h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

The Mazda RX-7 was first produced in 1978 not '79 as the article stated. The RX-7's history is linked to the success of the Mazda motor company.
When Felix Wankel patented the rotary engine in 1933 (he was attempting to build a supercharger for a motorcycle engine but erred) he found himself with a revoloutionary design that used trichoidal (trianglish) shaped rotars instead of pistons, this allows for the full combustion cycle to take place simultaneously as the rotar chamber (cylinder in a reciprocating engine) is divided into three sections.
many companies showed interest in the design and a plethors af companies for GM to Rolls Royce built prototypes but very few actually released a rotary powered vehicle (interestingly a leading Japanese motorcycle company released a rotary powered bike!). In the end Felix went to work with a small Japanese company that specialised in three wheeled light commercial vehicles.
The first rotary powered vehicle was the Mazda Combo but the first to be released internationally was the 1969 R100 with a twin rotar one litre engine. The rotary phenomenon exploded and at one stage looked destined to take over from the recipricating engine. Then came the 70's and the oil crisis.
Rotary's are notoriously thirsty and demand died. The rotary engine was to be forgotten and Mazda (now a large and successful company) was looking to compete with traditionally powered vehicles (which they'd produced along with the rotary versions - in fact all rotary's up to 1978 had a piston powered version). The company decided to have one last go at the marketability of the rotary engine and designed a car with just this engine in mind and that could bring out its best, without compromise. Hence the hugely successful RX-7. More successful than Mazda could have hoped, stories abound of demand being so great that Mazda would rapidly raise the price to curb demand to meet production but with little effect.
Yes more than a pretty car with pop-up headlights.

Jason,

I like your reply - very detailed although I have to make a few changes. The first rotary powered car available to the public was produced by NSU (a german company with eventual links to Audi.) It was not a success by any measure, due to many of the problems suffered by Mazda in the early years - poor cooling and apex seals. Also, I will assume that you simply made a spelling error in regards to the first Mazda rotary powered vehicle. You have "Combo" but the actual name was, "Cozmo." This name was used again in the seventies for a vehicle that could also be called the RX-5, a bloated Japanese luxo-coupe similar in appearance to the Datsun 810 coupe. This, by the way, lead to an interesting skip in the RX naming tradition - there was not an RX-6 as this nomenclature did not sound as appealing to Mazda management as, RX-7.

You might like to know that Mazda is (again) talking of producing a new version of the RX-7 and recently showed a concept version, but as with so many concepts and rumors this is unlikely to be released. (One problem that I heard of with the Wankel engine design was that the seals on the rotors wore out quite quickly with a corresponding loss in performance and efficiency.)

Premature wear of the Rotor Apex Seals has always been a problem with Rotary engines. However, Mazda has made great strides through the years to reduce this natural occurance. In other words, the problems faced by RX-3 and earlier models are almost erradicated for the latest Rotary engines. Since we are on the subject though, another issue with Rotary engines is the wear on the rotor housing (the sealed chamber in which the rotor moves through it's 4 cycles.) This chamber wears just as the cylinders in a reciprocating engine. The problem caused by this is that it is much more difficult to resurface a rotor housing. Any decent machine shop can refinish a cylinder of a piston engine but it takes special equipment and specialized skills to refinish a rotor housing. This means that Rotary engines effectively have a limited life where reciprocating engines can be remanufactured many times over. Don't get me wrong. I am not knocking (no pun intended) the rotary engine. I think it is an amazing piece of machinery and a fine sports car engine.

I have seen many of the concepts presented by Mazda including the RX-Evolve and look forward to the return of a rotary powered sports car (or sedan) to the United States.

I can't believe I missed this article for so long! For more information about RX-7s check www.Mazspeed.com.

It's Cosmo, not Cozmo or Combo

The RX-7 is still in production, they just don't ship any to the US. When the government introduced OBDII and required manufacturers to comply, Mazda didn't see any point in spending the money to update the RX-7 when they were still trying to sell the previous year's cars. Somewhat interesting seeing as a $35,000 RX-7 would kick the snot out of a $45,000 Vette or 300ZX, and keep up with a $60,000 Supra.

I recently had to replace the engine in my '83 RX-7. The original engine had 173,000 miles on it and was running strong. The engine failed due to FOD (foreign object debris). From what I can tell a chunk of carbon came loose and knocked an apex seal out of the back rotor. The apex seal severly damaged both the rotor and housing, effectively destroying them (too damaged to repair). The engine still ran, but very poorly and began smoking. The front rotor, seals, and housing look near mint; a friend is going to use them when he rebuilds his motor (somebody attempted to fix a dowel-pin oil leak improperly). The housing surface has a chrome-like finish and doesn't wear much. Apex seals are also pretty durable. The stock steel ones last very long if the engine is taken care of. Ceramic apex seals apparently NEVER wear out (but are horribly expensive). Carbon apex seals won't last much more than 50,000 miles but are great for high-rpm use.

The main reason rotary engines get knocked by people is misunderstanding. I always hear "my brother had one that seized up just over 100,000 miles". Often people neglected to change the oil, clogging up the oil tubes that feed the apex seals - deadly to a rotary. Rotaries are also bad about apex seals getting carboned up and sticking, causing a loss of compression. This is not the death of a rotary motor, it just needs an ATF treatment (see www.Mazspeed.com). RX-7s are like turbocharged cars, they are incredibly reliable AS LONG AS YOU MAINTAIN THEM! Most people don't take the time to properly maintain their vehicles.