 engine have four, horizontally-opposed, air cooled cylinders, two on the left
side and two on the right side of the engine. The cylinders, pistons and valve drive train
provide the momentum to sustain crankshaft movement. Aviation fuel and air are drawn
into a cylinder during the intake stroke, compressed by the piston during the compression
stroke and then ignited by a high intensity spark from each spark plug (two per cylinder).
As the mixture is ignited, the expanding gases force the piston to move inward toward the
crankshaft during the power stroke.
The head and barrel assembly (Figure 2-9) consists of externally finned aluminum alloy
head casting and a steel, nitrided cylinder barrel for wear resistance. Helical coil thread
inserts are installed in upper and lower spark plugs holes. A rotocoil assembly retains two
concentric springs surrounding the exhaust valve and is locked to the stem by tapered,
semi-circular keys which engage grooves around the valve stems. An outer retainer holds
two concentric springs which surround the intake valve and is locked to the stem by
tapered, semi-circular keys which engage grooves on the stem.
IO-240 Series engines use a cross flow cylinder head design. The intake ports are located
on top of the cylinder head while the exhaust ports are located below. There are separate
intake and exhaust valve rocker covers made from zinc-plated stamped sheet steel. This
cylinder design is used in conjunction with a Balanced Induction System mounted above
the engine.
Figure 2-8. Accessory Case Features
IO-240 Series Engine Installation & Operation Manual 2-7
31 October 2011
Engine Description
ROCKER SHAFT
ROCKER ARM
VALVE RETAIN ER
KEYS
ROTOCOIL
EXHAUST
VALVE GUIDE
OUTER SPRING
INNER SPRING
SPRING SEAT
INTAKE VALVE GUIDE
INTAKE VALVE
SEAT INSERT
INTAKE VALVE
CYLINDER BARREL
EXHAUST
VALVE
COOLING FINS
CYLINDER HEAD
CYLINDER BARREL
COOLING FINS
CYLINDER BASE
FLANGE
CYLINDER SKIRT
ROCKER COVER
RETAINER
EXHAUST
VALVE
SEAT
INSERT
THRUST WASHER
(ONE ON EACH SIDE
OF EACH ROCKER ARM)
Figure 2-9. Cylinder Features
2-8 IO-240 Series Engine Installation & Operation Manual
31 October 2011
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