# Lycoming Mandatory Service Bulletin 667: Revision A

- Rights: © Avco Corporation. Filed by the FAA in regulations.gov docket FAA-2026-13797; AD 2026-22-13 incorporates this document by reference. Not covered by OpenAirDocs’ CC0 dedication.
- Document: [Lycoming Mandatory Service Bulletin 667](https://openairdocs.org/service-documents/lycoming/sb-667.md)
- Title as filed: Lycoming Mandatory Service Bulletin 667A
- Pages: 6
- PDF: https://openairdocs.org/files/sha256/b5/8d/b58d94e6166ac36fd60c6914f15465d3555b9b1804ac525a032b89b906609a4f
- Page: https://openairdocs.org/service-documents/lycoming/sb-667/file/b58d94e6166a

## Text

Each page's text from the PDF; open the PDF at a page with #page=N.

### Page 1

ISSUED REVISED PAGE NO. REVISION 
MO DAY YEAR MO DAY YEAR 1 of 6 A 03 10 26 03 12 26 
 ©2026 Avco Corporation. All Rights Reserved. 
Lycoming Engines is a division of Avco Corporation. 
MANDATORY 
652 Oliver Street 
Williamsport, PA 17701 U.S.A. 
Telephone +1 (877) 839-7878 (U.S. and Canada) 
Telephone +1 (570) 327-7222 (International) 
Fax +1 (570) 327-7101 
Email Technicalsupport@lycoming.com 
www.lycoming.com 
 
DATE:    March 12, 2026,               Service Bulletin No. 667A 
                                              (Supersedes Service Bulletin No. 667)    
                
SUBJECT:                         Piston Pin Replacement. 
MODELS AFFECTED: All Lycoming Engines or Cylinder Kits using LW -13445 Pins, or Spare LW -
13445 Pins with an 8130-3 dated between January 7, 2021, and December 15, 
2025. 
TIME OF COMPLIANCE: Refer to Required Action. 
REASON FOR REVISON:    Corrected Date Range in models affected and paragraph one. 
NOTICE: Incomplete review of all the information in this document can cause errors. Read the entire 
Service Bulletin to make sure you have a complete understanding of the requirements. 
This Service Bulletin provides Instructions for Continued Airworthiness (ICA). 
Lycoming Engines has determined that thin-wall piston pins P/N LW-13445 installed in engines, sold as 
spares, or sold within cylinder kits listed in table 1, that have an 8130-3 date in block 13 between January 7, 
2021, and December 15, 2025, may contain undesirable manufacturing artifacts in the inside bore. 
 WARNING: YOU MUST COMPLETE THE “REQUIRED ACTION” IN THIS SERVICE 
BULLETIN TO ENSURE THAT YOUR PISTON PINS ARE IN 
COMPLIANCE.  PISTON PIN FAILURE CAN CAUSE AN 
UNCOMMANDED AND COMPLETE LOSS OF POWER. 
Table 1: 
LW-13445 05K21213-A 05K21215-A 05K21231 05K21117 
05K23037 05K23038 05K23040 05K29652  
 
Required Action: 
Do not install any LW-13445 piston pins with 8130-3 dates in block 13 between January 7, 2021, and 
December 15, 2025. Remove and quarantine unused LW-13445 piston pins within the affected range. 
Arrange for the return of unused piston pins through the Lycoming Distributor from which they were 
originally procured. Order replacement inventory as needed. 
 
