Arceenut

I am trying to run an engine without creating an oily mess on my airplane. The method that I am trying is to provide lubrication to the bearings and piston without the excess amounts of oil mixed in the fuel. So far, indications are that my method is feasible. What have I done is fabricated a method to dry sump oil into the crankcase and running the engine on fuel only (NO OIL). I am using gasoline with full power on the glow plug. Maybe later I will mix some methanol with the gasoline to see if I can keep the glo plug lit without power as per the gasseres thread elsewhere in the forum. So far testing has proven that the system works. I have run about a quart of "regular out of the gas pump gasoline" thru an old Saito 45 4S at wot. Teardown and inspection shows no indications of damage or excess wear. There is NO oil out of the exhaust as proven by a Q-tip probe of the exhaust pipe. Further refinement and testing will have to be done before I will attempt to put a modified engine in a plane. Any comments or suggestions would be helpful and welcome.

av8tor1977

My Feedback: (6)

I think it is a cool idea. Keep at it, and please keep us informed.

AV8TOR

captinjohn

Is this a type of oil injection or oil reciculation? Just kinda wondering how the system works. Thanks Capt,n

Arceenut

I guess it is a recirculation system rather than an injection system. My terminology was off. Will post a diagram andphotos when I get time.

Arceenut

Here are some photos and a description of how it works.

The check valve in the oil return line creates a negative pressure in the crankcase when the piston rises. This will draw oil into the crankcase thru the small metering hole from the oil supply. Excess oil in the crankcase will be expelled thru the oil return port with the piston blowby. I have used a second bottle to catch the return oil so I can see how much oil is being used. In this instance (OLD Saito 45 4S) one ounce of oil was drawn from the reservoir in 2 6oz tanks of GASOLINE at WOT (approximately 45 minutes). I think the neighbors are beginning to form a lynch mob.LOL. Approximately 2/3 of the oil was returned to the second bottle indicating that some oil was bypassing the ring/piston and being burned (the exhaust smelled a little like an worn out auto engine. No smoke was visible however! Probing the exhaust pipr with
a Q-tip showed NO oil residue. As I mentioned before, a teardown and inspection showed no indication of damace or wear nad the combustion chamber was not caboned at all.

Further testing will be done now with fuel to determine the best fuel to use gasoline? pure methanol? gas/alcohol blend? blend percentage? I believe this is going to work!!

Comments and suggestions and even criticisms are welcome.

Arceenut

It appears some of the pictures did not work. I'll try again

Arceenut

It appears the diagram was in the wrong format. Try again

dogshome

I have a couple of questions []

Valveguides and rocker gear.
Front main bearing.

The oil entry and return pipes are right next to each other, how is oil enticed into the main bearings? The same question goes for the valve guides. In the standard 4-stroke system oil seems to get everywhere by being in the inlet, exhaust and blowby. I'm not sure if your system is any better or worse than that though! [sm=72_72.gif]

Has this been done before on a 4 cycle engine? I'm thinking 1914.......

Patxipt

From the diagram attached, the spring on the check valve will determine the amount of pressurized oil to the front bearings before it is forced to the tank when the valve finally opens. It's pretty clever actually! Just a small adjustment on the spring will enable to build more or less pressure inside the engine to lubricate all the moving parts. There is always the piston ring for when the pressure is excessive, giving some margin for error.

But from the main topic, I thought it was a fully enclosed system, i.e., no externall oil tanks, all contained inside the engine - of course, this method would need a different ring to prevent oil blow-by from the sump to the combustion chamber.

Good job hamaoki![8D]

tkg

My Feedback: (1)

This has been done a few years ago when a bunch of guys flew a model across the Atlantic, before M Hill did it.
Things learned,
Bring the oil in to the front of the engine so that the cam, lifters and rockers get lubed.
Let the recovery tank act as a defoamer and then drain it back in the storage tank, use oil more than once.
Call up Frank Borman and get him to make a split set of rings. IE two rings in one grove with offset gaps to cut down on oil use.
Make sure that the engine moves oil at less than WOT.
HAVE FUN and don't give up your day job.

Arceenut

Dogshome I agree the oiling of the bearibngs and valve train would be no better/worse than the oiling by the blowby oil in the standard system. The purpose of this excesizi is not to improve the lubrication but to run the engine without the oily ehhaust mess.

