MONTY THE ANSWER MAN ARCHIVE

CONTINENTAL O-300 INFO Page SIX...


VACUUM PUMP ON EARLY O-300... (JULY 03)
Subj: vacuum pumps on cont. 145
From: Ray Brown <flswiftfixer@aol.com>
Jim, this is ray brown, down here in sunny, soggy fla. My fellow eaa member has a early B model Maule with an 0300 cont. I believe it is a A model. this stock model Maule has a belt/pully driven vacuum pump on the front of the engine. The V belt rides in a pulley mounted just aft on the prop. The pump in mounted like an alt. on a lyc. Has anyone tried to get this legal on a Swift? Maule in Georgia has the paperwork on it. I'm sure it is an aftermarket conversion. your thoughts on this please. Ray Brown

Ray
I never tried it myself, but I was told it won't work in the Swift cowl. I wonder if it might work in a Corben cowl? I guess if I had one handy I would try it! -- Jim

C-125 STUFF... (JULY 03)
Subj: Manifold Pressure
From: Bob Price <BobPriceSwift@aol.com>
Jim: Thanks again for the engine manual... It mentions manifold pressure but I could not find any specs in the manual.... @ 2450 RPM I am getting 26 plus inches... @ 2550 it gets into the 30 inch range! I have the 125 hp at this time... Also..do you have a 145 ...300-A or B engine or do you have any leads where I could find one? Thanks Jim! Bob >>

Bob
The power charts are in the Operators Manual. The 125 performance chart is on Pg. 11. If you follow a line up 2450 rpm to where is crosses full throttle, you will see that is about 122 hp. 2550 at full throttle at sea level is 125 hp. That chart is somewhat confusing as far as rpm x mp is concerned. (wrong?) Better is the altitude chart on Pg. 16 which is for an O-300 but is close for a comparative readings. You may have to enlarge the chart to read it clearly. See where the rpm line intersects whatever manifold pressure you want to run then read the horsepower at the right. Unless you are located close to sea level you should not get close to a 30" MP reading. Locally, (932 MSL) we get 27" MP max. I don't have any engines for sale. Just read the ads! -- Jim

BOB FINDS AN ENGINE... (AUG 03)
Subj: 300-A
From: Bob Price <bobpriceswift@aol.com>
Jim:
I have located an 300-A 145 Cont. Will I need to purchase an STC for this installation or is there other paperwork that will be necessary? The 125 has an alternator conversion mounted to the rear of the engine near the mags. Will this bolt onto the 145 which still has a generator? You mentioned in earlier emails to have my prop repitched to 59:.... will this give me a better cruise or climb? Thanks Jim!......... Bob P

Bob
It well be necessary to buy STC SA1-326 from the Swift Museum Foundation. If you retain the alternator technically you should get a field approval for that. Is the alternator approved or just "on there"? The same alternator that fits a 125 fits a 145. Increasing pitch is like going up a gear on your car -- it should go faster at the same rpm. Decreasing pitch is like driving in 2nd gear, it should accelerate better and climb better but not go as fast. -- Jim

BOB WAS EXPECTING AN INCREASE... (AUG 03)
Subj: STC 300
From: Bob Price <BobPriceSwift@aol.com>
I just received the STC for the 300 engines... The STC indicates that there is no increase in the Max Take Off weight of 1710 Lbs. I was expecting an increase.. In your archives you mention the Swift can handle 1780 Max... How did you come by this? Thanks Jim... Bob Price

Bob,
There is a GW increase available from Merlyn Products to 1970 lb. for the big engine Swifts. They also have (had?) an increase to 1835 lb. for the 145 Swift. You would have to call Merlyn to see if that is available. STC SA1-326 does not include any GW increase and I'm sure I never indicated such. -- Jim

O-300 OIL LEAK... (SEPT 03)
Subj: Oil Leak
From: Bruce Hubbard <brucehubb@cox.net>
I have a Cessna 172 with an 0-300 engine it has 450 hours on the engine. I’ve have been plagued with oil leaks. I had the engine resealed and the engine is still using one quart per 30 min. When I bought the plane it had 100 hours on the engine, but had not been flown for two years. do you think a top overhaul would solve my problem.

