I'm sorry I was a little off t66 turbo low compression turbo 2 rotors re block 4 port 480 hp at 8000 rpm..
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I'm sorry I was a little off t66 turbo low compression turbo 2 rotors re block 4 port 480 hp at 8000 rpm..
OK guys enough. This is my thread about the OMC rotary race engine, not modified Mazda's. I enjoy seeing your stuff, but start your own thread. Thanks
Sorry, I never intended to Jack your thread,Quote:
Originally Posted by Rotary John
I have gone to see what happened to the OMC motor at Moller in Davis,ca
I only wish I could get a rotary powered outboard !
The only thing left is making one myself out of whats been made
You guys were on the right track decades ago
Thank you for your posts !
If you have any ideas on putting a Rotary O/B together
I would like to here them
I read the complete thread on Boat racing facts, a while back "09
And have been motivated by it. To research everything Rotary
You lit A fire that just won't go out !
Thank you again
Big Steve
Somebody in oz has the rotary to merc adapter plate
So thats part of tne job done
I have always doubted this claim, so I asked Charlie Strang. Here is his response:Quote:
Originally Posted by LIQUID NIRVANA
Quote:
Dear Sam:
I'm afraid the story about the reputed cleanliness if the rotary is a figment of someone's over active imagination! The primary problem with the engine was its extreme dirtiness. The long, flat combustion chamber created by the rotor in its somewhat triangular housing resulted in a "wet chamber" that could be cleaned up to meet coming pollution standards only by adding a very expensive catalytic converter to the exhaust system.
Aside from being dirty, the engine was expensive to manufacture because of the tool steel seals it required for any kind of life and the very expensive alloy coating needed in the trichinosis housing to withstand the wear created by the seals.
When all was said and done it was far less costly to build a direct-injected two-cycle piston engine or even a four-cycle engine to meet the emerging clean exhaust laws.
As far as I know, OMC was the only company in the USA or North America ever to put a rotary into actual production. We built several thousand single-rotor engines and sold them in snowmobiles just before the onset of new exhaust laws finished the day of the Wankel. All in all. the engine was fun to work with --including our four-rotor racing engines -- but in the end it amounted to one big and expensive waste of time!!
Regards, Chas S.
PS: In answer to one of your questions which I overlooked, yes-we constantly analyzed the rotary engine emissions, always seeking to improve them --without success.
Mr Strang meant to say trochoidal, not trichinosis (a parasitic infection), in reference to rotor housing shape. Rotaries are not only very "dirty" emissions wise due to the inefficient long convex rectangle shape of the rotor face that contains the combustion chamber, they also have extremely high EGTs due to the fact that the exhaust port is never closed... there is always a rotor face on "exhaust stroke". As noted above, the seals are also a tripping point due to friction, wear, and the fact that if they are hard enough to survive they are brittle enough to be fractured by detonation, which is a constant problem. It's easy to seal a round bore piston and use cylinder pressure to force the seal to do its job, Rotaries have to use springs behind the seals - apex, side, and corner, and they lose effectiveness with heat and wear. The "you can turn one 10 grand all day" deal is another wives tale - revs kill rotaries even faster than their piston counterparts - I'll bet on a Honda F20 vs a Renesis turning 9K all day long with regard to durability. The last RX7s were redlined at 7 grand, and for good reason. Yes racing engines can get away with it for brief periods, but rotor bearings, housings, and especially end housings get the hell beat out of them by high RPMs because of eccentric shaft flex.
Bottom line... They are fun to play with and can make impressive power for their size, but efficiency and durability shouldn't be used in the same sentence with rotary.
Rotor fans, please dont take any of this the wrong way, I like them. They are part of how I make a living. Just wanted to clear up some BS misconceptions. I also don't want to crap up Rotary John's thread - I think the OMC rotaries were a phenomenal piece of engineering, especially at that time, and applaud those guys for the effort.
The enginee has a bad surface to volume ratio so bad nox
This was explained to us omc service schools and of course we had the mazda in oz and the 70' saw the start of emission regs in cars so we knew
Direct injection might give it another life
Doesn't that give new rotor seal lube problems?Quote:
Originally Posted by powerabout
I have never studied a rotary so I dont know all the issues but for sure there are plenty in my old home town that knowQuote:
Originally Posted by Mark75H
Maybe we will see an E-tec Rotary??
An E-tec crossflow would be a great work horse
FYI
http://www.riceracing.com.au/apex-seals.htm
Now----if I was a BASTY nastard (which I am not) I would be chortling and rolling all over the hog market after reading C/S's insight into the ROTORY project.
Out of the mouths of babes and presidents etc.etc.etc.
