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Peryn · 10-31-2003, 10:28 AM

I dont want to be too rude, but Ziadel, you have no idea what you are talking about. Your freind doesn't seem too informed either...or he doesn't know how to take care of his car.

As for the how a rotary works, howstuffworks is an awesome site. Anyway, as a kid did you ever play with Spirograph or something like that? It had various gear looking things you put in each other, spun your pin around and it make a cool design. It works just like one of those. As the triangle spins, it end up spinning a gear in the middle. This is the equivelent of your Crankshaft.

Anyway, while it hasn't had near the R&D that a piston engine has, i think it is a far superior design. It uses essentially 3 moving parts (2 rotors, and an eccentric shaft). Whereas a piston engine uses hundreds (pistons, connecting rods, cranks, cams, distrib, valves, springs, etc..). This means there is far less that can break or go bad, making it pretty cheap to fix back up. Also to me it makes more sense from a logical standpoint. If you want to spin a rod (turn the crank) ... doesn't it make more sense to spin the rod directly, than make a bunch of pistions move up and down, and then convert that to a spinning motion? It just seems easier and a better idea to make your combustion directly spin a shaft than have to conver reciprocating motion to a twisting motion.

Yet another advantage is weight. A rotary produces for more power for its weight and size than probably any other motor on the planet. (well, for the most part). Even if you do have to worry about CA emissions (pretty much the harest emissions to pass), you can make the power of a v6 or some v8's out of an engine the size of a small 4 cyl, maybe even a large 3 cyl. If emissions aren't an issue, the rotary is by far the best way to make monster power out of a small powerhouse. TT setups like the 13b-REW can make 500 horses without too much problem. And with the piping its still pretty much the size/weight of a typical 4 banger.

Another advantage is the shape of the engine. Because you spin the shaft directly, in a circular motion, the weight of the engine is in a fairly small circle around the shaft. This means it doesn't have cams, cylinderwalls, valve covers, etc. to make the weight of the engine much higher than teh crankshaft. So it sits down much lower in the car and, combine with its short length, makes for a much lower, shorter, lighter position of the engine, dramatically helping the Center of Gravity of the car its in. Hence the reason the RX-7's handle so unbelievably well.

There are a few disadvantaged though with it. These can be a kinda big deal if you know nothing about cars and are in no way mechanically inclined.

Oil : due to the nature of the engine, they burn a little oil in teh combustion chamber. Because of this, you need to be very good with your maintenance, and keep oil in it. Also, you need to keep an eye on how fast your burning it, to make sure nothing else is wrong. You also must change your oil regularly. Cant really afford too much to wait an extra 1-2k between changes, or you will shorten your engine life. Also, you hafta get used to seeing smoke out the tailpipes when you start it up...sometimes a LOT of smoke.

Mechanical Knowledge : It helps a lot if you work on your own car. Not many people know how a rotary works, let alone are qualified to touch or even work on them. It is hard to find a good mechanic to work on your car that wont make the situation worse, and when you do, be prepared to pay for it. Parts aren't too bad (though mazda parts are ALWAYS more expensive than other manuf.'s), but you will pay big time for his labor.

Reliability : They tend to be very reliable engines if you take car of them. Well, for the first 100-120k they are. Then chances are you will need to take out the engine and replace some of the seals internally. The apex seal doesn't last too long. Someone was saying his cars wouldn't last more than 60k miles, that about 1/2 what it normally lasts. Either he wasn't taking very good care of his cars, or he was getting cars that were neglected. Its really not too bad to rebuild the engine and its seals (and as long as your at it, do some porting to get more power out of it) but most people find it a large anoyance, and thus label the engines as a POS.

Overheating : The rotary has some aluminum housings. As such, you CANNOT let it overheat. They actually have a very capable cooling system, and this will probably never be an issue unlesss your radiator blows, but engine death can occur if you drive it while its overheating. Another reason most common people think its a bad engine, is they hafta be so careful about that. Of course its really not much different than other aluminum engines. They will have very bad problems as well if you let them overheat.

There is probably more im missing, or some facts i might have messed up. I just got up, so who knows what i wrote... im a zombie right now. What it basically comes down to is i like a rotary very much. They are also pretty reliable if you are willing to throw some rutine maintenece at your car, and learn what it needs to be taken care of.

Oh another thing, rotaries then to be not as clean as piston engines these days. They also dont get great gas mileage. On a more positive note, they respond much better to basic airflow increases than almost any piston engine will....even the turbo ones. People claim to get upwards of 10-15 HP with a very good intake, headers, and exhaust system on a piston car. you could probably realistically get 20-25 off of a good intake/exhaust system with a rotary. Also, rotaries dont make any low end torque unless you get into a 3 or 4 rotor. They also rev very high, and very fast.