 
 
 
 
 
SERVICE BULLETIN

### Page 2

ISSUED REVISED PAGE NO. REVISION 
SB667 MO DAY YEAR MO DAY YEAR  2 of 6 A 
03 10 26 03 12 26 
 
Engines with Serial numbers Listed in Table 2 or Spare Parts with an 8130-3 Date in block 13 
between January 7, 2021 & March 22, 2023: 
• At any maintenance event requiring the removing of a cylinder assembly with an affected LW-13445 
piston pin: 
o Replace with new piston pin in accordance with the appropriate Lycoming maintenance 
publication for your engine model. 
• At next overhaul, not to exceed the time listed in the current revision of Lycoming Service 
Instruction 1009: 
o Replace with a new piston pin in accordance with the current revision of Lycoming 
mandatory Service Bulletin 240. 
Engines with Serial Numbers listed in Table 3 or Spare Parts with an 8130-3 Date in Block 13 between 
March 23, 2023 & December 15, 2025: 
• In the next 25 hours of operation, not to exceed 150 hours’ time in service: 
o Replace with new piston pin in accordance with the appropriate Lycoming maintenance 
publication for your engine model. 
• If greater than 150 hours’ time in service: 
o Before next flight, complete “Oil Servicing, Metallic Solids Identification After Oil Servicing, 
and Associated Corrective Action” in accordance with the current revision of Lycoming 
Mandatory Service Bulletin 480. 
o If no recommended corrective action per Service Bulletin 480, w ithin 5 hours of operation, 
replace with new piston pin in accordance with the appropriate Lycoming maintenance 
publication for your engine model. 
NOTICE: Do not pull the cylinder completely past the piston since it could require additional work, parts 
replacement and break-in of engine.

### Page 3

ISSUED REVISED PAGE NO. REVISION 
SB667 MO DAY YEAR MO DAY YEAR  3 of 6 A 
03 10 26 03 12 26 
 
Warranty: 
This service document is mandatory. 
Consideration for compliance with this service document will be 12 months from the date of release of this 
service document. 
Affected engines within the factory warranty period may qualify for parts and labor coverage as required to 
comply with this service document as outlined in Lycoming Engine’s Limited Warranty available online 
at www.lycoming.com/Warranty. Contact an Authorized Lycoming Distributor for assistance in filing a 
warranty claim and to order all necessary parts. 
Affected engines not within the factory warranty period may qualify for parts and labor coverage as required 
to comply with this service document by filing a claim for: 
• Reimbursement of the replacement parts. 
• Associated Standard, Non-Expedited Freight. 
• Removal and Reinstallation Labor in accordance with the current applicable Lycoming Warranty 
Policy and latest revision of Lycoming’s SSP -875 Removal and Installation Labor Allowance 
Guidebook. 
Contact an Authorized Lycoming Distributor for assistance in filing a warranty claim and to order all 
necessary parts. 
Return the removed Piston Pins directly to Lycoming Engines at the address below: 
Lycoming Engines 
652 Olive Street 
Williamsport PA, 17701 
Attn: SB 667 Piston Pin Returns 
 
If you have any questions, contact Lycoming Technical Support by phone at +1 -570-327-7222 or                        
+1-877-839-7878 or email to Technicalsupport@lycoming.com.

