new rotary engine trouble ?

In message , Guy King writes

I knew exactly what you meant Guy :)

Reply to
Paul Giverin
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The Chrysler turbine cars had a full-length exhaust system, just like a piston engine car. The "dumps" were just below the rear bumper. It was a dual exhaust system, with each exhaust pipe being fed by the gas flow over one of the two regenerator disks in the engine. Again, the lower exhaust temperatures (both at the rear of the car and at the exit of the engine) are fact. I know YOU never regurgitated the "asphalt melting" myth, but that's exactly what a lot of people have always associated with those cars as evidenced by the fact that it came up (within a post or two!) in this very thread. Now that a few of them are again roadworthy and making appearances at car shows so that people can actually stand near them, maybe the myths will finally die.

They really were remarkably clever, especially in the way Chrysler leveraged their existing A-727 automatic transmission as an integral part of the turibine "power unit" assembly. The torque convertor was deleted, and the input shaft of the transmission connected to the power turbine through a reduction gear. The gas generator turbine was a separate shaft. That allowed the car to come to a complete stop yet remain "in gear" with the power turbine stopped, just like the driven turbine of a torque convertor does in a conventional automatic. The A-727 worked normally in all other respects, save for the fact that its hydraulic fluid pressure was supplied by a pump driven by the engine's gas-generator turbine, and the transmission fluid did triple duty- as the turbine engine lubricant, transmission fluid/lubricant, and power steering fluid.

Of course. Its clear you know all of the following, but for others reading the thread: The turbine engine and a contemporary gasoline engine were roughly the same overall chemical input power to mechanical output power efficiency. The piston engine shed its waste heat through a) the coolant radiator, b) the exhaust gasses, c) direct radiation from the block, and d) convection cooling of the block and oil pan, approximately in that order as far as percentage of the waste heat rejected by each mechanism. For the same output power, the turbine engine had to shed the same number of joules per second of waste heat as the piston engine, but it did so without a radiator so the exhaust also carried away that portion of its wast heat. IOW, its combustion air was also its cooling air, and the air volume moved is FAR greater than the combustion air moved by the piston engine. The amount of heat energy per second is proportional to the temperature of the gas times the volume moved, so while the temperature was much lower the volume was much higher and therefore the total amount of heat rejection out the exhaust stream for the turbine IS greater (and incidentally its approximately equal to the exhaust heat plus coolant radiator heat of the piston engine).

Reply to
Steve

Odd cos 2 strokes have been runing on low ash fully synth for 20 years. (well not the same 2 stroke for 20 years but in general)

-- Peter Hill Spamtrap reply domain as per NNTP-Posting-Host in header Can of worms - what every fisherman wants. Can of worms - what every PC owner gets!

Reply to
Peter Hill

It's not seals that need that much lube. It's rotor bearings, the incoming air is drawn though the rotor to cool it. An oil mist is used to carry oil to the needle roller bearing that the rotor runs on.

-- Peter Hill Spamtrap reply domain as per NNTP-Posting-Host in header Can of worms - what every fisherman wants. Can of worms - what every PC owner gets!

Reply to
Peter Hill

Mazda never had serious issues with the rotary in the first place; the Cosmo 110s and early RXs frequently racked up 100K+ without issue.

Non turbo RX7 lumps run to 200K, and the Renesis has been alleged to be capable of the same.

Richard

Reply to
RichardK

On the Turbo.

NSU suffered problems, but they didn't have 5 years of mucking around before launching their cars. IIRC, the first Rotary Mazda was 1967, and had suitable materials/treatments and coatings.

Richard

Reply to
RichardK

The Apex seal IS the rotor tip. If the rotor rip wore out, then so had the planetary gears and everything else that keeps the engine in place ;)

Richard

Reply to
RichardK

You don't. It delivers 23-27mpg, maybe 20 at worst, in mine, for exceptional smoothness and more power than my equivalently thirsty Subaru 2.5 flat four.

Richard

Reply to
RichardK

More to the point; the oil consumption has bugger all to do with the sealing; the Renesis uses oil because it is injected into the engine to lubricate the apex seals.

Richard

Reply to
RichardK

Yes, because god knows the Crossfire's chassis and brakes are as good as an RX8...

It might as well be a two stroke BECAUSE IT USES THE OIL TO LUBRICATE THE SEALS.

Mine does about half a litre every 1,000 miles - in fact, it's done

2,400 miles and I haven't used up the bottle that came with the car - but I don't use it for short trips, I let it warm up properly (don't let it sit idling), and I drive it properly, using the revs.

Richard

Reply to
RichardK

You don't know the RX8's market well, then.

A lot of them are sold as fleet cars, purely because they have four doors and seat four ;)

Richard

Reply to
RichardK

The RX8 30 years ago would be a Mazda RX3, I think ;)

It's a £20,000 coupe. Not a £50,000 supercar.

Richard

Reply to
RichardK

You'll miss the chance to get one with a warranty if you do that ;)

Highest I've seen so far is 50K, though the basic engine is a 13B and those do 200K if looked after.

Richard

Reply to
RichardK

Arguments abound. Mazda don't recommend it, but basically, it leaves less ash. Current opinion seems to be "it won't hurt it".

Richard

Reply to
RichardK

Staffbull ( snipped-for-privacy@staffbull.net) gurgled happily, sounding much like they were saying :

An old shape SLK hit with the ugly stick and built by redneck Merkins? Hmmm. Tempting...

Reply to
Adrian

I should clarify that, it doesn't make sense. What I mean is that the oil consumption is not because the engine is poorly made or sealed, but because it is used for a specific purpose of lubricating a seal.

VW 2.0 8v engine oil consumption = bad oil consumption. Renesis oil consumption = good oil consumption :D

Richard

Reply to
RichardK

No more castor oil? I love the smell of burned castor oil...

--scott

Reply to
Scott Dorsey

In message , RichardK writes

At least you can be confident that the oil has been changed regularly...

Reply to
Steve Walker

Thank you - that was my point. Or tip, or apex...

Reply to
Ian Dalziel

I have it second hand from an RX8 driver that the Apex seals have gone on his at about 60k. Will check back to see if I heard him right.

Reply to
Tim S Kemp

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