Lycoming SERVICE INSTRUCTION

1 Lycoming652 Oliver StreetWilliamsport, PA 17701 15, 1986 SERVICE INSTRUCTION No. 1029D(Supersedes SERVICE INSTRUCTION No. 1029C)Engineering Aspects areFAA ApprovedDATE:SUBJECT:MODELS AFFECTED:TIME OF COMPLIANCE:Tightening Procedures for Crankcase Thru-Studs and BoltsAll Avco Lycoming piston assembling cylinder(s) to Avco Lycoming aircraft engines incorporatebolts and long thru studs that extend through thecrankcase halves primarily for holding themtogether. The studs also secure the cylinders to theirmounting decks on the basic types of thru studs are used: anchoredand anchored-thru studs are threaded into one ofthe crankcase halves; the free-thru studs are not. In-stead, the free-thru studs extend through bothcrankcase halves. Because of their interference fit inthe main bearing webs, the free-thru studs alsoserve as dowels to align the crankcase insure uniform loading on the main bearings, itis necessary to tighten these studs and bolts in a se-quence beginning at the approximate center of theengine and progressing evenly to both front and rearof the engine as described in detail in the different procedures are shown.

2 The first pro-cedure, shown in PART I, is to be used when theengine has been completely disassembled, or whenall the cylinders have been removed; the second pro-cedure, shown in part II, is used when individualcylinders are replaced on an assembled engine. Theprocedure shown in PART II is simpler to under-take, because bearing loading is I: TIGHTENING PROCEDURE FORCRANKCASE THRU-STUDS. (Disassembledengines, or engines on which all cylinders have beenremoved.)NOTEB efore installing cylinder hold-down nuts,lubricate crankcase thru stud threads withany one of the following lubricants, or com-bination of 90% SAE 50W engine oil and 10% STP2. Parker Thread Lube3. SAE 30W engine oil4. 60% SAE 30W engine oil and 40% ParkerThread 1 of 91. Before the cylinders are assembled on thecrankcase, install torque plate P/N ST-222 over the1/2 inch thru-studs to simulate the thickness of thecylinder base flange; then install nuts on the freeends of 1/2 inch thru-studs and tighten each to 300in.

3 Lbs. (25 ft. lbs.) Use tightening sequences thatfollow Figures 1 through 0-235 Series crankcases, install spacersor flat washers over the 3/8 in. or 7/16in. thru-studs (since torque plate P/NST-222 does not apply) and torque to 300 (25 ft. lb.).2. Using same sequence as specified in paragraph1, retorque the 1/2 in. thru-studs to 600 in. lbs. tor-que (50 ft. lbs). On 0-235 model engines using7/16-inch thru studs, retorque to 420-in. lb. (35 ). Where 3/8-inch nuts are used, do not tightenmore than 300 in. lb. (25 ft. lb.).NOTES ervice INSTRUCTION No. 1029Da. Four Cylinder Engines, Wide Cylinder Flange(See Figure 1).SIDESL4TH TIGHTEN ON LEFT SIDE5TH TIGHTEN CRANKCASE FASTENINGSTHRU IN SEQUENCE SHOWNB efore tightening free-thru studs, makesure that they extend equally from bothsides of 1. Left Side of Crankcase3. Using sequences shown in figures 1 thru 11,tighten the 3/8-inch and 1/4-inch nuts at thecrankcase parting flange. Torque values are:3/8-inch nuts, 300 in.

4 Lb. (25 ft. lb.);1/4-inch nuts and capscrews, 96-108 in. lb.;1/4-inch shear nuts, 55-60 in. tightening sequence procedures follow-ing the illustrations are numerically keyedto the legends in the illustrations. As forthose crankcase fastenings not specificallycovered, use any sequence and tighten totorque values listed in paragraph 3, Part -Tighten both ends of free-thru studs simul-taneously at rear of No. 2 cylinder and atfront of No. 3 -Tighten thru studs at rear of No. -Tighten both ends of free-thru studs simul-taneously in front of No. 2 cylinder and atfront of No. 1 - Tighten 3/8-inch nuts at front main bear-ing (left side) to 300 in. lb. (25 ft. lb.).5th -Tighten crankcase fastenings 5 thru 9 insequence -Tighten 3/8-inch nut 10 at camshaft bear-ing location (left side) to 300 in. lb. (25 ).Page 2 of 91ST TIGHTEN ONLEFT SIDE3RD TIGHTEN ON 2 NDRIGHT SIDE LEF5TH TIGHTEN CRANKCASE FASTENINGS,THRU IN SEQUENCEF igure 2. Left Side of Crankcase1st - Tighten thru studs at rear of No.

