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Car Forum / Jeep / June 2005OT a little 2 cycle Vs 4cycle
Just got rid of my 15 year old leaf blower. Something like a 30cc 16/1 mixture 15 year old Craftsman. Bought a new Poulan 40/1 33 cc blower. Question is the 2 cycle VS 4 cycle engine. What are the pros vs cons of both? I realize mixing oil & gas would be a hassle for most car owners but what other negatives are there for 2 cycle engines? I have to believe that power to weight ratio is very high for 2 cycle vs 4 cycle. Do 2 cycle engines wear more than 4 cycle? I guess I'm looking for the science behind these two types and how they lend themselves to automotive applications. Thanks, I appreciate the combined knowledge of the group. Brian Foster did pass the time by typing: > Just got rid of my 15 year old leaf blower. Something like a 30cc 16/1 > mixture 15 year old Craftsman. [quoted text clipped - 12 lines] > > Thanks, I appreciate the combined knowledge of the group. 2cycle produce power on each stroke, 4cycle produce power on each other stroke. For any given cubes a 2 cycle will outmatch the same sized 4cycle in not only power but power to weight ratio which is why 2cycles are used in BMX bikes. 2cycle burns oil so they pollute more. Newer engines are better and there are some very good boat motors out there. Also in 2cycle plugs foul real quick. http://science.howstuffworks.com/two-stroke.htm  SignatureDougW Emissions primarily ; 2 stroke engines are more dirty as some of the oil put in for lubrication gets burnt. However, they tend to be higher output as they can fire twice as often. Don't know about wear ; would guess that 2 strokes would wear faster, both because of the oil and also because of the output. Dave Milne, Scotland '91 Grand Wagoneer, '99 TJ > Just got rid of my 15 year old leaf blower. Something like a 30cc 16/1 > mixture 15 year old Craftsman. [quoted text clipped - 12 lines] > > Thanks, I appreciate the combined knowledge of the group. Two cycles are too dirty, and use way more fuel, even then in bigger engines you need a way for them to breath, needing both turbo and super chargers, and four valves per cylinder like the 1947 Detroit 6-71 still being used in diesel trucks with twelve cylinders, 92 cubic inches per cylinder: http://blakeboatworks.com/janbill.jpg God Bless America, ßill O|||||||O mailto:LWHughes3rd@aol.com http://www.billhughes.com/ > Just got rid of my 15 year old leaf blower. Something like a 30cc 16/1 > mixture 15 year old Craftsman. [quoted text clipped - 12 lines] > > Thanks, I appreciate the combined knowledge of the group. The two cycle crankcase scavenged engine used in snow blowers, model airplanes, chain saws, has nothing to do with two cycle diesels which run dry crankcases and use plenum scavenging with a Roots (most Detroits) or centrifugal (Foden, a few odd Detroits, Junkers Jumo). Two cycle spark engines using direct injection and pressure oiling with synthetic oils are much, much cleaner than they were years ago, which is the only reason they are still allowed in outboards. You don't know much about Detroit Diesels either. A 6-71 does not have 92 cid/cyl and does not have twelve pistons. A 12V-92 does. Turbocharged two cycle diesels only use the mechanical Roots blower for starting, as the turbos maintain positive plenum pressure from there out. In fact racing Detroits now have no mechanical blower-they use air impingement for starting. it may interest you to know that the ONLY Detroit Diesel engine meeting the most stringent new heavy vehicle standards for emissions is the 6V92T DDEC. The Poster was not asking about chain saws, or motorbike engines, but why two cycles couldn't be use on a larger scale. And that answer again is pollution: http://www.dieselnet.com/standards/us/light.html and diesel-powered cars are banned in California: http://www.detnews.com/2005/autosinsider/0501/06/C02-51826.htm As an owner operator I've adjusted the rack and changed the buttons on every tractor I've driven, even did a few in frames on my trucks: http://www.billhughes.com/rextrans.jpg http://www.billhughes.com/kenworth.jpg http://www.billhughes.com/white.jpg http://www.billhughes.com/mack.jpg I bet you can't tell me what a button or rack is! God Bless America, ßill O|||||||O mailto:LWHughes3rd@aol.com http://www.billhughes.com/ > The two cycle crankcase scavenged engine used in snow blowers, model > airplanes, chain saws, has nothing to do with two cycle diesels which [quoted text clipped - 14 lines] > meeting the most stringent new heavy vehicle standards for emissions is > the 6V92T DDEC. How much you want to bet? Took you long enough to look it up. God Bless America, ßill O|||||||O mailto:LWHughes3rd@aol.com http://www.billhughes.com/ > How much you want to bet? No, I was just off line. I had other stuff to do like work. "Buttons" are used in the Cummins PT system. Detroits have a unit injector that is connected to a shaft and bellcrank affair that is operated by a rod off the governor. "Running the rack" refers to setting the injector slides up so they are all even in travel so all cylinders get the same fuel. When the engine is converted to