TCDS TC 108

MODELS: Avco Lycoming R-680-B4 series, R-680-4 and Military R-680-5, -7, -8, -11, -17 I.S. NUMBER: I.C. 108 Kodel - Lyccming R-680-4 and B4 K-680-846 Jype ORA Fating: kaximum continuous, np. xpm, at 5-1. press. alt. 225-2100-5-1. Jake-oti, ho, rEm, at full throttle 225-2100 Fuel (rinimum octane aviation gasoline) 65 bore and stroke, in. 4.625 × 4.5 Disflacement, cu. in. 680-4 Compression ratio 5.5:1 Leight (dry), ibe. 471 495 Fropeller shaft, SAE NO. Carturetion Stromkerg NA-RIA carburetor Stromberg NA-R7B carburetor with 2.0625 in. venturi with 2.0625 in. venturi ignition, dual Scintilla SC-A or SC-AZ magneto Scintilla DF or DFN magneto Ignition tiring, deg- BIC Front 30, Rear 30 Front 34, Fear 30 Certification basis Type Certificate No. 108 (See NOTE 4) NCIES 1. 2, 4 1.3.4 NOTE 1. Maximum permissitle cylinder head, tarrel, and oil inlet temperatures, 525 degrees F., 300 degrees F.. and 200 degrees F.. respectively. R-680-84 engines were formerly designated R-680-4. Serial Nos. 2-751 and 2-752 engines of these mcdels are eligible at 215 hp at 2000 rpm for all operations. The R-680-4 or k-680-B4 may be corverted to the R-680-B6 which makes it eligitle for use with a controllable pitch propeller. NOTE 3. Military model R-680-5 is identical to model R-680-B4B. Models K-689-84C, R-680-B4D and R-680-84L are similar to model R-680-B48, the differences being noted below. The corresponding military modeis are indicate: in farenthesis. Mcdel Difference F-680-B4C (R-680-7) Includes automatic valve gear lubrication. R-680-84D (R-680-8, -11) 490 lbs. (dry) weight includes automatic valve gear lubrication R-680-B4E (R-680-17) a it. tape, aceight inciudes automatic valve gear lubrication, AN type accessory drive, a redesigned crankshaft and steel link the pertinent die model designation and eNo. the pertinent certificated aircraft, its rame-plate should te revised to include NOTE #_ Approval expired 11/2/50. engines of these models manufactured after the dates showr. talow or with above those indicated, are eligible for use in certification aircraft: Model Serial No. Date R-680-4 and R-680-24 and R-680-B42 8-1619 3/18/39 R-680-E4C 2552 7/15/41 R-680-B4C 3935 12/31/41 R-680-B4E I015483 3/30/44