### Page 4

ISSUED REVISED PAGE NO. REVISION 
SB667 MO DAY YEAR MO DAY YEAR  4 of 6 A 
03 10 26 03 12 26 
 
Table 2: 
O-235 Series 
L-10034-15 L-10775-15 L-13039-15 L-14932-15 L-15078-15 L-15105-15 
L-15118-15 L-15208-15 L-16155-15 L-17599-15 L-18529-15 L-18855-15 
L-18963-15 L-19897-15 L-20160-15 L-20275-15 L-20355-15 L-20787-15 
L-21612-15 L-21906-15 L-21951-15 L-22180-15 L-22647-15 L-22951-15 
L-23192-15 L-23952-15 L-24058-15 L-24837-15 L-25284-15 L-25386-15 
L-25477-15 L-25499-15 L-25508-15 L-25657-15 L-25695-15 L-25713-15 
L-25744-15 L-25958-15 L-26020-15 L-26021-15 L-26022-15 L-26023-15 
L-26024-15 L-26025-15 L-26026-15 L-26027-15 L-26028-15 L-26029-15 
L-26030-15 L-26031-15 L-3050-15 L-7085-15 L-9077-15 RL-10444-15 
RL-10862-15 RL-11088-15 RL-11119-15 RL-12019-15 RL-12814-15 RL-12868-15 
RL-13203-15 RL-13596-15 RL-13601-15 RL-13628-15 RL-13784-15 RL-13785-15 
RL-13788-15 RL-13884-15 RL-13905-15 RL-13906-15 RL-13953-15 RL-14053-15 
RL-14250-15 RL-14396-15 RL-14462-15 RL-14511-15 RL-14585-15 RL-14674-15 
RL-14680-15 RL-14765-15 RL-14837-15 RL-14895-15 RL-14898-15 RL-14920-15 
RL-14952-15 RL-14960-15 RL-15054-15 RL-15055-15 RL-15133-15 RL-15272-15 
RL-15382-15 RL-15502-15 RL-15570-15 RL-15758-15 RL-15847-15 RL-15958-15 
RL-15979-15 RL-16030-15 RL-16096-15 RL-16100-15 RL-16264-15 RL-16395-15 
RL-16564-15 RL-16706-15 RL-16733-15 RL-16736-15 RL-16750-15 RL-16762-15 
RL-16862-15 RL-16900-15 RL-16962-15 RL-16973-15 RL-17104-15 RL-17343-15 
RL-21928-15 RL-23265-15 RL-23671-15 RL-24002-15 RL-24050-15 RL-24145-15 
RL-24227-15 RL-25034-15 RL-25324-15 RL-25892-15 RL-9497-15  
O-540 Series 
L-1035-40E L-20379-40E L-28042-40E RL-6067-40E RL-9267-40E RL-9562-40E 
RL-10238-40E RL-12057-40E RL-13068-40E RL-13204-40E RL-13271-40E RL-15029-40E 
RL-15849-40E RL-17744-40E RL-18373-40E RL-18540-40E RL-19385-40E RL-19429-40E 
RL-19813-40E RL-20221-40E RL-20397-40E RL-20580-40E RL-23081-40E RL-23493-40E 
RL-23948-40E RL-24112-40E RL-24188-40E RL-24377-40E RL-26032-40E  
IO-540 Series 
L-11883-48E L-12752-48E L-15170-48E L-15214-48E L-24941-48E L-25598-48E 
L-26135-48E L-31136-48E L-31681-48E L-31877-48E L-32117-48E L-33795-48E 
L-33925-48E L-34240-48E L-34252-48E L-34351-48E L-34352-48E L-34358-48E 
L-34386-48E L-34412-48E L-35116-48E L-35201-48E L-37630-48E L-37635-48E 
L-37639-48E L-37652-48E L-37653-48E L-37657-48E L-37658-48E L-37660-48E 
L-37663-48E L-37666-48E L-37680-48E L-37681-48E L-37687-48E L-37694-48E 
L-37698-48E L-37700-48E L-37709-48E L-37710-48E L-37712-48E L-37718-48E 
L-37737-48E L-37738-48E L-37748-48E L-37756-48E L-37762-48E L-37763-48E 
L-37770-48E L-37786-48E L-37787-48E L-37812-48E L-37813-48E L-37817-48E 
L-37818-48E L-37836-48E L-37837-48E L-37838-48E L-37839-48E L-37840-48E 
L-37857-48E L-37862-48E L-37863-48E L-37868-48E L-37869-48E L-37878-48E 
L-37879-48E L-37880-48E L-37899-48E L-37900-48E L-37901-48E L-37910-48E