Bruce
I usually try to answer questions only for the Swift guys, but this may help some of them too so... It depends. It depends on what the mechanic that did your engine used for sealant on the various pieces. However, you should be able to seal up the leaks. If it is leaking at the case halves, clean it up well, then mask about 1/8" each side of the split. Mix up some Pro-Seal or PR-1422 and brush it on the area of the crankcase split. If the cylinders are leaking at the upper end where the pushrod tubes exit the rocker box they can be reswaged. This requires removing the rocker covers, rocker arms and pushrods and using a special tool. If they are leaking at the other end replacing the rubber connectors require cylinder removal. If the sump gasket is leaking just tightening the 1/4" nuts that hold the sump on may help. If the rocker gaskets are leaking they sell some replacement gaskets called "Real" gaskets which are a bright orange color. TCM has published a Service Letter on recommended sealants. Having said all this, your engine is using way to much oil. How is the general health of the engine as far as compression etc? Have you tried running the engine with less than 8 qt. of oil in it? The O-300's are noted for throwing out the first quart of oil. If you are losing oil out the breather an oil separator such as STCed by M-20 Turbos may help. I doubt if leaks alone could account for 2 quarts an hour of oil usage. Perhaps your engine does need at least a top overhaul. -- Jim

MICK IS FEELING THE PRESSURE... (SEPT 03)
Subject: Re: mp
From: Mick Supina <masupina@mmm.com>
I need to have you give me an education on manifold pressures. I really don't understand it and would like to know more. Do you have anything written on the web site?

Mick
I don't think there is anything basic on the site. Remember manifold vacuum from cars? Atmospheric pressure at sea level is 14.7 lb/sq/in. Manifold pressure measured in inches of mercury which is double that. I.E. standard sea level is 29.92. Normally aspirated engines normally read atmospheric pressure, less the losses in the carburetor, at full throttle. Supercharged engines can read 40 -60 inches depending on engine design. Some racing engines have used up to 100". (until they blew up!) An O-300 at our airport (932 msl) will read about 26" at full throttle. As you throttle back, or climb to a higher altitude, the manifold pressure reads less. A normally aspirated engine (non-supercharged) has a critical altitude above which the manifold pressure goes down below a desired reading even at full throttle. (usually 6,000 - 8,000 feet) A Swift with a stock cowl holds higher manifold pressure at a higher altitude than most airplanes because the carburetor is located in the higher pressure air of the cooling plenum with the updraft cowl. Generally, 23" or 24" of manifold pressure is desired for cruise flight. A fixed pitch prop must be matched to the engine and airplane to give the desired readings. A 75% power reading for an O-300 is 24" x 2400 rpm. My prop turns 2550 rpm at 24" which is maybe 80% power. If I want to use less power I must throttle back, the throttle is the only means of reducing power and rpm with a fixed pitch prop. Most engines idle with the manifold pressure guage needle at the bottom of the scale, about 10". The later O-300's have a lot of overlap on the cam and idle at 16" due to induction losses due to the overlap. Any setting below 20" is usually less than 50% power and not commonly used. On a Continental, carburetor heat is usually required below 18" as these engines are prone to carburetor ice at reduced power settings. Horsepower is a cross section of rpm and manifold pressure. For example 24" MP x 2400 rpm = 108 hp or 75% for an O-300. However 21" MP x 2700 rpm also = 108 hp or 75% but you would need a different (lower pitched) prop to reach this figure. Don't feel bad about needing manifold pressure explained. I am working on my third prop STC and some FAA engineers don't understand it either! -- Jim

PROP BOLTS...(JAN 04)
From: Todd Wilmar
Do the 0-300D's have a 6 or 8 bolt flange? Thanks Todd

Todd
The O-300D has 6 bolts plus two pins that go in to the prop. (small flange) The C-145, O-300A & B have the big flange and 8 bolts. -- Jim

HAPPINESS IS AN O-300...(JAN 04)
Subj: Swift Engines
From: Todd Asche <wcrcoi@midstate.tds.net>
Jim, I have found a C125 engine and prop (over hauled 150 hours ago) for 1500.00. The best that I have come up with for a 0300D ( SO FAR) is to build one up for about 10,000.00 plus the cost of a new prop. I am sure tempted to buy the 125 for the money?????? For the cost difference would I be that much happier with the 0300?? Thanks, Todd

Todd
I don't know your finances but the O-300 is a much better engine than a C-125. When I got the Swift I have now in 1990, I first went "economy" and overhauled the 125. My friend, who is a CFI and I like to fly with weighs 300 lb. I was afraid to try and fly with him because the 125 just didn't have any guts. I finally bit the bullet and bought a 145. All 125s are not as gutless as the one I had and if you want to get flying before you spend a lot of money go ahead with the 125. For the long run, you probably would be happier with the O-300D. -- Jim

