1、AS 840manual for theSAE 17.6 CUBIC INCHSPARK PLUG RATING ENGINEincluding maintenance and overhaulprepared under the auspices of theSAE Ignition Research Committeeby theSpark Plug Rating Engine Standardization Panelof theAircraft Piston Engine Ignition SubcommitteePublished July 1964by the SOCIETY OF
2、 AUTOMOTIVE ENGINEERS, INC.485 Lexington Avenue, New York, N.Y. 10017Printed in U.S.ATABLE OF CONTENTSSECTION PAGEI. Foreword 1II. Cylinder Assembly . 1III. Crankcase Assembly . 6A. 5000 Engine . 6B. 5750 Engine . 7IV. Induction System 7V. Ignition System. 7VI. Fuel System . 9VII. Cooling System 10V
3、III. Lubrication System11A. 5000 Engine .11B. 5750 Engine .11IX. Exhaust system.15X. Crankcase Breather System .15A. Standard System15B. Optional Crankcase VacuumSystem 15SECTION PAGEXI. Air Supply System 16XII. Maintenance and overhaul Procedure 18A. General 18B. Detailed Disassembly of5000 Engine
4、. 19C. Detailed Inspection and Assembly of 5000 Engine. 21D. Detailed Disassembly of 5750 Engine . 26E. Detailed Inspection and Assembly of 5750 Engine. 26XIII. Engine Break-In Schedule 28Appendix AManufacturing Tolerances and Replacement Limits 29Appendix B Bill of Materials - 5000 Engine . 33Appen
5、dix C Bill of Materials - 5750 Engine. 37Appendix D Abbreviations. 47All technical reports, including standards approved and practicesrecommended, are advisory only. Their use by anyone engagedin industry or trade is entirely voluntary. There is no agreement toadhere to any SAE Standard or SAE Recom
6、mended Practice,and no commitment to conform to or be guided by any technicalreport.In formulating and approving technical reports, the TechnicalBoard, its Councils and Committees will not investigate orconsider patents which may apply to the subject matter.Prospective users of the report are respon
7、sible for protectingthemselves against liability for infringement of patents.-SAE Technical Board Rules and Regulations1I. FOREWORDThis manual was prepared under the auspices of the SAE Ignition Research Committee by the Spark Plug Rating Engine Standardization Panel of the Aircraft Piston Engine Ig
8、nition Subcommittee. It defines the standard engine to be used in determining spark plug preignition ratings. The engine is known as the SAE 17.6 Cubic Inch Spark Plug Rating Engine. The background of its design, development, and applications is contained in SAE publication SP-243.In addition to des
9、cribing the engine, this manual deals with maintenance and overhaul instructions for the engine. Appendices providing engine manufacturing tolerances and replacement limits and engine bill of materials are also included. The manual does not, however, include the procedure for rating spark plugs; thi
10、s material is covered in the current SAE Handbook.The 17.6 engine has been used for many years in the spark plug industry to classify spark plugs by their preignition rating. Correlation of these ratings among the various test agencies has been accomplished with limited success primarily due to engi
11、ne variations. This correlation difficulty prompted the Aircraft Piston Engine Ignition Subcommittee of the SAE Ignition Research Committee to investigate the possibility of standardizing and improving this engine. The Ethyl Corp. (which originated and now owns the patterns for the 17.6 engine) cons
12、ented to the effecting of improvements in the engine, by SAE, with the provision that the Ethyl Corp. patterns not be changed.The Spark Plug Rating Engine Standardization Panel, which was established to standardize and improve the engine, consists of men who are closely associated with the use or ma
13、nufacture of the engine. The sum of their individual experience and the many special projects conducted by the panel have been gathered into this manual.Conformance with the engine description included in this manual and the diligent following of the Maintenance and Overhaul instructions, will resul
14、t in more uniform spark plug rating data from each engine and a closer rating correlation between engines.The manual will be revised periodically to reflect engine improvements which have been developed and thoroughly evaluated. Comments, advice, or recommendations concerning the manual, or the engi
15、ne it defines, will be welcomed by this committee and should be sent to SAE Headquarters for consideration. An engine of this type may be obtained from the Laboratory Equipment Corp., (Labeco), Mooresville, Ind., and all part numbers herein mentioned are those of Labeco, unless otherwise specificall
16、y stated. Two classifications of the 17.6 engine are described in this manual: the 5000 and 5750 engines. The 5000 engine (Fig. 1) is similar to the 5750 engine (Fig. 2), except that the latter is provided with the Lanchester balancing system, consisting of two counter-rotating, chain driven counter
17、-balance shafts, rotating at crankshaft speed, to dampen the unbalanced forces generated by the upper portion of the rod and piston assembly.II. CYLINDER ASSEMBLYThe cylinder assembly consists of a cast iron barrel assembly and a detachable cast iron cylinder head assembly; the latter including inte
