new rotary engine trouble ?

Johannes ( snipped-for-privacy@stop-spam-sizefitter.com) gurgled happily, sounding much like they were saying :

Ah, of course. The Trevi. Another utterly forgotten Lancia...

Yes its true, although not for the RX-8 AFAIK. The '7 manual specifies mineral oil only. I think Mazda were worried about the effect that burning some of the additives in synthetic would have on the apex seals. Seem to have got over that in the '8. Some folk have used synthetic in 7s without any problems (short term at least). IMO best to stick with what Mazda says as they're the experts on these things.

Nope, I saw it leave out the back after any heavy engine braking...

Hated leaving a cloud of crap behind, so I sold it on to the other side of the country ;-)

Curiously it only got bad when the oil got a bit low - for a week or so after topping up I never saw a drop.

(Still passed two MOTs though!)

Oh I see! I assumed he was talking about Beta bodywork...

Beta hatch.

Ummm... other than sucking fuel like a big-block V8, the RX-7 engine was as reliable as a brick back in the 1980s. As mileage pushed 200k they would still get tip seal flutter and some consequent power loss, but they were basically as reliable as any piston engine. The real problems were with the first couple of generations of the engine in the 1970s. I'd expect the RX-8 engine to be very good. I'm not a huge Mazda fan in general, but the rotary engine isn't an inherent nightmare and hasn't been for 30 years. But it still is a bit of a fuel drinker and doesn't have much low-RPM punch according to friends who've had RX-8s for a couple of years now.

Very true... And they've been DRASTICALLY reduced since the mid 70s. There is still some DELIBERATE oil consumption (metered into the tip seals and lost after lubricating them) and high fuel consumption is a byproduct of the fact that the combustion chamber is, in effect, moving from a cold region where the fuel is introduced toward a hot region where combustion actually occurs. But that too isn't nearly as bad as it was when rotary engines were carbureted and liquid fuel would go swishing around the chamber and out the tailpipe when they were cold.

Yes, but the are seals that ride in grooves machined into the rotor tip. The rotor tip itself doesn't touch the chamber wall. According to a co-worker who's a rotary afficianado, the rotor grooves that the seals float in DO wear. But no faster than cylinder walls or piston ring grooves wear in a conventional engine. IOW, its not an issue that makes the life of a rotary inherently shorter than the life of a reciprocator.

And the new Mustang GT is slower than a 1970 Mach 1, so what's the point? The new Charger is slower than a '69 Hemi Charger R/T, so what's the point?

:-p

Give *me* the old Mach 1 or Charger (screw the Lotus) any day... but there are a lot of folks out there that like the refinements and creature comforts that come with the modern cars. Personal preferences aside, the RX-8 is a wonderful, smooth, powerful, user-friendly little sports/commuter car in a package that can even double as a second family car if it has to. Try THAT with a Lotus...

Another myth. The Chrysler Turbine Car's exhaust gas temperature was/is several HUNDRED degrees lower than a piston engine's exhaust gas temperature. And that is with 1962 technology.

Lots of tech info here, but be aware that you'll hear a sound file of a Chrysler Turbine starting and idling when the page loads, so have your sound turned down if you don't want to disturb coworkers:

ROTFL!

You sure its not flop-bott or felon? She maght go wrang in 'er ewer, tha knows.

People just don't GET it. A metered amount of oil is DELIBERATELY consumed in rotary engines. If that is enough to make you refuse to own it, fine. But its not a "defect."

: Ian Johnston wrote: : : > On Sat, 25 Mar 2006 21:29:54 UTC, Conor : > wrote: : > : > : In article , Chas Hurst : > : says... : > : : > : > The apex seal problem was solved in the early 70's. I never heard of rotor : > : > tip wear. : > : > : > : Came across alot of it when I did a stint in a scrappies. : > : > Stagnation o't lung. : : ROTFL! : : You sure its not flop-bott or felon? She maght go wrang in 'er ewer, tha : knows.

Bloody masticks. But it could be worm in't tail.

Ian

Then why is it that in the tech papers Chrysler put out they stated plainly that one of the problems was the EGT was very high and that alloys that could handle those temperatures were too expensive to make production feasible.

Some of the tech papers are ON that site that I referenced, and they DON'T say that EGT was high, they say that ITT was high under certain abnormal conditions.

"Inlet Turbine Temperature" is not the same as "Exhaust Gas Temperature," and the turbine inlet temperatures really only spiked too high during an incorrect start procedure that was corrected via interlocks that prevented the driver from putting the car in gear before the turbine start process was complete. The materials issues were more to do with the regenrator disks that had to operate at very high temperatures because they were a key component in REDUCING the exhaust gas temperature.

Indeed but as there are no thermocouples positioned at the first stage turbine inlet (they would melt), this will be a temperature calculated from the EGT thermocouples further back. Its only in the past 20 years or so that engines have been able to measure turbine temperature a lot further forward using optical pyrometers etc.

Why the frack don't people go and READ the papers before making ASSumptions?

Regardless of the instrumentation, it was clear that ITT was spiking too high when diagnosing damaged parts from the engines that developed problems without the start procedure interlock. NONE of the cars were fully instrumented- this was the fleet of cars that was put out in the hands of the public for an extended test, not an instrumented test mule. They did have an in-dash ITT gauge, but whether it was direct measurement or derived from an EGT measurement I do not know.

But one fact that WAS clearly measured WITH instrumentation ws that the EGT was over 400 degrees LOWER than the EGT of a piston engine under similar operating conditions. No "melting asphalt at stoplights," no "second degree burns to pedestrians walking behind the car" or any of the other lame-brained myths that have sprung up in the 40+ years since the cars were built. END OF STORY!!!

I made no ASSumptions. I based my comments on 30 years working on Gas Turbine engines.

But I do know. It wouldn't have been direct reading..... believe me.

I never suggested that this engine would melt tarmac or burn pedestrians. As an aside though, although the EGT of a piston engine may be higher as it leaves the cylinder head, in a typical car installation with its long exhaust pipe, the gasses leaving the exhaust will be cooler than a small gas turbine with its shorter jet pipe. The other thing to consider is that its not just a case of temperature. The Gas Turbine will be producing greater quantities of hot gas than the piston engine.

The message from Paul Giverin contains these words:

Which is why I mentioned blowing tailgaters away.