SLICK MAG ON C-125...(FEB 04)
Subj: mag conversion to Slick 6364 installation on the TCM C-125
From: Norm Clark <norm.clark3@verizon.net>
You guessed it. Our FSDO is balking at a field approval for this. He knows there has been a prior approval and wants us to find that approval so he doesn't have to sign his name to the 337. Can you point us in the right direction? Thanks. Norm Clark

Norm
I have gotten those Slicks approved on a 125 via field approval. I can send you a copy of the 337 if necessary. I think Slick may have added the 125 to their STC by now. Harry Fenton used to work for Slick and he had a 125 Swift -- but he quit there and has a new job. -- Jim

DOWN DRAFT COOLING STC FOR THE O-300... (FEB 04)
Subj: STC down draft cooling 0-300
From: Dorothy Golding <dotgoldswift@mail.ev1.net>
Jim;
Duane needs to know if there is an STC for down draft cooling for the 0-300 engine. Stay warm. Dorothy

Dorothy
Yes, the Alturair STC for the fiberglass cowl and downdraft baffles. (SA68SO) In addition there have been one-time approvals for home made cowls and also for the stock cowl with a baffle to get the air to the top side of the cylinders. -- Jim

SLICK MAGS ON A C-125... (FEB 04)
Subj: Slick mags on C125
From: Harry Fenton <gippsaero@charter.net>
Hi Jim,
I just read the last update and someone mentioned problems with getting the Slicks approved on a C125. I can help out with this problem as I have written a number of letter to support field approvals. I worked for Unison for nearly 20 years, and most FAA organizations will take my letter as supporting documentation. If anyone is having a problem with the FAA, just contact me at gippsaero@charter.net. The STC for the Slick 6364 mags was in the process of being updated to include the C125 before I left. One of the major delays is that we were going to use my ship for the conformity inspection, and I have been busy and the weather closed in for the winter. I'm in the process of obtaining my DAR for my new job with Gippsland Aeronautics, so I will probably be able to speed up helping Unison get this STC fixed this Spring. As a side note to mags, the smoothest running set that I have run on my C125 to date are the old SF6 Bendix "box" mags. Too bad they are so big and heavy as the engine runs noticeably smoother. One of the features of Slick mags is that the cam used on Slick mags is a "slapper" as opposed to a true cam (as used in Bendix mags) in which the points are in constant tension on a contoured surface. The Slick cam snaps the points open at the ignition point and drops away from the point spring which can cause the points to bounce. The slot in the end of the rotor shaft is critical to cam placement and if the slot is not centered in the shaft, then the timing of the cam to point opening varies slightly. As a result, the mag timing may vary slightly every 180 degrees which can yield slightly rough operation. One of the tricks that I would use to equalize this problem was to install the mag on a timing bench to find the "high lobe" of the cam. I would simply sand down the high lobe to equalize the lift on both sides. This can maybe be done on the engine, but with all of the gear train backlash, kind of hard to nail exactly. -- Harry

EVEN ENGINES HAVE "ISSUES"...(MAR 04)
From: Swift31B@aol.com
Subject: Re: O-300
The engine in Janet's Swift has "issues". I'm trying to figure out my alternatives; whether to overhaul her C145 or just replace it with an O-300. Do you know of anyone who might have an overhauled or good low time O-300? Perhaps someone who has done a big engine conversion. I'm not quite ready to put an ad on the website just yet but I am asking around. Any advice you have on the best way to go would be appreciated. Regards. Alan

Alan & Janet,
There are only detail differences between a C-145-2 and an O-300A. For all practical purposes they are identical engines. For the record the differences are:

1. The cylinders on the C-145 have bronze bushings for the spark plugs. The O-300's have heli-coils.
2. The pipe plugs at the forward end of the oil galleys are one size larger on the C-145
3. The C-145's have Bendix SF-6-12 or S6LN-21 magnetos. The O-300's have Bendix S6LN-21 or Slick Model 664 magnetos.
4. The later O-300's have a superior oil seal for the starter clutch.
5. The later O-300's have an alternator.
6. The C-145 has a splitter above the carburetor, in the oil sump, which is sheet steel, held in with two rivets. The O-300's have the splitter cast in integral.
7. The carburetor is a Marvel Shebler 10-3237 for a C-145 and a 10-4895 for an O-300. The numbers may be different but the carburetors are for all practical purposes, identical.
8. The camshafts are all p/n 530803 but the later ones have suffix such as -AN, -AT or -AU. These camshafts seem to perform well at higher rpm, the earlier camshafts might perform better in climb. There were some cast iron camshafts before 1950 but I doubt any of these are around anymore. The C-125 used a cast iron camshaft. It is important not to use a cast lifter on a cast camshaft, they require a steel lifter. Also, a steel camshaft (p/n 530803) requires a cast lifter body. (p/n 530851)
9. The C-145 lifter bodies don't have a circlip to hold the "guts" in the lifter, the O-300's do. This has caused all sorts of grief to guys that pull a cylinder and break a lifter, necessitating splitting the case to replace the lifter.
10. The C-145's have "wet studs" -- the cylinder studs are installed in tapped holes that go into the case and thus possibly leak oil. The O-300 castings are revised so the studs are in blind holes and can't possibly leak. (I have seen O-300's made before 1960 with the C-145 style case)
11. All C-145 and O-300 engines with a "D" in the serial number have a dampened crankshaft. Continental made a few C-145's in 1948 with undampened crankshafts, I doubt if any of these are still around.

