SERVICE INSTRUCTION. 652 Oliver Street Williamsport, PA U.S.A. Tel Fax

Transcription

1 652 Oliver Street Williamsport, PA U.S.A. Tel Fax SERVICE INSTRUCTION DATE: March 6, 2012 Service Instruction No. 1458F (Supersedes Service Instruction No. 1458E and Service Instruction No. 1450) Engineering Aspects are FAA Approved SUBJECT: MODELS AFFECTED: TIME OF COMPLIANCE: Bolts (Identification and Installation) All Lycoming reciprocating aircraft engines Whenever new connecting rods and/or new connecting rod bolts are being installed Incomplete review of all the information in this document can cause errors. Read the entire Service Instruction to make sure you have a complete understanding of the requirements. This Service Instruction is written specifically for the Lycoming parts identified in Table 1. Table 1 identifies the recommended connecting rod assemblies and bolts currently available from Lycoming Engines. Connecting rod stretch and torque bolts are visibly similar. Refer to Table 1 to identify the correct service rod bolt for the connecting rod assembly. The part number is on the head of the bolt. Connecting rod assemblies come with the connecting rod bolt part number identified on the bolt head. For replacement connecting rod bolts, use Service Use Only part numbers. Refer to the applicable Parts Catalog for the correct bolt part number for each application. CAUTION LYCOMING DOES NOT GIVE APPROVAL FOR USE OF PMA PARTS ON ITS ENGINES. LYCOMING INSTALLATION INSTRUCTIONS DO NOT APPLY TO PMA PARTS. EQUIPMENT FAILURE COULD OCCUR IF LYCOMING INSTRUCTIONS ARE USED TO INSTALL PMA PARTS. 1 of 5 F 2012 Avco Corporation. All Rights Reserved. Lycoming Engines is a division of Avco Corporation.

2 TABLE 1 Lycoming Parts Current Assembly P/N Service Use Only * Bolt P/N Bolt Type Lycoming Use Only Bolt P/N LW S** Torque 14S23890 LW S ** Torque 14S S Stretch 14S23890 LW S LW Stretch 14S S Torque LW S Torque LW S LW Stretch 14S23889 LW S*** LW Torque 14S23889 : Connecting rods and connecting rod bolts must be replaced in complete assemblies. * "Service Use Only" bolts are to be used for field repairs. ** This connecting rod assembly can use connecting rod bolt P/N (stretch bolt) as an alternate to connecting rod bolt P/N (torque bolt). Either bolt must be used in pairs on the connecting rod assemblies in complete engine sets. *** This connecting rod assembly can use connecting rod bolt LW (stretch bolt) as an alternate to connecting rod bolt P/N LW (torque bolt). Either bolt must be used in pairs on the connecting rod assemblies in complete engine sets. Service Use Only Assembly No Longer Available at Lycoming Bolt P/N Bolt Type Torque LW S Torque LW Stretch LW Torque S Torque LW Torque S Torque LW Stretch LW Torque 2 of 5 F

3 CAUTION WHEN INSTALLING ANY CONNECTING ROD ASSEMBLY IN TABLE 1, THE SPECIFIED CONNECTING ROD BOLT FOR THAT PARTICULAR ASSEMBLY MUST BE USED. Bolt Installation Instructions Different connecting rod bolts have specific features identified in Table 2. Oversized connecting rod bolts also could be necessary if the connecting rod configuration is to be changed. Refer to the latest revision of Service Instruction No Service Use Only * Bolt P/N TABLE 2 Specific Bolt Features Type of Bolt Stretch Torque Torque 40 ft. lb (54 Nm) Torque Torque 40 ft. lb (54 Nm) LW Torque Torque 40 ft. lb (54 Nm) LW Stretch High tensile strength bolt Special Features Stretch length of bolt must be 2.255/2.256 in. ( / mm) measured using gage or equivalent All rod assemblies (connecting rod, bolts, and nuts) must be the same in a case where alternate rods could be approved for a particular engine. Make from LW for connecting rod LW Use with nut LW * "Service Use Only" bolts are to be used for field repairs. Underside of bolt head must install flush against the boss on the connecting rod Stretch length of bolt must be 2.255/2.256 in. ( / mm) measured using gage or equivalent ISSUED REVISED PAGE NO. REVSION 3 of 5 F

4 WARNING DO NOT ASSEMBLE STANDARD SIZE ROD BOLTS IN RODS THAT HAVE IN. (0.127 MM) OVERSIZE BOLT HOLES. REFER TO THE LATEST REVISION OF LYCOMING SERVICE INSTRUCTION NO ON ROD BOLT INFORMATION. CAUTION THE CONNECTING ROD BOLT CANNOT BE TIGHTENED CORRECTLY IF THE NUT ON THE CONNECTING ROD IS INSTALLED INCORRECTLY. THE FLAT FACE OF THE NUT MUST TOUCH THE CONNECTING ROD, AS SHOWN IN FIGURE 1. Anytime either the connecting rod bolt and/or nut are removed from a Lycoming engine, both must be replaced, regardless of apparent condition. 1. Make sure the connecting rod bolt and nut are clean, free of dirt and debris and that the threads are not damaged. 2. Apply Loctite Food Grade Anti Seize Lubricant, Loctite P/N , to the bottom two or three threads of the bolt only. Wipe away any excess with a clean, lint free cloth. 3. Refer to Table 1 to identify the type of connecting rod bolts to install: a. FOR TORQUE BOLTS: Tighten the torque bolts with a calibrated torque wrench. If a torque bolt cannot be installed at the specified torque value, send the bolt to Lycoming. See Reference 900, SSP 1776 Table of Limits, for the specified torque value. b. FOR STRETCH BOLTS: If 35 ft. lb. (47 Nm) of torque fails to give the minimum stretch of in. ( mm) length, apply additional torque until the bolt is at the correct stretched length. If 35 ft. lb. (47 Nm) causes an over stretched bolt (greater than in. ( mm) length) replace the bolt. Although variables in the joint can increase the torque for the specified stretch, a maximum torque of 55 ft. lb. (75 Nm) is acceptable for stretch bolts. Initial Torque: 35 ft. lb. (47 Nm) Maximum Torque: 55 ft. lb. (75 Nm) If the correct stretched length of 2.255/2.256 in. ( / mm) is not achieved within these torque values, discard and replace the bolt. 4 of 5 F

5 Figure 1. Nut, P/N LW ISSUED REVISED PAGE NO. REVSION 5 of 5 F