Cars with bad reps, fair & justified or unfair myths

The 'tip wear' on rotary engines is itself one of those myths, and one wrapped in several lyres of misunderstanding and pub hearsay.

Firstly, the tips of the rotors themselves do not wear, but the 'apex seal' (that could be considered equivalent to a piston ring as it seals the tips to the housing) does.

There was an issue with apex seal wear in the 60s and 70s, but a switch from carbon seals to steel that went along with improvements in the hard chromed surface of the aluminium rotor housing essentially stopped that problem before those first rx7s were made. In fact with that generation of 12a engines its much more likely to have compression loss due to the chrome surface of the housing flaking off. When I was involved with 1st gen Rx7s, about 10 years ago, I would say most cars were on their original un-opened 12a engines, many running the best part of 100,000 miles. It was often an overall 'wearing out' that stopped these 12a engines, as they were in a fairly low state of tune making just 115hp n/a.

It's only really minimal internal changes, along with 10mm wider rotors to increase capacity from 1200-1300cc, between this n/a 12a and the 13b engine at the core of the twin turbo Fd Rx7 making 300hp. Once there's the high temperatures and pressures that go along with the higher state of tune, then the engine becomes more fragile. And yes, when turbo'd then detonation can cause the apex seals to chip or break causing catastrophic loss of compression and major engine damage.

It should also be pointed out there are 3 sets of 'hard seals' in a rotary engine that work together to replace the piston rings in a normal engine. The apex seals, which everyone has heard of, but also side seals and corner seals (that go at the corners where the apex and side seals meet). All 3 sets of seals can wear over time, and in fact in the Rx8s it's more often than not the side seals that are the culprit for low compression as with the repositioned exhaust port they get jammed with carbon.

I'm not entirely defending the rotary engine, the fuel economy was poor (when comparing to other similar power engines) and they are more susceptible to issues caused by poor maintenance and from damage to water seals caused by overheating than the average piston engine. And as mentioned above as you raise the power levels they do become increasingly fragile.

Still I enjoyed mine very much when I had my Rx7 and rotary engined Mx5.

When I bought my Elan all the "experts" said don't worry about the Ford gearbox and diff it's the Lotus engine which will give you all the trouble, 25 years later both the gearbox and diff have expired but the engine has needed nothing but servicing.

The key to successful ownership of an Alfa:

Buy a shiny red one.
Have the recovery driver unload it where you can see it.
Polish the hell out of it.
Throw the key away.

Then, in six years time when your wife says 'either the eyesore goes, or I do' you won't have had too much pain and expense