Not only is it a mucky motor, it's totally non-viable, never has been, never will be, not cost effective, not economical, Jesus H, C expensive and a heartbreaker to dedicated engineers.
After more than a hundred years, you would think that the penny would drop, the damn thing is fatally flawed, I know that Hope reigns eternal and all that but the design needs binning.
Jackie
Think you need to do a phd on the rotary
All that research will give you something to do
For your proposal you could do either why they work or why they dont work
Same job as you will still need the same evidence
Cheers
So a fresh, low RPM rotary is a decent, if dirty, motor? Ours was traded in with low mileage...but man it was a rocketship while we had it... Kind of a shame really..given the simplicity of the design.
Its amazing to me all the engineering experts on this subject that are so full of crap, including Strang. Rotaries are low on NOx due to lower combustion temps and high on HC due to surface to volume ratios (quench surfaces) as compared to 4-strokes. Exhaust temps are high due to more complete combustion and are similar to a 4-stroke. The heat generated in the exhaust system is indeed more for a rotary as it is continually exhausting. A 4-stroke only exhausts for approx. 90 degrees of crank rotation and then gets to wait for another complete crank revolution before it happens again. A 2-stroke has lower exhaust temp due to poorer and less complete combustion and the dilution caused by over scavenging. Strang must have been too busy running OMC into the ground to look at the emission testing results we were doing in the early '70's. As compared to a cross scavenged 2-stroke, untreated, the rotary had 10 times less HC. When treated with a thermal reactor with added air, that figure dropped to 100 times less. He was also apparently unaware we had sintered metal apex seal for about a nickel apiece. He spent money on production machinery from Gleason Works for side seal machining and trochoid grinders; just to have fun? There were no emission requirements for outboards or snowmobiles in the early /middle '70's. The first non-automotive emission requirement in the US was Calf. (not Federal) in 1974 that banned 2-stroke motor cycles. California has tested the water cooled version of the 530cc OMC engine from Moller that meets the ultra-low emission certification without any after treatment on pump gasoline. Charlie's memory is his justification pursuing 2-strokes, as oppose to developing emission technology for the forthcoming emission laws regardless if it was direct injected 2-strokes, 4-strokes or rotaries. He didn't and was forced into the disaster that bankrupted OMC. The 4-rotor race engine served his purpose; "Beat Mercury"; which it did very nicely. Once he had the 150ci V-6 to compete with Merc's 122ci engine and didn't need the rotary anymore. Witness the fact that all the Marine Engineering Rotary people; san 1; left the company, including the manager, and all rotary engine development was stopped by 1976. Prior to ANY outboard emission laws. Oh, by the way the Graupner rotary is rated at 18,00/22,000 RPM.
SpEED FAB.... you are very knowledgeable and speak like a true gentlemen i wish everyone could converse like you...but for the emissions on a race engine?? lol. All these stories, fails and bad a pex seals are from the70s. They didn't even invent the cassette player yet... lol Anytime the rotary has raced against piston engines it's kicked butt.. and all the people who don't like them say they blow up or drink fuel... so do mercs i mean that's crazy it's performance we are looking for not a prius right??? And what i just wrote wasn't directed at u . Please don't think I'm pointing fingers u have very good points. Ps renesis motor is junk i know lol..
Hi Knot, and thanks. I only mentioned emissions because the post above mine did... And like Rotary John said, their only real emission problem is from hydrocarbons, as a result of incomplete burn in that long rectangular "combustion chamber"... In comparing one to a TWO STROKE, and especially a pre-DI one running on premix, that's a totally moot point. This long chamber with corners and poor quench is part of the reason the Mazdas have leading and trailing sparkplugs for each rotor. They are actually somewhat better than most other engines with regard to oxides of nitrogen... they have an inherent form of inbuilt EGR as the chamber on each rotor face naturally carries some exhaust back around with it after the apex seal closes the exhaust port, and the combustion temps are lower. Apex seal problems predate the 70s, exist right now, and will continue until someone finds some magic unobtanium and pixie dust from which to make them. These engines ARE fragile in comparison to piston engines, make no mistake, and running them rich enough to be safe is part of the fuel consumption issue. They have a very low tolerance for tuning issues, lean mixtures, and excessive spark timing... You can rattle some piston engines all day on bad gas, but you damn sure can't do it to a rotary.
I'll take Rotary John's real life knowledge of these things over internet armchair quarterbacks and rotary fanboys all day. I may have many years of experience with them, I may be an engineer, but he actually ENGINEERED one. Big difference. I'm not just blowing smoke, I think everyone reading this needs to realize how fortunate we are that he is actually here telling us about it. I find the whole thing fascinating.