5 - Tighten thru studs at rear of No. - Tighten thru studs at front of No. - Tighten 3/8 nuts at front main bearing(left side) to 300 in. lb. (25 ft. lb.).5th - Tighten crankcase fastenings 5 thru 9 insequence - Tighten 3/8-inch nut and bolt 10 at rearcamshaft bearing location (left side) to 300in. lb. (25 ft. lb.).c. Four Cylinder Engines, Wide Cylinder Flange-"76" Series (See Figure 3).NOTEOn 76 series engines, initially torque all 1/2-inch free-thru and anchored-thru studs to300 in. lb. (25 ft. lb.). Then apply a finaltorque of 600 (50 ft. lb.). Tighten3/8-inch nuts at front main bearings to (25 ft. lb.). SERVICE INSTRUCTION No. 1029Db. Four Cylinder Engines, Standard CylinderFlange (See Figure 2).3RD TIGHTEN RIGHT SIDETIGHTEN ON1ST TIGHTEN LEFT SIDE2ND TIGHTENLEFT SIDE6TH TIGHTENLEFT SIDE-4TH TIGHTEN ON LEFT SIDE5TH TIGHTEN CRANKCASE FASTENINGS,THRU IN SEQUENCEF igure 3. Left Side of Crankcase1st - Tighten thru studs at rear of No. - Tighten thru studs at rear of No.

6 - Tighten thru studs at front of No. - Tighten 3/8-inch nuts at front mainbearing (left side) to 300 in. lb. (25 ft. lb.).5th - Tighten crankcase fastenings 5 thru 10 insequence Six Cylinder Engines (0-540 Type), WideCylinder Flange (See Figure 4).4TH TIGHTEN BOTH SIDES AT SAME TIME3RD TIGHTEN BOTH SIDES AT SAME TIME1 ST TIGHTEN BOTH SIDES AT SAME TIME2ND TIGHTEN BOTH SIDESAT SAME TIME7TH TIGHTEN RIGHT SIDE6TH TIGHTEN CRANKCASEFASTENINGS THRUIN SEQUENCE INDICATEDF igure 4. Left Side of CrankcasePage 3 of 9e. Integral Accessory Drive Engines (TIO-541),Wide Cylinder Flange (See Figure 5).2ND5TH TIGHTEN BOTH SIDES AT SAME TIMETIGHTEN ON LEFT SIDE 1ST4TH TIGHTEN BOTH SIDES AT SAME TIMETIGHTEN BOTHSIDES AT 3 RDSAME TIME TIGHTEN ONRIGHT SIDE ONLY7th6TH TIGHTEN THESE FASTENINGSTIGHTEN ON IN THE SEQUENCE INDICATED -LEFT SIDE SEQUENCE OPTIONAL FOR ALLOTHER CRANKCASE -FASTENINGSS ervice INSTRUCTION No. 1029D1st - Tighten both ends of free-thru studs simul-taneously at rear of No.

7 4 cylinder and atfront of No. 5 - Tighten both ends of free-thru studs simul-taneously at rear of No. 6 cylinder and be-hind No. 5 - Tighten both ends of free-thru studs simul-taneously at rear of No. 2 cylinder and atfront of No. 3 - Tighten both ends of free-thru studs simul-taneously in front of No. 2 cylinder and atfront of No. 1 -Tighten 3/8-inch nuts at front main bear-ing (right side) to 300 in. lb. (25 ft. lb.).6th - Tighten crankcase fastenings 6 thru 12 insequence - Tighten 3/8-inch nut 13 at rear camshaftbearing location (right side) to 300 in. lb.(25 ft. lb.).2nd - Tighten both ends of free-thru studs simul-taneously at front of No. 3 cylinder andat rear of No. 2 - Tighten nuts on thru bolts at rear of No. - Tighten both ends of free-thru studs simul-taneously at front of No. 1 cylinder andin front of No. 2 - Tighten 1/2-inch bolt in front of No. 1 - Tighten 1/2-inch stud in front of No. 1 - Tighten 5/16-inch camshaft bearing nuts 7thru 10 to 125-170 in.