Thats all I can think of right off, if I think of something else I will let you know! -- Jim

SMALL CONTINENTAL ENGINE INFO...(MAR 04)
From: "Harry Fenton" <hlfenton@charter.net>
FYI, I have an archive of engine material for the small four cylinder Continentals that is also useful for the C125/C145/0300 series that you find interesting. Most of the information there is pretty good, but sometimes kind of rough in that it is kind of stream of thought answers (not unlike the stuff that has been archived from Jim's comments). I will eventually have a dedicated website for the four and six cylinder Continentals, time permitting. You can find my archived engine page at: http://www.bowersflybaby.com/tech/engines.htm
Anyway, feel free to contact me any time and maybe we'll meet at one of the fly-ins.
Best regards,
Harry Fenton
Gippsland Aeronautics
www.gippsaero.com

CAN YOU SAY "BOAT ANCHOR"???(APRIL 04)
Subj: C-125-2 available
From: Dave Stevens <DaveST@RP-L.com>
Jim,
I have a C-125-2 continental that originally was installed in a Swift. It is now flying in front of an EAA biplane. All logs go back to the test flights in 1948. It has about 2000 hrs total, 520 smoh. Do you think there is any demand for the original engine? Just wanted to know if many owners rebuild their Swift as stock, or if they all go for the bigger engines. Thanks!

Dave: The original 125 engines do not have much value -- that is why they are often seen in homebuilts. The Swift is about the only airplane to ever use the C-125! The C-145 and O-300A are externally identical so they make a "bolt in" replacement and are a much better engine. Back when used cylinders were valuable I used to sell the 6 cylinders from a 125 and junk the rest. New cylinders are now readily available so now the cylinders are not worth much. I wouldn't count on getting much more than $1000 for a good 125. If it has a "heavy case", a little more. -- Jim

CRANKSHAFT MODS...(APRIL 04)
From: BEWILLS@aol.com
The N number on my swift from the factory was NC78058, then changed to N78058 and finally changed to N599Z. The model number is GC-1B and serial number is 2058. It has the Cont. C145-2H motor and several mods including the stick mod. I am curious why the crankshaft was changed for a "A" model 300? I am guessing that it may have something to do with using an approved prop. Do you know if a vaccum pump can be mounted on the C145?

Terry
Changing the crankshaft to the "A" type permits the use of the 8 bolt props. (Sensenich 74DR and McCauley DM) That is no longer necessary because the revised STC SA1-326 permits the use of the Sensenich DC prop. My STC SA1490CH permits the replacing of the "D" crankshaft with the "A" type. A vacuum pump cannot be mounted on a C-145 in a Swift cowl. There is an STC for some airplanes to use a belt driven vacuum pump. The C-145-2H and the O-300A crankshaft take the same 8 bolt prop. The difference is the C-145-2H and O-300B have a different front main bearing and a hollow crankshaft with for provisions for a controllable prop. If a fixed pitch prop is installed on a C-145-2H or O-300B an aluminum plug with an "O" ring, held in with a snap ring, plugs the end of the crankshaft. -- Jim

