RX7 engine life and rebuild costs ?

FOAF has recently (two weeks ago) bought himself an RX7 - fairly recent curvy sort, but with some mileage on it. Anyway, the obvious has happened - it died on the road and came home on a low-loader, suffering from sick rotor seals.

1) I thought they'd stopped doing that years ago ? Do they last a reasonable time now, or are they still dodgy with any mileage on them ? How much can you expect ?

2) He's getting engine rebuild costs quoted of 3 grand ! Now it's years since I had one of these in bits (my one and only), but I recall it being dead easy and a quick job. Does this sound reasonable ?

Thanks for any advice you can share on current Mazda Wankels.

Reply to
Andy Dingley
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Aussie website . Shedloads of the things are imported over there from Japan. steve the grease

Reply to
R L Driver
[ re the Mazda RX7 engine ]

recall

Dead simple, so is a Masseratti (sp?) V12, in principle!

"Any fool can replace the seals, how long they will last is another matter" - the words of an ex Mazda mechanic who used to rebuild (on average) an RX engine each week back in the 70's [1], I can't see that things will have changed that much considering the simplicity of the rotary engine...

[1] RX3 engine
Reply to
:::Jerry::::

:::Jerry:::: ( snipped-for-privacy@privacy.net) gurgled happily, sounding much like they were saying :

Apart from the subtle detail that the seals have all been completely redesigned and reengineered in materials that weren't available in the '70s...

Reply to
Adrian

they were

another

Your point being? An incorrectly installed seal is still an incorrectly installed seal, the tolerances are still the same.

Reply to
:::Jerry::::

Because of the mechanical simplicity, when pretty much anything internal=20 (like rotor tips etc) need doing. It is close to full rebuild time, and=20 that is supposed to be about every 60k miles.

=A33k sounds like the sort of money I've heard bandied about for a basic=20 standard rebuild.

The RX8 Renesis motor is supposedly longer lasting, but as most makers=20 plan for people to change their car every 3 years when they buy new, 60k=20 miles is outside the normal ownership period of the first, and maybe=20 even the second owner.

--=20 "Sorry Sir, the meatballs are Orf" The poster formerly known as Skodapilot.

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Reply to
Sleeker GT Phwoar

You know, I have the oddest sense of deja vu here...

I bet that RX7 is nice and black.

Richard

Reply to
RichardK

Your psychic gothpowers are clearly working just fine.

Reply to
Andy Dingley

Or the 80's either. Used to work in a scrappies for a while and RX7's always had dicked engines.

Reply to
Conor

Conor ( snipped-for-privacy@gmail.com) gurgled happily, sounding much like they were saying :

Sure, but at least they were lasting 50k instead of 15k by then...

Reply to
Adrian

Not at all. A Wankel rotary has few components, fewer rotating components, and simple motions for the ones that are moving. The all-machined nature of the rotors also means that they're in good balance straight from the factory, compared to a typical con rod.

A simple re-assembly is simpler than a piston engine, just because of the fewer parts. A real rebuild and blueprinting though is even easier, because there's a lot less work to do. Almost no balance work, combustion chambers that aren't touchable by mortal man, trivial port designs and even the bottom end is simple to assemble.

Putting the seals in is monkey work. Carefully trained conscientuous monkey, but there's only one useful way to put them in. Get it wrong and the engine won't die in 50k instead of 60k, it'll do it in 50.

The real difference over the years though has been a materials science question for the seal materials. That's why any RX-3 that is still around (and not rusted out) now runs as well as a new RX-7 -- AIUI, the design has barely changed and new seals are retrofittable, with massive improvements in reliability to modern levels.

For another thing, I think all recent Maseratis have been V6s or V8s. They haven't made a V12 since the mid-60s. Now a high-performance long-crankcase design of those days is a real bitch to work on: design and casting technology just wasn't up to it. So the crankcases is either heavyweight (R-R), tiny (Jaguar) or bendy (Italians). Building the bottom end of one of those engines properly requires either optics or a co-ordinate measurer, just to check that the thing is still straight as you build the fastener tensions up.

So, how long were his lasting ? For someone working on Wankels in the '70s when _none_ of them lasted, then that's hardly the best slogan to use.

Reply to
Andy Dingley

Ah. True.

Reply to
Conor

Why then 3000 quid for a re-con? I'd expect a decent re-con on a BMW 6 for that? Assuming no installation?

Reply to
Dave Plowman (News)

Yes, very much so, what makes it complicated are the extras and the tolerances required, it's just the same with a Wankel rotary - the number of parts is neither here nor there.

One of the major improvements that Mazda incorporated onto the later RX engines was electronic ignition, gone were the days of regular dwell and timing setting of the two distributors and the errors that crept in...

Reply to
:::Jerry::::

_What_ extras and tolerances ? It's no more critical than (as an example) piston/cylinder fit.

Have you actually rebuilt one ? I admit I've only done the one, but I bet it's one more than you have.

So what ? A good idea, but hardly changing the engine longevity, is it?

Reply to
Andy Dingley

Get yourself onto a Mazda RX forum, they'll be able to sort you out.

From what I've heard though, apparently the rebuild is actually quite simple - but the reason why it costs so much is because not many people have experience of rebuilding these engines as they're relatively rare. They're supposed to be rebuilt every 60K miles (or KM ?) you don't say how many miles the car had, how many miles the engine had done since the last rebuild (if).

Reply to
Johnny

Sir is comparing apples with oranges here. If we're talking about a

3rd-gen twin-turbo RX7 here then you should compare it to its peers - and on most other Japanese supercars, 3k doesn't even buy you the parts you tend to need.

That said, the quotes I'm familiar with are in the region of 3k-4k including installation, plus the engines are rebuilt, not recon engines that are built in rather larger numbers.

Welcome to the world of slightly insane Japanese grey imports.

Reply to
Timo Geusch

The Renesis may well be longer lasting as the main difference between a late model RX-7 and the RX8 is the lack of a few turbos on the latter.

Reply to
Timo Geusch

Sorry but I don't believe that you have even set eyes on one before, you seem totally clueless about even basic issues - BTW, I did my apprentership in a garage that had only just given up the Mazda dealership, in fact I think I might still have the engine test cradle they built - subsequently converted for another function (until it was later thrown out)...

later

If you knew the slightest thing about the importance of the correct ignition timing on all cylinders you would not need to ask such a stupid frigging question...

FSS you have one distributor doing one thing with one half of the engine and a second doing something different to the other half !

Reply to
:::Jerry::::

Bought cheap on fleabay, has he? One never, ever buys a rotary without having a compression test done to show up a duff engine, because they don't feel worn right up to the point where they go bang.

Around 60k seems to be the norm. The late model, curvy (non-Porsche 944 shaped) twin-turbo seems to last for anything between 30k and 100k, depending on the modifications and how heavy the PO's right foot was.

Open up the bonnet and go find the engine, that's why it's around that kind of money...

The twin turbo has an insane amount of plumbing under the bonnet due to all the ancilliaries, emission gear and all the vaccuum tubing for the sequential turbos.

Actually the last time I enquired I was quoted closer to 4k for a full, proper rebuild from someone who knows exactly what he's doing. That included removal and installation of the engine, by the way.

Have a look over at

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for more help.

Reply to
Timo Geusch

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