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CONTINENTAL O-300 INFO Page Two...

MOTOR MOUNT AD AND CUTTING ALUMINUM...  (10199)
Subject: 125/145 Motor Mount AD (64-05-06)
From: Bob Runge <ejectr@javanet.com>
Jim,
Reading the above AD, it says to use "Lionoil" to flush the mounting tube. What is "lionoil? I found "Tube Seal(Line Oil)" in Aircraft Spruce which sounds like the stuff that one would want to use for the AD's purpose. Is it just a matter of dialect that "lion oil" sounds like "line oil" and "line oil is the stuff to use?

Bob:
I don't know if lionoil is commonly available any more. I think that "tube seal" would work just fine. Yes, line oil and lionoil are probably the same. Regardless, I would not hesitate to use it.

O-300 COMPRESSION  &  PROP QUESTIONS...  (10499)
From: Ed Lloyd <edlloydaustin@juno.com>
Monty,
In talking to Tony Otto last evening, he said you were an authority on Continental engines. That conversation sparked a question or so in my mind so here goes. The engine in my bird (3856K) has less than 200 hrs. since major. In reviewing the engine log a differential compression check was performed at 109.1 hrs. #1 74/80 #3 78/80 #5 74/80 #2 20/80 #472/80 #6 76/80. The #2 jug was removed, cylinder honed, new rings installed on that piston and reassembled. Checked OK on subsequent run and compression check. When I had the pre-buy inspection done at 192.7, a compression check was completed as follows: #1 77/80 #2 75/80 #3 78/80 #4 75/80 #5 72/80 #6 78/80.

Since I've owned the bird, I've put maybe a half dozen hours on it. Question is, should I do another compression check to see if #5 is holding it's own or continuing to decrease? Oil was changed following the pre-buy/annual and the screen checked normal. It had a few flecks of metal, however, Duane indicated that was normal. I'm seriously considering installing an Airwolf remote oil filter for better handling of the oil and ease of service. Additionally, there were no engine operating manuals, limits, etc., in the jacket file on the engine. The logs say I have a Sensenich 74 DC-0-60 prop installed now. On takeoff @ WOT, I'm turning about 2550, and the takeoff roll seems just a bit longer than I would like. It's coming unstuck at about 60 and I'm climbing @ 80 MPH. On leveling, and reducing RPM to cruise I'm showing about 9.5 GPH on the Swifttronics. That's giving me about 2350 to 2450 RPM at cruise. If I push over and get the bird "up on the step", I'm cruising at 135 to 140 MPH. Not being familiar with the Cont., are these figures in a normal range or should I do some adjusting? Do you know if Continental Motors would have any kind of Ops Booklet I could purchase from them? If so, what should I ask for. Hope I've given you enough background for you to evaluate. Thanks in advance, Ed Lloyd

Ed,
Don't worry about the compression reading. The O-300 series rarely seal up as tight as say, a 150 or 180 Lycoming. Readings of 80/60 and above are acceptable, what you don't want is any exhaust valve leakage. With 80 lbs. pressure in the cylinder, listen at the breather for air leakage (rings) at the air filter for leakage (intake valve) and at the exhaust for leakage (exhaust valve). If the reading is less than 60 on any cylinder, run the engine and warm it up, then recheck before doing anything drastic. The Airwolf filter may be a good idea, it might help lower the oil temperature a bit also. With a 60" pitch, you cannot expect too much initial acceleration, but that should be about right for overall performance and best cruise speed. 9.5 gph is a little too high at 2350 rpm. I lean whenever below 23" or 2400 rpm, at 23"x2400 I burn about 8 gph. TCM has an Operators Manual for Aircraft Engines - O-300 and "C" series form X-30015, which is very good, it is just a little booklet and only costs a couple of bucks. It has power charts and a lot of information not found any other place. -- Jim

COPY OF CONTINENTAL O-300 MANUAL AVAILABLE FROM JIM MONTAGUE...  (11199)
Jim Montague has copied the O-300 Ops Manual to an Adobe Acrobat document (".pdf" file) and has offered to share it with interested Swifters. Making this file downloadable off the GTS Homepage was discussed but the idea was rejected due to space concerns. The file is 678KB, takes about 5 minutes to download, and requires an Adobe Acrobat 3.0 reader to read the file. (If you don't have the Adobe reader it can be found and downloaded free from the FAA web sites.) Contact Jim Montague <monty747@aol.com>

CONVERTING FROM 125 TO 145...  (11199)
From: Larry LaForce <LaForce55@aol.com>
Subject: Re: 125 Cont.
Jim...
I was wondering what it takes to convert a 125hp Continental to a 145hp. Does it consist of only a stroke change with the same bore, or does the bore increase also? I am familiar with bores, strokes, rod lengths, pin locations, etc.etc. in the automotive racing world, but; I know nothing on the specifics on the 125hp Continental (bore, stroke, rod length, compression). Any info. would be greatly appreciated. Is there a manual available for this series engine? Thanks....Larry

Larry,
If the crankcase is a "heavy case" you need to change the crank, rods, pistons, cam and lifters. In other words, you might as well look for a complete O-300A, the later cylinders are better also. The earlier cylinders are legal, but the old "C" series cylinders are more prone to cracking than the newer ones. The bore is the same on all these engines. (4 1/16") All these engines use the same overhaul manual. "Overhaul Manual for Continental C-125, C -145 & O-300 series Aircraft Engines" -- Jim

MORE ON THE C125/145 DIFFERENCES ISSUE...  (11199)
Subject: Re: Engine
From: Larry LaForce <LaForce55@aol.com>
Jim...
Are there any visual differences between the C-125/C-145 and the O-300 engines? I assume that they use the same engine mounts. Thanks.... Larry

Larry,
The "heavy case" can be identified by 3 thru studs in the vicinity of the fuel pump. The "heavy case" has 3 - 7/16" nuts on the fuel pump side, the light case has none. There are several "heavy cases." The O-300 case is identified by smaller pipe plugs, 3/8" pipe, at the front end of the oil galleys. The earlier C-125 and C-145 cases have 1/2" pipe plugs. The "C" series cylinders have bronze inserts for the spark plugs, the O-300 cylinders have helicoils. The early oil sumps have only 3 bolts joining the accessory case, the later sumps have 5. The magnetos on the early engines are the Bendix SF-6-12. The later engines had Bendix S6LN-21 and the latest production O-300's had the Slick 664 mags. The earliest engines had 12 amp. generators, the latest had 60 amp. alternators. From the factory, the early engines had a gray case and black cylinders and the late engines were painted Continental gold. the C-125 (short stroke) and the C-145 and O-300A & B have a large crankshaft flange, SAE No. 3, with 8 - 3/8" nuts for the prop bolts. The O-300C and D have a smaller flange with 6 - 7/16 holes for prop bolts. There are other internal differences. The only problem with a C-125 is the early light case engines suffered crankcase cracks when used with a metal prop and turned up high rpm. A 125 with a heavy case is near "bullet proof" and will run 2700 rpm all day long as long as the early cylinders are not overtemped. The engine mounting is the same for all. -- Jim

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