|
The details of converting the
E-series engine to 225 hp |
|
1. The crankshafts must have the fifth order damper, found on some -8 and all -11 engines. This is assembly #537661. Most of the -8 engines with this assembly have a "5" stamped on the front face of the crank at the raised portion where the front seal rides. 2. Cylinders with casting #532452 or #537727 are acceptable. Some early O-470's used the 727 cylinders, as well as late E-series. 3. Pistons #534895 must be used for the conversion. The pistons can be identified visually as being longer than early ones with two radii cuts in the skirt on each side to permit clearance of the crankshaft. The early piston is flat on the bottom of the skirt. Unless you intend to chrome the cylinders, use #536938 rings. The camshaft is entirely different. If your engine has 1/4 mounting bolts for the cam gear, use cam #531201, which is the E-225 series cam with small holes. This can be ordered from Continental and did list for about $130. 4. The carburetor is also different. It should be Bendix #PS5C 391583-1. This can be identified by looking into the top. There are four orifices; whereas, the 205 carburetor has only one. This carburetor was also used on some early O-470's, as well as the E-225 (such as some early Cessna 310's). Many -8 and -11 engines really need only the cam and carburetor, since at major the late pistons and cylinders have been used. The real early -8 cases had smaller studs and can be converted with a kit that Continental offers, which includes the throughbolts. This is essentially it; there are some AD's, such as valves, which must be complied with no matter how you are majoring. Significant differences are better take-off, climb, cruise, and altitude. On the 35 models — A-35, B-35, C-35, and D-35 — there are limitations as to maximum rpm and maximum cruise rpm, due to a difference in engine mounting. On all later models, 2600 maximum rpm for takeoff is the only limit, the same as any E-225. Many times this conversion can be done for only about $200 more than a straight major. Earl Boutell, Jr., ABS #902 8719 Meadow Lane Leawood, KS 66206 Dear Harold: Per your cover letter pertinent to Mr. Earl Boutell's description of the conversion of the E-185 to the E-225 series engine, I am submitting a few comments. The E-225 series require a crankshaft with fifth and sixth order dampers. The E-185-8 or -11 engines built after October 23, 1953, from serial number 22183 were equipped with this crankshaft. It can be identified by a "5" stamped on the front face of the oil seal race flange, just behind the spline, and may be observed by removing the propeller and rear cone and shims. The crank may also be identified by a notch on the counterweight support blade which is designed to clear a pin on the fifth order counterweight. The part number for the E-225 crankshaft is 537561-A2. Many years ago we offered a conversion service whereby modified E-185 crankshafts were available on an exchange basis. However, the demand became so small in later years that it became economically unfeasible, and the service was dropped. We no longer modify customers' crankshafts at the factory either, and I cannot tell you who is equipped to do this in the field. Engines below serial number 5122D are not eligible for conversion, even if the crankshaft has been replaced with the 225 hp crank, due to many basic differences in the crankcase and other parts of the engine. Other required changes are part number 538342 carburetor, 534895 pistons, either 536878 or 531201 camshaft (depending on the size of gear-attach screw holes), 537145 oil check valve, and the proper cylinders. Cylinders #538348, #538610, or #539344 may be used provided the stud holes are of the proper size and the choke conforms to the limits outlined in Section XV, Table of Limits, E-Series Overhaul Manual, form X30016. Identification of the cylinder assembly should not be made using the casting number of the cylinder head. This is not a good criterion. It is of the utmost importance that anyone involved in a conversion to the E-225 engine conform to the overhaul manual, parts manual, and all service bulletins. The parts manuals are superseded by the service bulletins and many upgrading changes are described in them. The manufacturers of accessories will also supply directives pertinent to their products. Service bulletins or letters have been issued by vendors of propellers, fuel pumps, generators, etc. After conversion, a new serial number will be issued for the E-225. Details for obtaining a new name plate are found in Teledyne Continental Service Bulletins. R. Scheffner Regional Service Representative Teledyne Continental Motors Aircraft Products Division |