Patxipt Good thought on the spring tension for pressure control. This is my first pass at this and possibly to reduce the pressure a different check valve i.e walbro carb may be a better solution. However the amount of oil bein passed to the combustion chamber even with this tired old engine seems to be small enough that it is being completely burned so that NO oil is present in the exhaust pipe after 45 minutes of running. I suppose the oil being burned in the combustion chamber could lead to carbon deposits and ring sticking but isn't a good 2s oil formulated to minimize carbon buildup? Certaily there is less oil now than with 20% oil in the fuel.

The only concern now is the reduction in cooling by the oil carrying off some of the heat. That is not a problem at the present as the ambient temp is around 0C (32F) at present but further testing and measurement will be done come warmer weather. The current engine temperature (measured with an infrared thermometer) is around 120deg C near the glow plug, 90 deg C on the head and 200deg C on the exhaust pipe.

Arceenut

Thanks for the info about Mr Hill. What was Mr hill's purpose of the excersize? Was it the need to reduce the amount of oil thrown out via the exhaust so that the fuel tank size could hold more fuel (distance)? Re bringing the oil to the front of the engine. I agree this would be better but the system now should be no worse that the original "blowby oiling" which seemed to work OK - the engine has many gallons of regular glo fuel thru it without any bearing or valve train problems.

dogshome

Has this not been done before in full size? I just read about rotaries - which was interesting! No throttle, total loss lubrication like our models... Surely some sort of vacuum lubrication MUST have been thought of 80 or more years ago?

The only drawbacks I can think of are; that you need to prime the system up to the jet; and there is a weight of oil and oil tank separate to the fuel. This tank would need to have a clunk in an flying airplane.

I do like the idea for the lack of smog and slime [sm=thumbs_up.gif]

Arceenut

Yes this is the type of system use in most aircraft piston engines. The system I believe is called a DRY SUMP system where the oil is held in a reservoir. In the case of the full size engines the oil pump feeds the bearings etc. by an oil pump and oil that bypasses the bearings is collected and pumped back into a tank. There is no sump in the engine like an auto engine oil pan. In my case the oil is fed into the crankcase and the bearings (con rod, mains, valve train) is "splash oiled" as with the blowby oil using normal glo fuel. The one way valve is a means to remove the excess oil from the crankcas back to the reservoir. The whole excersize is to run a model engine without passing a lot of oil out the exhaust and crankcase vent so that the model does not get "all gunked up" with the excess oil. Now, if I can lessen the oil leaking out the front bearing, my goals will have been met. Priming the system seems to be not necessary as the action of the piston and the one way valve creates enough of a vacuum to draw the oil up several inches. As to the extra weight of the oil, the system at present uses less than 1/3 oz of oil in approx 45 minutes of running so the tank can be very small (see photos). I can put up with an ounce of two of extra weight for the advantage of a clean airplane and if it works out, cheaper fuel.

Secondary to the excesize is the fuel used could be a more inexpensive fuel rather than the regular glo fuel which has reached over $20 agallon now and it would be nice to run the planes on regular gasoline or some fuel other than glo fuel.

Even if it does not work out, it is an interesting experiment and that is what I enjoy doing.

Patxipt

I really like this approach, although some basic machining skills are necessary for the backplate assembly with the pressure release ball valve.
I reckon the oil could be used several times if adequatelly filtered (i.e., 2 filters on return line, one in feed line).
I might try this one in the near future

Arceenut

Thanx for the encouragement. As for the filtering, if the initial oil supply was kept scrupulously clean, I am not considering filtering. At the small amounts of oil being used I would not think it would be necessary to reuse the oil a great number of times. Changing the oil after an hours use I think would be more than adequate to get rid of any contaminants. Even in this case of an old engine, it passed less than an ounce of oil thru the engine after 45 minutes of running WOT so changing the oil would not involve a lot of oil. Hopefully with a better seal by the rings, less oil would be burned and less blowby would contaminate the oil. Besides, filtering would only remove the solids and the only solids should be the wear materials from inside the engine which I hope would be minimal over the period of an oil change.

Next part of this experiment is to find a fuel that would run the engine reliably as glo fuel is not sold without oil and is getting expensive. I am hoping to run the engine on go-cart methanol or a gasoline/methanol mix with no oil. Possibly I may have to include some nitro in the mix to improve the idle or reliably. I am not looking for the last bit of HP. That is not the purpose of this excersize.

planepounder

hamaoki, you are chasing your tail. These engines are desigined to pass oil through out the engine and expell it out either the breather (vent) or the exhaust. A classic 4 srtoke maintains oil in the crankase for many hours/ miles. What you are doing is trying to recapture/ recirculate the oil. What you are recreating is a form of limited total loss oiling system. Why reinvent the wheel? I realize it is fun to experiment but your system is complex and and defeats the simplicity of the the 4 stroke glow engine. If you can build an engine that can run 100hrs between oil changes then you have just entered the industrial engine (lawnmower) age.