### Page 5

ISSUED REVISED PAGE NO. REVISION 
SB667 MO DAY YEAR MO DAY YEAR  5 of 6 A 
03 10 26 03 12 26 
 
Table 2 (Cont.):  
IO-540-Series 
L-37910-48E L-37911-48E L-37924-48E L-37925-48E L-37926-48E L-37927-48E 
L-37928-48E L-37946-48E L-37947-48E L-37948-48E L-37949-48E L-37950-48E 
L-37989-48E L-37990-48E L-37991-48E L-37992-48E L-37994-48E L-38015-48E 
L-38016-48E L-38017-48E L-38018-48E L-38034-48E L-38035-48E L-38036-48E 
L-38037-48E L-38038-48E L-38059-48E L-38060-48E L-38061-48E L-38062-48E 
L-38063-48E L-38078-48E L-38080-48E L-38085-48E L-38086-48E L-38097-48E 
L-38098-48E L-38099-48E L-38104-48E L-38105-48E L-38106-48E L-38118-48E 
L-38119-48E L-38120-48E L-38121-48E L-38122-48E L-38142-48E L-38143-48E 
L-38144-48E L-38145-48E L-38174-48E L-38175-48E L-38192-48E L-38193-48E 
L-38203-48E L-38206-48E L-38207-48E L-38225-48E L-38226-48E L-38227-48E 
L-38228-48E L-38241-48E L-38264-48E RL-3251-48E RL-3739-48E RL-4261-48E 
RL-4847-48E RL-5342-48E RL-6592-48E RL-8591-48E RL-9457-48E RL-9500-48E 
RL-11451-48E RL-10409-48E RL-11691-48E RL-13440-48E RL-14089-48E RL-15761-48E 
RL-16869-48E RL-17163-48E RL-17773-48E RL-18371-48E RL-18556-48E RL-18613-48E 
RL-19103-48E RL-20188-48E RL-20397-48E RL-20456-48E RL-20468-48E RL-20795-48E 
RL-22946-48E RL-23099-48E RL-23237-48E RL-24039-48E RL-24106-48E RL-24195-48E 
RL-24202-48E RL-24400-48E RL-24434-48E RL-24932-48E RL-25156-48E RL-25638-48E 
RL-25766-48E RL-25852-48E RL-26033-48E RL-26096-48E RL-26815-48E RL-27129-48E 
RL-27169-48E RL-27369-48E RL-27384-48E RL-27547-48E RL-28142-48E RL-28399-48E 
RL-28449-48E RL-28606-48E RL-29127-48E RL-29623-48E RL-30529-48E RL-30653-48E 
RL-30953-48E RL-31449-48E RL-32346-48E  
Table 3: 
O-235 Series 
L-7457-15 L-8310-15 L-9197-15 L-10092-15 L-10130-15 L-12500-15 
L-12846-15 L-12985-15 L-13029-15 L-13368-15 L-13533-15 L-13950-15 
L-14202-15 L-14475-15 L-14766-15 L-15489-15 L-16374-15 L-17109-15 
L-17370-15 L-17543-15 L-17796-15 L-18406-15 L-18959-15 L-19025-15 
L-19312-15 L-20493-15 L-22378-15 L-23167-15 L-23342-15 L-23627-15 
L-23884-15 L-24065-15 L-24178-15 L-24304-15 L-24535-15 L-25202-15 
L-25299-15 L-25423-15 L-25556-15 L-25600-15 L-25607-15 L-25615-15 
L-25671-15 L-25798-15 L-25873-15 L-25941-15 L-25954-15 L-25956-15 
L-25966-15 L-25997-15 L-26002-15 L-26032-15 L-26033-15 L-26034-15 
L-26035-15 L-26036-15 L-26037-15 L-26038-15 L-26039-15 L-26040-15 
L-26041-15 RL-11082-15 RL-11510-15 RL-13001-15 RL-13204-15 RL-14112-15 
RL-14422-15 RL-15327-15 RL-16223-15 RL-16292-15 RL-16338-15 RL-16610-15 
RL-17032-15 RL-17149-15 RL-17420-15 RL-17521-15 RL-17592-15 RL-17594-15 
RL-17663-15 RL-17700-15 RL-17846-15 RL-17925-15 RL-17969-15 RL-18341-15 
RL-18437-15 RL-18458-15 RL-18576-15 RL-18677-15 RL-18739-15 RL-18768-15 
RL-19202-15 RL-19428-15 RL-19889-15 RL-20153-15 RL-20154-15 RL-21514-15 
RL-22040-15 RL-22194-15 RL-22269-15 RL-22855-15 RL-23902-15 RL-24220-15 
RL-24756-15 RL-24770-15 RL-25095-15 RL-25211-15 RL-25385-15

