"is designed for blow by oiling" meaning there is no oil sump or tank. You have to think about cost to manufacture, complexity, reliability, etc... A prop kick back might shear the oil pump drive key and and you'd never know it untill the engine fried. Then you send it back to the manufacturer for repair. "They don't want that. "They" want to sell alot of engines, "They" want to come out with new models that allow them to discontinue the older ones so you can't get parts anymore.

I have no doubt that "they" could make a model airplane engine with a pressurized oiling system that would last a very long time but there's no money in it.

There is such an engine made by Kavan, a 50cc engine with oil in the crankcase.

Part of the attraction of the four stroke model engines is their relative simplicity and that they operate very much like the 2 stroke engines with generally the same fuel.

http://www.mecoa.com/kavan/index.htm $7,500.00, holymoly.

Some of the four stroke weed whacker engines have a slinger or impeller that throws crankcase oil around in the crankcase and circulates it by the rocker arms so that the engine can be used in all positions.

Even the 50cc fourstroke gas engine sold by rc showcase uses blowby and a 32:1 oil blend.

It would seem that your question was rhetorical as you know all the answers. Just what is the yalue of "your" thread?

jess

[8D]

I did not say you could do that! I said you could design an engine as large as you wanted with gas/oil mix. Of course an engine with soft babbit journals will not hold up to a fuel oil mix. They will be ruined in a matter of minutes. An engine that size would need ball bearings made for this purpose. Engines as large or larger than a small block Chevy has been made with mixed fuel oil before.

car engines have a bit of blow by. My car has three rings a high compression ratio and the oil still manages to blow by and burn. my question is when its so much lighter weight to have a oil system in fuel why would you want an oil system like what cars have? and it adds a level of complexity that makes more moving parts to break down.

Some outboard boat engines and motor cycle engines are (were) 2 cycle with the boat engines maybe upwards of 200 hp. I never owned one but I think they had oil injection which resulted in a sacrificial usage of the oil.

Don't forget the old Saab automobile 2 stroke popcorn popper engines from back in the 60's. They performed very well with years of service.

that gives me an idea to save money at the theaters

I had a Kawasaki 500 triple that had oil injection (2 stroke). Racers got over 100 HP out of them, and many converted to premix for simplicity. It had a HP curve that would make MT. Everest look like an ant hill.

Burning the oil can cause problems, mainly carbon.

You would simply run fuel oil mix up to the rockers, or use blow by from the valve stems. This is not a new trick larger engines ( in displacement) than a Chevy small block have used once through or blow by oiling systems. They also had valves and rockers to deal with.

Too dark to be rust. Just oil stains.

Gasoline is now $4.00 a gallon, but what some may not know is that motor oil is now almost $4.00 a quart. Not the synthetic oil either. So if you mix 20 gallons of fuel with say 50:1 thats 1.6 quarts or $6.40 of oil. If the vehicle gets 20 miles to the gallon thats 24 quarts of oil compaired to say four or five quarts every 6,000 miles. I suspect a larger engine may require higher ratio's of oil. That is why we don't use once through oil systems.

BTW they had two strok SAAB's that had oil mixed in the fuel. I think they added about a quart to a 10 gallon tank.

Thanks Hugh, you're spot on, woops, no pun, that engine is 17 years old and deserves to have a few imperfections. It still turns a Scimitar 13x6 at 9,700.

Now that was a motorcycle! My dad had two of them. One was stock and the other was the one with expansion chamber pipes and wheelie bars. The HP curve was unbelieveable.

I didn't know they popped corn either. Did you hold the bag to the heat outlet to get the popcorn?[sm=idea.gif]

They called the Saabs popcorn poppers in my area because of the the way they sounded.

I grew up in a college town and there were a lot of them.

I was just saying it sparked an idea to pop my own using the engine heat on the way to the theater sneak the popcorn in and i am getting more done with my engine lol

At one time I had a 200 HP outboard, but it used pre-mix. Oil injected outboards came along a bit later but by then I had tired of pouring money into a hole in the water.

jess