Arceenut

I guess you missed the point of my experiment. I am trying to come up with a system whereby I don' t have to spend an hour cleaning oil off of my plane at the end of the day. Not only is the clenup tedious but it getrs into the structure of the plane and on thew finish of the plane with detrimental results.

captinjohn

planepounder: I wish you was not such a kill-joy. Hamaoki is experimenting and that is how advances takes place. Keeping the spent oil out of the air is not a bad idea either. I took a 4 cycle .65 Saito and hooked a 2 oz tank to the crankcase overflow. You would be suprized how much oil accumilated in that tank. That is oil that would normally go all over your plane or in the air. Seems like the words "re-invent the wheel" and "chasing your tail" was used by you before on RCU. I think its a great idea to be able to use any fuel without the need to mix oil in the fuel. Capt,n

dogshome

A slightly random bit of information: The Austin 7 had a pumped and contained oil system with no filter. I wouldn't worry about the filtration on a run-in engine.

Thinking about the backplate machining: that could be avoided by using an inline check valve (YS or Perry) The only requirement then is to tap two takeoffs into the crankcase. One already exists on a Siato and the other could be done via one of the 4 backplate screws. The metering orifice could be a simple drilled bush inserted in the line.

Video of the running engine required please!

planepounder

Hey Capt,n, my apologies to hamaoki if I was blunt, I really did not mean to be. Maybe I overstated my thoughts. Yeah I hate cleaning planes too. But my 4 strokes are not too bad if you route the exhaust and breather the right direction, I realize some times it is not possible though. My later OS and Magnum engines recirculate it back into the intake which takes care of the breather problem. Hamaoki hang in there with your work! We all leave our experiments open to critical comments, these comments can be constructive. I think the jist of my reply was about the complexity. If you are flying larger 4 strokes, why not mod the rod and crank and run gas/glow?

av8tor1977

My Feedback: (6)

Volkswagen aircooled engines, from World War 2 up until some time in the 80's or 90's when they started making them in Mexico had no oil filter. Later engines made in Mexico had a filter, but many thousands of VW's ran many thousands of miles without an oil filter.

AV8TOR

Arceenut

Planepnder Apology accepted with thanx. Re the complexity of the system, I run a lot of planes in the 40 to 90 range. Not many or no engine of this size comes with con rods able to tale low oil. Machining and converting to roller bearings would be more difficult for me with my limited skills and lack of equipment. Machining the backplate is within my capabilities and NO mods to the engine are necessary.

Dogshome. & avi8tor Good idea about using an inline check valve. Thanx for agreeing with me re filtering.

Videos coming, have to get the fuel thing solved first.

Patxipt

A small thinking exercise.

Considering the system presented on our 4-strokes is basically a splash lubrication system, either with external oil tank (as nicelly shown and demonstrated here)or traditional fuel mixture, and considering most of the 4-stroke engines manufactured today use sealed front bearings, one could fill up the crankcase to a certain level with oil and by closing/removing the pressure nipple, oil would circulate throughout the engine parts, being forced back and forth by the pressure changes caused by the rising and falling piston. A wet sump system, if you like.
The backplate could be closed and used as an extra oil reservoir, only compensating for level changes due to blow-by and other small loses. Now that I think of it, it'd be roughly similar system to the one used on Honda's GX series[sm=idea.gif]
As a minus, as far as I can see, oil would tend to accumulate inside the rocker cover, and the valve stems/guides wouldn't be as well lubricated as they are by the fuel mixture we use traditionally during the intake and exhaust strokes.

planepounder

OK guys back in the discussion, hopefully a little more manerly. In an eariler post I stated the the glow 4 stroke is designed to eliminate is spent oil out the breather and exhaust. I was told by a fellow club member that these engines have a form of port from the crankcase to the cylinder to pass oil out throught the exhaust. As I posted earlier my Magnum .52 expelled all its spent oil out the exhaust when the breather got kinked. My concern is that unless this aspect of the design is addressed the engine would soon run out of oil unless a large amount was carried. What do you think?