Osirisf16

I kinow, somehow, what is each of these but to complete my knowledge, i want if anybody of you knows MORE can tell me. Share please

Foxy

Not sure what you want to know here... 4 stroke means the ignition timing is such that the cylinder fires every 4 rotations, whereas with a 2 stroke, it fires every two rotations. 4 strokes thus far are the domain of large scale planes as far as I know.

tmdz28

share what? [&:]

ttoks

a 4 stroke uses less fuel, is usually quieter, more bottom end torque and is most cases more reliable.

sheograth

The easiest way to understand the difference would be to google it up and you'll find a good animation probably. That'll show the dynamic of how the plug fires in relation to the piston, and what is happening during each part of the cycle. A 2 stroke engine fires every time the piston reaches TDC. The compression stroke is the same as the intake stroke, as the piston compresses the fuel/air above, it draws more into the crankcase from the carb. The power stroke is the same stroke as the exhaust, as the piston moves down the case it opens up a port and the spent mixure flows out.

tmdz28

http://science.howstuffworks.com/two-stroke6.htm

stempak

They are just like car motors or anyother 4stroke they have valves and a camshaft. it basicly takes 2twice the cc's to make the same power as a 2stroke. But as stated above they are quiter, smother and more dependable also run better. They are being used in boats currently with topspeeds in the 50's were as the 2 strokes are doing 70+ with records over 100

ttoks

really i think that a good 4 stroke will make about 70% of the power of a similar displacement two stroke because they are more efficient, and lets not forget that if you so desire you can used forced induction on a 4 stroke...

sheograth

Yeah I dont know the specifics but I definitely don't think its only half the power of the equal displacement in a 2 stroke. Again, it all depends on the specific design of the engines you're comparing.

vtl1180ny

You can use forced induction on a 2 stroke also, it's just more difficult... Detroit Diesel engines are 2 stroke and either turbocharged or supercharged... They have an intake port and an exhaust valve...

I'm sure the global warming crowd will soon be working to outlaw every 2 cycle engine including the ones we use...

ttoks

the key word there is valves, these engines don't use valves, forced induction on loop scavenging two stroke is pointless.

to curb the global warming crowed, we need direct injection lol, no hydrocarbons out the exhaust that way, jet skies and snow mobiles have it already so it wont be to long i don't think...

vtl1180ny

You are wrong... Many people put Reed valves on their engines... The little Nitro engines do have an Intake valve, it's in the crankshaft...

The days of burning oil and gas mix are going to quickly come to an end...

ttoks

sorry, my fault there, let me clarify what i meant by valves, in the cylinder, all the big two stroke diesels use an exhaust valve in the head, which allows the exhaust to open before the intake and allow for scavenging, and close before the intake and allow boost pressure to build, the reed valve is in the crankcase controlling the flow into the crankcase, not directly controlling the fluid flow in the cylinder, and then it only reacts to changes in pressure, it's not mechanically driven, loop scavenging the exhaust opens before the intake, and closes after which doesn't allow for much room for boost to build, can be done but has been proven many times on glow engines to be ineffective.

stempak

They are using a honda gx31and 35cc I believe in the boats. And they also working on forced induction bigger cams ,valves etc. but currently 50's is tops compared to 20's a few years ago. Eventually I'm sure they'll make it over here. They also run really well on nitro in planes and have miny supercharges that work just like the full size.

ttoks

the O.S plane engines that are supercharged are 4 stroke, as are the honda gx25 and 35 cc engines, my weed whacker is the 25 cc version of that engine, not sure how it would go with forced induction as they use a single cam lobe for both the intake and exhaust, doest give much room for modifying the timing.

Osirisf16

Don't say that, like its the end of the world. I'm 17 years old and i don't care about this matter because the gas in earth is going to last about a 80 years...

Billyfunnyguy

That 80 years is the amount that is being pumped now you have many more then that if drilling elsewhere.[:-]

ttoks

at hte current time, only 13% of the world oil resources are considered usable, theres a lot out there to be found still.

vtl1180ny

I'm not talking about Gasoline... I'm talking about 2 cycle engines, they are an endangered species... Notice how ATV's and Dirtbikes are all going 4 stroke? The tree huggers want 2 cycles engines gone...

Foxy

Yes, I've done quite some research on this, and the people who say there's not much oil left are totally wrong. Recent independent estimates, based ont he distribution of oil that we HAVE found, indicates there could be anything from 150-500 years of oil left. Of course we need to curb our usage of it, but the situation is not as bad as they say. Of course this is not a good thing for global warming, means it will continue. Means the oil Sheikhs will stay rich and continue to block production and development of alternative fuels wherever they can. There's a perfectly serviceable engine on the drawing board right now, which converts sea water into electricity, and offers similar performance to petrol. Of course the tech is too expensive right now to consider mass production, but that's the way it's going. Sea water.

ttoks

most atv's an dirtbikes are going 4 stroke because 4 stroke is faster believe it or not, a honda CRF 450R is a faster race bike then a CR 250 because it has so much usable power, maybe someone should have a look into 30cc force fed 4 stroke's for our rc's, oh yeah that sounds good to me.

in my opinion the direct injection technology being used on jet skies is all RC engines need to curb the emissions problem, of course that means computers though which make things complicated, unreliable and expensive...

stempak

What happens when a cr500 pulls up? The 450 gets it's door's blown off.

vtl1180ny

4 strokes require almost double the displacement than a 2 stroke to produce the same HP, 4 strokes do produce much more torque though... They aren't going 4 stroke because of power... They had to make it a 450 because of the lack of power... 2 strokes are being eliminated because of the emissions... Let's face the facts The US buys more than every other country and probably more than some whole continents... Our Environmental protection Agency is slowly outlawing 2 stroke engines, what we do affects the world...

ttoks

i give up... it would be more effective to ban fishing then switching to 4 stroke bikes to curb emissions, seriously, emissions is not the reason so many guys are turning to 4 stroke rather then 2, and it aint just the pro levels either.

Billyfunnyguy

Um, try reading this may help both sides.

http://www.deepscience.com/articles/engines.html