18、gral rocker arm housings and covers completely enclosing the valve gear. The barrel assembly has a removable, centrifugally cast, iron cylinder sleeve mounted in the cylinder housing, and is attached to the head by ten 1/2 in. dia bolts which extend the length of the barrel. Coolant transfer from ba
19、rrel jacket to head is through ten holes drilled in the head and communicating with water passages between the cylinder sleeve and the jacket. The head is located on the upper end of the barrel by a pilot extension on the barrel. The combustion chamber is sealed by a copper asbestos ring gasket whic
20、h is compressed to a predetermined thickness when the ten bolts are tightened.The combustion chamber is hemispherical in shape with the axis of the two valves intersecting at the center of the sphere. The included angle between the valves is 72 deg. Valve seat inserts for both valves are expanded in
21、 the head. Two tapped holes, for spark plugs, are provided on opposite sides of the dome and in a plane at right angles to the plane through the valves. The included angle between the holes is 110 deg. Standard combinations of spark plug thread diameters and reaches are shown on Labeco Drawing No. 1
22、6100. (Note: The thermal plug used during spark plug rating is installed in one of the spark plug holes and contains a chromel -alumel thermocouple having a response rate of 7 1/2 sec for a change from ambient room temperature to 1150 50F when dipped in a molten tin bath at 1500 10F. The thermal plu
23、g temperature indicator has a 4.5 sec (max) travel time for the range of 0-1600 F.)The cylinder sleeve is of generally uniform thickness from2NOTE: Shown for illustrative purposes only. Detailed drawings may be obtained from Laboratory Equipment Corp., Mooresville, Indiana3NOTE: Shown for illustrati
24、ve purposes only. Detailed drawings may be obtained from Laboratory Equipment Corp., Mooresville, Indiana45Fig. 2B - The 5750 engine NOTE: Shown for illustrative purposes only. Detailed drawings may be obtained from Laboratory Equipment Corp., Mooresville, Indiana6top to bottom, except for a small o
25、uter flange near the lower end of the sleeve. This flange engages a steel ring flange which seals the sleeve to the cylinder housing and the head by gaskets and the same ten bolts which hold the barrel assembly to the head. The inner surface of the cylinder is knurled before finish honing and after
26、final honing the surface is Parco Lubrize treated.The coolant is brought in the lower end of the cylinder housing at the timing gear end and leaves the assembly at the top of the head between the rocker boxes. The cast steel rocker arms (providing a 5/16 in. valve lift for a 1/4 in. lift of the cams
27、haft) are equipped with needle bearings operating on floating case hardened solid steel rocker shafts, secured by cover plates bolted to the rocker box housings. Each rocker has a roller at the valve end and an adjusting screw at the push rod end. The valve gear is lubricated by pressure oil from th
28、e valve tappets, through a hole in the adjusting screw which affords splash lubrication, supplemented by additional exhaust valve lubrication effected by projecting the push rod housing 1/2 in. into the exhaust rocker box.The valves, one intake and one exhaust, have valve stem diameters and lengths
29、considerably greater than those generally provided for the valve head diameters used. Each valve is operated by two valve springs which provide satisfactory operation up to, and including 3200 rpm.III. CRANKCASE ASSEMBLYA. 5000 Engine - The gear end is considered the front end of the crankcase and t
30、he flywheel end, the rear of the crankcase. The crankcase consists of an extremely rigid iron casting with drilled oil passages allowing pressure lubrication to all bearing surfaces. Located by dowels and bolted to the front of the crankcase, a cast iron timing gear case cover encloses the timing ge
31、ars and oil pump. Bolted to the rear of the crankcase is a cast iron adapter which serves as the rear main bearing support. A shoulder on this adapter pilots in a hole in the rear supporting section to the crankcase deck assuring positive alignment. Bolted to this adapter and located by dowels and a
32、 shoulder is a small casting which serves as the outer race for the crankshaft rear oil seal rings. Two large covers bolted to the sides of the crankcase provide means for inspection of the crankcase interior.There are three main bearings: the front main bearing is pressed into the front supporting
33、section of the crankcase deck and the rear two main bearings are pressed into the removable adapter mentioned earlier; all three are locked in place by taper pins. All main bearings are of the one-piece, steel backed silver grid type and are precision bored in place; no adjustment is provided to com