DDEC the rack and its linkages are removed. I'm told the very first Series 60 engines have little flat areas in the casting so that if DDEC hadn't worked out they could have went mechanical via field conversion. Correct. God Bless America, ßill O|||||||O mailto:LWHughes3rd@aol.com http://www.billhughes.com/ > No, I was just off line. I had other stuff to do like work. > [quoted text clipped - 8 lines] > the casting so that if DDEC hadn't worked out they could have went > mechanical via field conversion. > Just got rid of my 15 year old leaf blower. Something like a 30cc 16/1 > mixture 15 year old Craftsman. [quoted text clipped - 4 lines] > both? I realize mixing oil & gas would be a hassle for most car owners but > what other negatives are there for 2 cycle engines? They stink, they smell bad, and they smoke. They have a bitch of a time passing the smog laws of pretty much everywhere, and they stink, smell bad, and smoke. Mixing gas and oil is not biggie, the major manufacturers figured out a very long time ago how to meter the oil into the fuel supply, so the operator simply adds gas to one tank and oil to another, and the rest magicly happens all by itself. But, none of this gets around the stench, the stink, and the smell. Then, there's the noise. > I have to believe that power to weight ratio is very high for 2 cycle vs 4 > cycle. Do 2 cycle engines wear more than 4 cycle? [quoted text clipped - 3 lines] > > Thanks, I appreciate the combined knowledge of the group. They're using the two cycle tone ringer for cell phones in Europe. God Bless America, ßill O|||||||O mailto:LWHughes3rd@aol.com http://www.billhughes.com/ > They stink, they smell bad, and they smoke. They have a bitch of a time > passing the smog laws of pretty much everywhere, and they stink, smell bad, [quoted text clipped - 3 lines] > magicly happens all by itself. But, none of this gets around the stench, the > stink, and the smell. Then, there's the noise. Where do you mix the oil in a cell phone? > They're using the two cycle tone ringer for cell phones in Europe. > God Bless America, ßill O|||||||O [quoted text clipped - 7 lines] > > magicly happens all by itself. But, none of this gets around the stench, the > > stink, and the smell. Then, there's the noise. LOL Don't say that in a room of avid snowmobilers. Theirs nothing like the smell of a 2 stroke on a crispy -15 degree C winter morning. AHHHHHH :-) Can't wait ( beats this +32C humidity crap) It's amazing the HP that comes out of my little half liter 2 stroke engine. around 75HP I believe. > They stink, they smell bad, and they smoke. They have a bitch of a time > passing the smog laws of pretty much everywhere, and they stink, smell bad, [quoted text clipped - 3 lines] > magicly happens all by itself. But, none of this gets around the stench, the > stink, and the smell. Then, there's the noise. Along with everything else that has come up, two stroke engines may produce more power per pound, but they have a very narrow power band. I believe this applies to the Detroits as well, that's why they have like 400 gears. It is also why they are used in things that run at one speed, usually wide open (chainsaws, weedeaters,etc). Snowmobile pulleys keep the engine in that band as long as possible. The other advantage of the two stroke is that they can run at any angle. > Just got rid of my 15 year old leaf blower. Something like a 30cc 16/1 > mixture 15 year old Craftsman. [quoted text clipped - 12 lines] > > Thanks, I appreciate the combined knowledge of the group. > The other advantage of the two stroke is > that they can run at any angle. Uh, that might *really* be an advantage in an off road situation. :-) -- Old Crow '82 FLTC 92" 'Pearl' '95 Jeep YJ Rio Grande SENS, TOMKAT, BS#133, DOF#51, MAMBM Until you learn you have to lay your jeep on it's side to clean it out. God Bless America, ßill O|||||||O mailto:LWHughes3rd@aol.com http://www.billhughes.com/ > Uh, that might *really* be an advantage in an off road situation. :-) > [quoted text clipped - 3 lines] > '95 Jeep YJ Rio Grande > SENS, TOMKAT, BS#133, DOF#51, MAMBM L.W. Hughes III (ßill) wrote: > Until you learn you have to lay your jeep on it's side to clean it > out. Nah, I just run it slowly through a really deep water crossing<g>. Still it'd be nice to turn it over and have it still run. -- Old Crow '95 Wrangler Rio Grande > Until you learn you have to lay your jeep on it's side to clean it > out. Clean it out, or empty it out? Either way, I'm not clear on what the down side is. > Along with everything else that has come up, two stroke engines may produce > more power per pound, but they have a very narrow power band. I believe > this applies to the Detroits as well, that's why they have like 400 gears. > It is also why they are used in things that run at one speed, usually wide > open (chainsaws, weedeaters,etc). Snowmobile pulleys keep the engine in > that band as long as possible. The other advantage of the two stroke is > that they can run at any angle. This feature would seemingly make them ideal for a Jeep. Of couser, a Jeep with 400 gears would suck. |
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