10-31-2003, 10:28 AM	#7 (permalink)
Peryn Junkie Location: San Diego, CA.	I dont want to be too rude, but Ziadel, you have no idea what you are talking about. Your freind doesn't seem too informed either...or he doesn't know how to take care of his car. As for the how a rotary works, howstuffworks is an awesome site. Anyway, as a kid did you ever play with Spirograph or something like that? It had various gear looking things you put in each other, spun your pin around and it make a cool design. It works just like one of those. As the triangle spins, it end up spinning a gear in the middle. This is the equivelent of your Crankshaft. Anyway, while it hasn't had near the R&D that a piston engine has, i think it is a far superior design. It uses essentially 3 moving parts (2 rotors, and an eccentric shaft). Whereas a piston engine uses hundreds (pistons, connecting rods, cranks, cams, distrib, valves, springs, etc..). This means there is far less that can break or go bad, making it pretty cheap to fix back up. Also to me it makes more sense from a logical standpoint. If you want to spin a rod (turn the crank) ... doesn't it make more sense to spin the rod directly, than make a bunch of pistions move up and down, and then convert that to a spinning motion? It just seems easier and a better idea to make your combustion directly spin a shaft than have to conver reciprocating motion to a twisting motion. Yet another advantage is weight. A rotary produces for more power for its weight and size than probably any other motor on the planet. (well, for the most part). Even if you do have to worry about CA emissions (pretty much the harest emissions to pass), you can make the power of a v6 or some v8's out of an engine the size of a small 4 cyl, maybe even a large 3 cyl. If emissions aren't an issue, the rotary is by far the best way to make monster power out of a small powerhouse. TT setups like the 13b-REW can make 500 horses without too much problem. And with the piping its still pretty much the size/weight of a typical 4 banger. Another advantage is the shape of the engine. Because you spin the shaft directly, in a circular motion, the weight of the engine is in a fairly small circle around the shaft. This means it doesn't have cams, cylinderwalls, valve covers, etc. to make the weight of the engine much higher than teh crankshaft. So it sits down much lower in the car and, combine with its short length, makes for a much lower, shorter, lighter position of the engine, dramatically helping the Center of Gravity of the car its in. Hence the reason the RX-7's handle so unbelievably well. There are a few disadvantaged though with it. These can be a kinda big deal if you know nothing about cars and are in no way mechanically inclined. Oil : due to the nature of the engine, they burn a little oil in teh combustion chamber. Because of this, you need to be very good with your maintenance, and keep oil in it. Also, you need to keep an eye on how fast your burning it, to make sure nothing else is wrong. You also must change your oil regularly. Cant really afford too much to wait an extra 1-2k between changes, or you will shorten your engine life. Also, you hafta get used to seeing smoke out the tailpipes when you start it up...sometimes a LOT of smoke. Mechanical Knowledge : It helps a lot if you work on your own car. Not many people know how a rotary works, let alone are qualified to touch or even work on them. It is hard to find a good mechanic to work on your car that wont make the situation worse, and when you do, be prepared to pay for it. Parts aren't too bad (though mazda parts are ALWAYS more expensive than other manuf.'s), but you will pay big time for his labor. Reliability : They tend to be very reliable engines if you take car of them. Well, for the first 100-120k they are. Then chances are you will need to take out the engine and replace some of the seals internally. The apex seal doesn't last too long. Someone was saying his cars wouldn't last more than 60k miles, that about 1/2 what it normally lasts. Either he wasn't taking very good care of his cars, or he was getting cars that were neglected. Its really not too bad to rebuild the engine and its seals (and as long as your at it, do some porting to get more power out of it) but most people find it a large anoyance, and thus label the engines as a POS. Overheating : The rotary has some aluminum housings. As such, you CANNOT let it overheat. They actually have a very capable cooling system, and this will probably never be an issue unlesss your radiator blows, but engine death can occur if you drive it while its overheating. Another reason most common people think its a bad engine, is they hafta be so careful about that. Of course its really not much different than other aluminum engines. They will have very bad problems as well if you let them overheat. There is probably more im missing, or some facts i might have messed up. I just got up, so who knows what i wrote... im a zombie right now. What it basically comes down to is i like a rotary very much. They are also pretty reliable if you are willing to throw some rutine maintenece at your car, and learn what it needs to be taken care of. Oh another thing, rotaries then to be not as clean as piston engines these days. They also dont get great gas mileage. On a more positive note, they respond much better to basic airflow increases than almost any piston engine will....even the turbo ones. People claim to get upwards of 10-15 HP with a very good intake, headers, and exhaust system on a piston car. you could probably realistically get 20-25 off of a good intake/exhaust system with a rotary. Also, rotaries dont make any low end torque unless you get into a 3 or 4 rotor. They also rev very high, and very fast. __________________ Dont cry kid, It's not your fault you suck.