34、pensate for wear. End play is adjustable by means of the crankshaft rear oil retainer nut which screws on the crankshaft with a left hand thread. The rear of this race is slotted and locked in position by the fly-wheel key. End thrust is absorbed by the shoulder on the rear crankshaft cheek, by the
35、crankshaft rear oil retainer nut, and by shoulders on the rear main bearings.The crankshaft is a very rigid steel forging, has hardened bearing journals to insure minimum wear, and is counter-weighted to balance one-half the reciprocating weights as well as all the centrifugal weight in accordance w
36、ith standard practice. Keyways are provided for flywheel, timing gear, timing disc spacer sleeve, and accessory drives. Threads are provided for the crankshaft front lock nut and the crankshaft rear oil retainer nut. The cast flywheel bears directly on a tapered and hardened section at the rear of t
37、he crankshaft and is held by key and lock nut. At those points where the crankshaft extends through the crankcase, piston ring type oil seals are used.The camshaft, driven through helical gears, is carburized steel with case hardened bearing journals and cams, the gear being held to the camshaft by
38、Woodruff key and lock nut. The front of the camshaft extends through the timing gear case for an auxiliary drive, leather or Victoprene oil seals being used at this point. There are two bronze camshaft bearings: the front bearing, which absorbs the camshaft end thrust, is bolted by a flange to the f
39、ront supporting section of the crankcase; the rear bearing is a bushing which is pressed into the rear crankcase supporting section. End play can be adjusted by removing metal from the inner face of the front bearing.The valve lifters are of the roller type. The guides are iron castings and are held
40、 to the top deck of the crankcase by capscrews, positive vertical alignment being assured by shoulders which fit in piloting holes drilled in the crankcase deck.The connecting rod is a steel forging which has a precision shell type split bearing, the cap being held by two bolts of7generous proportio
41、ns. The bearings are precision bored steel backed silver grid and no adjustment is possible for wear. The wrist pin bushing is a press fit in the rod and is a hard cast bronze.The piston pin is hardened carburized steel, is solid and employs a full diameter end having 1-9/32 in. spherical radii.The
42、piston is cast iron, has four compression rings and one oil control ring, all located above the piston pin boss and incorporates a sodium filled capsule in the head. This capsule, cooled by an oil spray from the small end of the connecting rod, is used to prevent localized overheating of the piston
43、by more uniformly dissipating the heat to the cylinder wall through the rings and skirt and to the oil. The capsule consists of a two-piece, copper brazed chamber which totally encloses the sodium and is shrunk into the outer casting. Pressure on the middle of the piston head is directly transmitted
44、 to the piston bosses by the inner member of the capsule. The compression ratio of the engine is 5.6:1.B. 5750 Engine - The crankcase of the 5750 engine from the cylinder mounting surface to the crankshaft main bearing is basically the same as that of the 5000 engine. The crankcase from the main bea
45、ring to the base is extended to house two counter-rotating, chain driven counterbalance shafts. The timing gear case cover is enlarged to enclose the timing gears, the chain drive for the counterbalance shafts, and the chain tension idler sprocket. An increased capacity oil pump is mounted on the ou
46、tside of the timing gear case cover and is driven through an Oldham coupling by the left hand counterbalance shaft.The crankcase has three main bearings, similar to the 5000 engine. However, the end play of the crankshaft is controlled by dimensional machining of the thrust faces of the two inner ma
47、in bearings, with the adapter secured in place on the crankcase with the proper gasket.The crankshaft is machined from the same forging as used for the 5000 engine. The only difference is that it is longer and the rear end is machined to use a radial lip seal instead of the ring seal. The front ring
48、 seal is also replaced with a radial lip seal, sealing against the timing disc spacersleeve.The lead weighted counterbalance shafts are mounted in the lower part of the case. Their unbalance weight dampens out the unbalanced forces generated by the upper portion of the rod and piston assembly.The sh
49、afts are mounted on bronze bushings pressed into the rear of the case and front bushings pressed into a piloted bearing adapter. They are driven in opposite directions at crankshaft speed by a triple chain drive. The tension of the chain is adjusted by an idler sprocket mounted on an eccentric bushing which may be locked in the position giving the desired tension. The timing gears, camshaft, valve lifters, connecting rod and piston assembly are the same for both engines.IV. INDUCTION SYSTEMThe induction system consists of an air receiver assembly and an intake pipe (see Fig. 3). The air r
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