Comment by busterarm | Hacker News Reader

Comment by busterarm | Hacker News Reader

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2nd Generation Turbo RX7 owner here. Rebuilt 13B engines before.

The reliability of the engine itself is way misunderstood. They aren't more or less reliable than any other engine (okay, they're way more reliable than Subaru engines...).

The problems are with heat and lubrication. The early RX8s had a flawed design. 2nd and 3rd Gen RX7s had problems with their OMPs and terrible electrical problems. 2nd gens have really weak alternators stock. Turbos usually fail before engines do.

Honestly the engine itself is awesome. Yes, if you lose a seal it will screw your engine (but usually the housings & rotors are salvageable). Piston engines throw rods and screw your whole car. If you bypass the OMP and run premix and actually do proper maintenance on your car, they will last. My 10AE has over 110k miles on it and has not blown up yet -- probably has another another 40k on it before it'll be ready for a rebuild. I still am on the stock OMP (it's an S4).

My 10AE has over 110k miles on it and has not blown up yet -- probably has another another 40k on it before it'll be ready for a rebuild.

That's really low. I don't think I've ever bought a car with only 110k miles on it...

in canada it is unusual to see cars with more than 300,000 km on them, so a vehicle with 176,000 km is more than half way to being really well used, not "really low" mileage.

I had a toyota land cruiser with 365,000km on rebuilt engine and 800,000 km on the body though.

Where do you live that 110k miles is low mileage? How many miles is a lot to you? How/why are people driving that much?

> in canada it is unusual to see cars with more than 300,000 km on them

That's largely because of the need to salt roads in the canadian winters - yearly, excessive exposure to salt water drastically limits the possible lifetime of a car. The further away from cold weather requiring salted roadways you get, the longer cars last.

So in developed countries that don't have icy winter roads most people are driving cars with more than 300,000 km on them?

I'm really curious where the parent lives that people are investing so much in the longevity of a vehicle. By the time they get to 300,000 km even if they aren't rusty they are usually 20 years old and things like drivetrain start to go and the vehicle is not worth the cost to keep up the required maintenance.

Certainly not most, but definitely more.

Here in Texas, where the roads are clean and we drive a lot, cars with 300,000km (or, let's say, 200,000mi which is a similar milestone) certainly exist, but are somewhat unusual. But they're not worth much and likely nearing the retirement point from sheer age.

I can attest that this is not unheard of in southern california. 1995 cars are driving all over the place. Cars seem to have a lifecycle where they get sold to poorer owners with more and more miles piling on, and only get junked when they are beyond repair. Even a 150-200k miles car is worthy of selling on craigslist (for super cheap of course, but there are plenty of buyers).

Now to be fair, SoCal has a rather unique and essential car culture, so this is probably an outlier as far as "most" cities go.

Even in developed countries people are driving their cars way over 300,000 km. Some cars are capable of over 482,803 km without major repairs needed. The Ford Crown Victoria comes to mind, the one used for police cars and taxes. I just read in a forum that police cars are used up to 643,738 km, at that point they're passed off to a taxi service for continued use. http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=show...

Not all places use salt, and even then if you get your car washed and underbody cleaned it should help the longevity of the car.

Yup. Even in snowy places -- my folks, siblings, friends all have cars running in Wisconsin that have at one point or another hit or crossed the 300,000km threshold. We had a Grand Caravan that looked pretty good when we finally traded it in at 350,000km.

Older cars, you keep them relatively clean and knock your boots before getting in so that the salt doesn't grind your carpets away, and replace things as they start to fail. A lot of older cars will just keep on chugging along.

I live in the US, have lived in the following states: CT, NY, LA, and now CO. Almost all of my parents cars have over 210k miles on them and they're still going. My car has 114k miles on it and it runs perfectly, if all goes well it should easily hit 200k and beyond. Also, the next car I buy, if it's for under $3k used, I wouldn't mind it having 140k miles if it's a reliable car.

Yeah, I really lucked into a low mileage car when I got it. Somebody had already restored it from being in bad shape before me -- saved me about 3 years of work and a lot of money.

The 10AE year was 1988...

> okay, they're way more reliable than Subaru engines...

Are Subaru engines really unreliable? I was under the impression that as long as you kept the power output under about 300 wheel horsepower that the entire drivetrain is pretty reliable.

Everything about Subarus are pretty bulletproof -- except the engine.

But you're mostly right. They will last if you leave the car 100% stock. Just don't modify them. Ever.

This book[1] on the Wankel history considered 150k miles the life expectancy for the 13B, less than for previous motors.

They're really cool motors, I'm in that boat with you. How they work means forced-induction doesn't necessarily impact engine life the same way FI on piston/crankshaft motors. That the piston motor is just going to last longer not needing or before it needs major restoration.

A mildly interesting point is that heat isn't an easily mitigated factor, unless we're talking the exact use cases in the OP article -- generators, which run in a very controlled RPM band. Same when we talk about UAV engines or other electricity-generation applications. So, you can engineer the motor to be efficient at those rotation speeds WRT heat management and fuel efficiency.

1: https://books.google.de/books?id=IB2lMFqTTl8C&pg=PA117&lpg=P...

Glad to see their longevity is improved. I had a '74 RX-4 and the conventional wisdom at the time was that you'd get 70-80k miles before you'd lose compression on one of your tip seals. My dad got 80k on the first motor so we weren't too bummed. We changed the motor for a new one and it was still going strong when the body rusted away so badly it wasn't worth fixing. Fun car, though.

IIRC, the turbo issue was the usual one around heat stress, and a turbo timer went a long way towards easing that.

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