8 Lb. (10-14 ft. lb.).f. Integral Accessory Drive Engines(TIGO-541), Wide Cylinder Flange (See Figure 6).5TH TIGHTEN ON LEFT SIDE ONLY4TH TIGHTEN BOTH SIDES AT SAME TIME2ND TIGHTEN BOTH SIDES AT SAME TIME\ AT SAME TIME3RD TIGHTEN ONRIGHT SIDE ONLYI I7TH TIGHTEN 3/8 INNUT6TH TIGHTEN THRU STUDS, THRU .BOTH SIDES AT SAME TIMEIN SEQUENCE 8TH TIGHTEN THESE FASTENINGS IN THESEQUENCE INDICATED - SEQUENCE ISOPTIONAL FOR ALL OTHERSF igure 6. Left Side of Crankcase1st - Tighten both ends of free-thru studs simul-taneously at front of No. 5 cylinder and atrear of No. 4 - Tighten both ends of free-thru studs simul-taneously at front of No. 3 cylinder and atrear of No. 2 - Tighten 1/2-inch thru bolts at rear of No. 5. Left Side of Crankcase1st - Tighten both ends of free-thru studs simul-taneously at front of No. 5 cylinder andat rear of No. 4 4 of 94th - Tighten both ends of free-thru studs simul-taneously at front of No. 1 cylinder and infront of No. 2 - Tighten 1/2-inch thru stud in front of No.

9 - In sequence, tighten both ends simultan-eously of free-thru studs, 6 thru - Tighten 3/8-inch nut, 13, at front mainbearing to 300-in. lb. (25 ft. lb.).8th - Tighten 5/16-inch camshaft bearing nuts14 thru 17 to 125-170 in. lb. (10-14 ft. lb.).g. Six Cylinder Geared Engines (Wrap-AroundCrankcase), Standard Cylinder Flange (See Figure7).4TH TIGHTEN ON RIGHT SIDE3RD TIGHTEN RIGHT SIDE1ST TIGHTEN ON LEFT SIDE2ND TIGHTEN ONLEFT SIDEI5TH TIGHTEN CRANKCASE FASTENINGSTHRU IN THE SEQUENCE INDICATEDF igure 7. Left Side of Crankcase1st -Tighten thru studs at rear of No. 4 - Tighten thru studs at rear of No. 6 -Tighten thru studs at front of No. 3 - Tighten thru studs at front of No. 1 - Tighten 3/8-inch nuts 5 thru 12 in sequenceshown (left side) to 300 in. lb. (25 ft. lb.).h. Six Cylinder Geared Engines (Open BottomCrankcase), Standard Cylinder Flange (See Figure8). SERVICE INSTRUCTION No. 1029D4TH TIGHTEN ON RIGHT SIDE3RD TIGHTEN LEFT SIDE1 ST TIGHTEN ON LEFT SIDE2ND TIGHTENLEFT SIDE5TH TIGHTEN CRANKCASE FASTENINGSTHRU IN THE SEQUENCE INDICATEDF igure 8.

10 Left Side of Crankcase1st -Tighten thru studs at rear of No. 4 -Tighten thru studs at rear of No. 6 - Tighten thru studs at rear of No. 2 - Tighten thru studs at front of No. 1 -Tighten 3/8-inch nuts 5 thru 12 in sequenceshown (left side) to 300 in. lb. (25 ft. lb.).i. Six Cylinder Direct Drive Engines,0-435A/0-540 type, Standard Cylinder Flange (SeeFigure 9).4TH TIGHTEN ON RIGHT SIDE3RD TIGHTEN ON LEFT SIDE1ST TIGHTEN ON LEFT SIDE2ND TIGHTEN ONLEFT SIDE-7TH TIGHTENRIGHT SIDETIGHTEN RIGHT SIDE 6TH TIGHTEN CRANKCASEFASTENINGS THRUIN SEQUENCE INDICATEDF igure 9. Left Side of CrankcasePage 5 of 91st -Tighten thru studs at rear of No. 4 - Tighten thru studs at rear of No. 6 -Tighten thru studs at rear of No. 2 -Tighten thru studs at front of No. 1 Tighten 3/8-inch nuts at front main bearing(right side) to 300 in. lb. (25 ft. lb.).6th - Tighten crankcase fastenings 6 thru 12 insequence -Tighten 3/8-inch nut 13 at rear camshaftbearing location (right side) to 300 in.