PAT IS HEADED FOR AN ENGINE TEARDOWN...(AUG 04)
Subj: Engine problems
From: Pat Waters <GPWATERS@aol.com>
I am writing to get some advise as to perhaps what is going on inside that big noisy power plant up front. Perhaps you could give me some direction or pass this on to another for their thoughts. I recently had my O-300 overhauled in AL and upon its return and instillation, I began the break-in, etc., as written in the manual and instructed by the mechanic. The first thing I noted is that all I could get on take off was 2100 RPMs with a redline of 2600 RPMs. I flew it far about 25 hours on mineral oil and then at the change had a filter added and off I went. At 32 hours TT on the engine, the oil was changed (annual) and the filter opened. In it was found some very fine gold looking metallic substances. The engine was flushed and refilled with mineral oil only to find after another hour of over the field, there was again gold colored (either brass or bronze) metallic materials found. I the last flight, I again noticed only 2100 RPM at take off and also noted that at about 3000 ft when I applied full power and tried to climb no greater than 700 ft per minute, the engine slowed down to about 2000 RPM and I could feel a strong shaking of the aircraft as if I were almost lugging the engine. Obviously, I have now grounded my Swift but am looking for answers if others have had this experience. The CT stayed at 90C and the oil pressure stayed at 30 to 35 psi. The plane is not a performer I know, but it seems that it is lacking the spunk of a good engine. Am I doing something wrong or just not used to that type of performance. I would be afraid to carry a passenger at this time (excluding the oil problem) as it just does not fell 'up to the job.' Thank you and your staff for your considerations and thoughts. Best, GP Waters

Pat,
If there is metal in the oil at 32 hours, it sounds like the engine should be torn down for inspection. Right off the top of my head the thrust washers are the most likely culprit. They are brass. With the spark plugs removed, does the engine turn freely? You mention CT of 90 C -- don't you mean oil temp? Do you have a cylinder head temp gauge? If it were not for the fact that you mentioned the metal in the oil, I would have you check the compression, timing and prop but I think the metal in the oil is the main thing. -- Jim

PAT IS HEADED FOR AN ENGINE TEARDOWN PART DEUX... (AUG 04)
Subj: Engine problems
From: Pat Waters <GPWATERS@aol.com>
In the course of all this, a question has arisen in that I have an O-300B engine. There is an STC on this I suppose but how do I find it or is it your SA1490CH. I am not too sure but I am wondering if the removed engine sent for repair was the same returned, but anyway, I now have an O-300B and am told the carburetor is not correct which is why I have had so little power. As to the carburetor, it is 10-2848. Does that make sense?

Pat,
The original STC SA1-326 has been revised so the O-300B is legal. My STC SA1490CH is for the Sensenich 74DR-1 prop. There are several p/n's which are Ok. The 10-2848 is a C-125 carburetor. It is not the approved carburetor for a C-145 or O-300. The approved carburetor is a 10-3237 or 10-4895. Actually that is not your problem because a 125 carburetor will work on the O-300 and the old version of the STC to install the O-300 in a Swift called for using the 125 carb! I believe they will accept a 10-2848 carburetor as a core on a new or remanufactured 10-4895 carburetor, they should, all the major parts are the same! I was thinking some more about your problem, the only bronze parts in the engine are the thrust washers, the rocker bushings, valve guides and small end connecting rod bushings. (not brass as I said earlier) I really hate to say it, but I'm afraid tearing the engine down is the best option. -- Jim

STEVE ROTH RESPONDS TO PAT’S ENGINE WOES... (AUG 04)
From: Swift97B@aol.com
Subject: Pat Waters Engine Problems
When I installed new Millenium cylinders several years ago in my O-300, I had all of the rocker arms rebushed. I did no other changes to my engine. The first several oil changes showed lots of "gold" flecks in the oil. I flushed out the crank case each time and did normal oil/filter changes. It eventually cleared up. In my case, I believe the "gold" came from the rebushed rocker arms wearing in. The above would surely not result in the power loss you have. Regards, Steve Roth

NOT SO GOOD VIBRATIONS...(AUG 04)
Subj: A new vibration
From: Pat Waters <gpwaters@aol.com>
I feel like a pest, but am still in search of some answers. I am the fellow with the bronze/brass metallic residue in my O-300B engine which has 32 SMOH. In the course of discovery, it was noted that there was the 125hp carburetor on it and we have changed it to the 145 size (as per your thoughts). Now, when I run the engine up, at about 1200-1300 RPM there is a 'chatter' like vibration. It smoothes out above that but we feel it is unsafe. Have you or any of your associates experienced this. Could it be a broken engine mount? Could it be from within the engine? Could it be...? I'd appreciate some thought on the matter before we go any further. Thank you. GP Waters

Pat
A worse case scenario would be if a counterweight came off the crankshaft. The O-300 has two floating counterweights near the aft end. They are retained by pins which are locked in with snap rings. If a snap ring comes out, the counterweight can come off. It has happened more than once. At 1200 -1300 rpm the engine will be very rough. The way to find this is with the sump removed or one of the two rear cylinders removed. You might check for a broken valve spring or rocker arm first by removing the valve covers. -- Jim