### Page 6

ISSUED REVISED PAGE NO. REVISION 
SB667 MO DAY YEAR MO DAY YEAR  6 of 6 A 
03 10 26 03 12 26 
 
Table 3 (Cont.):  
O-540 Series 
L-21057-40E RL-11653-40E RL-12493-40E RL-12719-40E RL-20212-40E RL-20667-40E 
RL-24299-40E RL-25162-40E RL-25178-40E RL-25771-40E RL-25822-40E RL-25915-40E 
RL-26100-40E  
IO-540 Series 
L-13133-48E L-18936-48E L-20342-48E L-26943-48E L-28085-48E L-30949-48E 
L-33188-48E L-33382-48E L-33433-48E L-33873-48E L-34053-48E L-34198-48E 
L-34310-48E L-34311-48E L-34415-48E L-38287-48E L-38300-48E L-38301-48E 
L-38315-48E L-38325-48E L-38326-48E L-38352-48E L-38377-48E L-38380-48E 
L-38402-48E L-38437-48E L-38458-48E L-38461-48E L-38462-48E L-38468-48E 
L-38469-48E L-38497-48E L-38501-48E L-38505-48E L-38523-48E L-38524-48E 
L-38538-48E L-38539-48E L-38544-48E L-38545-48E L-38572-48E L-38574-48E 
L-38578-48E L-38583-48E L-38586-48E L-38607-48E L-38626-48E L-38627-48E 
L-38639-48E L-38640-48E L-38668-48E L-38669-48E L-38684-48E L-38685-48E 
L-38749-48E L-38750-48E L-38793-48E L-38794-48E L-38820-48E L-38854-48E 
L-38855-48E L-38858-48E L-38861-48E L-38862-48E L-38865-48E L-38866-48E 
L-38867-48E L-38868-48E L-38873-48E L-38878-48E L-38885-48E L-38886-48E 
L-38888-48E L-38889-48E L-38891-48E L-38892-48E L-38897-48E L-38900-48E 
L-38907-48E L-38908-48E L-38909-48E L-38922-48E L-38923-48E L-38931-48E 
L-38932-48E L-38938-48E L-38946-48E L-38947-48E L-38965-48E L-38966-48E 
L-38976-48E L-38981-48E L-38982-48E L-38997-48E L-38998-48E L-39000-48E 
L-39001-48E L-39008-48E L-39014-48E L-39015-48E L-39022-48E L-39035-48E 
L-39060-48E L-39061-48E L-39063-48E L-39070-48E L-39071-48E L-39100-48E 
L-39111-48E L-39112-48E L-39126-48E L-39134-48E L-39159-48E L-39160-48E 
L-39176-48E L-39177-48E L-39190-48E L-39193-48E L-39198-48E L-39199-48E 
L-39211-48E L-39212-48E L-39217-48E L-39218-48E L-39244-48E L-39245-48E 
L-39292-48E RL-2779-48E RL-9704-48E RL-12392-48E RL-15195-48E RL-15401-48E 
RL-15491-48E RL-15518-48E RL-15593-48E RL-15697-48E RL-19018-48E RL-19132-48E 
RL-19559-48E RL-21851-48E RL-21902-48E RL-22449-48E RL-24979-48E RL-26496-48E 
RL-26698-48E RL-26808-48E RL-26877-48E RL-26958-48E RL-27120-48E RL-27847-48E 
RL-27851-48E RL-28088-48E RL-28366-48E RL-28756-48E RL-29353-48E RL-30637-48E 
RL-32807-48E RL-33002-48E RL-33526-48E RL-34246-48E RL-35096-48E RL-35167-48E 
RL-35234-48E RL-35803-48E RL-35952-48E RL-36012-48E RL-36386-48E RL-36395-48E 
RL-36666-48E RL-36699-48E RL-37375-48E

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