Tbo
 

In another thread, someone mentioned that the expected life of a Mazda rotary was 200K miles.

With aircraft engines, there is the concept of 'Time Between Overhauls', and you have to budget it into your operational expenses. Let's say you buy a Cessna/Piper/Beech with a Lycoming or Continental engine that has nearly 0 hours Since Major Overhaul (SMOH). Let's say the TBO on that engine is 2000 hours, and it will cost $15,000 to rebuild it. You should be putting away about $8/running hour in an account so that when you reach TBO, you have enough in the kitty to pay for the rebuild/replacement of the engine. This of course is in addition to routine maintenance, shit happening, and the many other complex, expensive parts of the aircraft.

Applying this concept to the RX-8, if the accepted TBO on the engine is 200K miles, how much will the rebuild cost at that time? What's involved - just cleaning accumulated scuzz off the rotor faces and replacing the apex seals, or resurfacing/replacing the entire combustion chamber and output shaft? This is assuming 'normal' driving, not thrashing it.

The M20B27 engine in my old BMW 528e had 212,000 on it when I sold it, and would probably have happily done 300,000+ (I read rumours of 500,000mile+ engines in those cars, selling it for the VW was one of the stupider things I've ever done). My current VW VR6 engine has 136,000 and I feel confident that it would probably reach 250,000 with no sweat, but the rest of the car (including the THIRD a/c compressor now) will have shat itself long before then. I really want my next car to be as long-term durable as the old mid-80s BMWs and Mercedes' were, but there seem to be very few, if any, cars with that much solidity any more.

Put away $0.50 a mile and get a Viper instead of rebuilding your '8. ;)

(Sorry, I couldn't resist.)

I mentioned the lifespan of the average 2nd gen Rx7 NA engine was 200,000 - both 2nd gens I owned were from previous owners, so there is no telling how the cars were treated, but at the time either a rebuild on an engine or a rebuilt engine was only about 3000 so that would give you about $.015 per mile... not too bad. I would expect with the better apex seal technology (the culprit for the rebuilds in 2nd gens) the renesis should last longer than that if kept up properly. BTW a rebuild is usually due to a blown apex seal and consists of cleaning things up a bit, and replacing all the seals, but thats about all that can go wrong with these engines, no rods, valves, crankshafts, camshafts, timing chains, etc... so just from the law of entropy we should be able to outlast the typical piston engine since there are fewer essential things that want to move towards disorder.