How can you tell if an RX8 is worth taking a chance on?

The cheap RX8s with issues are exploding in volume around here lately. I've always liked them but the potential issues scared me off when they were still trading hands in the $10k range. Now, at $3k or less, not so much. My question is, how can you tell if one is worth taking a chance on? Do you just buy one, throw coils at it and hope for the best? What is the deal with them regaining compression after new coils? What would I be looking for, or is it a total roll of the dice? There are also plenty of (supposedly) great runners in the $5k range, but if I could have a well-running RX8 for $2500 and a set of coils, I'd rather go that route.

I am only a few hours' drive away from Banzai so I suppose a dead motor would be an excuse to get a rebuild and street port, but still...

Few examples:

http://chicago.craigslist.org/sox/cto/5543692611.html

http://milwaukee.craigslist.org/cto/5545194461.html

I'm very much in the same boat. In for answer.

Another example. Seems learning how to rebuild these things would be a good side gig.

http://dayton.craigslist.org/cto/5544717317.html

Ironically enough it seems like all of us posting so far are within driving distance of Banzai, who charges $1700 to do it for you. Not exactly cheap, but cheap enough to not totally lose your ass if the $2500 car needs more than coils. Would give you a $4200 RX-8 with a known good motor.

http://www.banzai-racing.com/store/rotary_engine_rebuild.html

The issue is that the S1 car's compression measurement is compromised by bad coils and a weak starter on the S1 (S2 starter is more powerful) so the compression can actually rise and the car start more easily if you replace them.

If the car doesn't start at all then it's either got a blown starter or the engine is just done.

I don't think I would buy an RX-8 that doesn't start at all or that has trouble hot starting. You're looking at an engine rebuild at that point no matter what you do.

pointofdeparture wrote: Ironically enough it seems like all of us posting so far are within driving distance of Banzai, who charges $1700 to do it for you. Not exactly cheap, but cheap enough to not totally lose your ass if the $2500 car needs more than coils. Would give you a $4200 RX-8 with a known good motor. http://www.banzai-racing.com/store/rotary_engine_rebuild.html

The thing is, you're probably not getting away with the $1700 rebuild on most of these cars. If they are losing compression to the point where they don't start or have hot start issues then you're at least doing the Level 2 rebuild if not a rotor housing.

My friend's 8 had some slow starting issues, but generally ran and started okay when they replaced coils and starter. When they went in to rebuild the motor they needed to do all seals and replace one of the rotor housings. Now you're up to the Level 4 rebuild.

Cheap RX-8s and FRs/BRZs have always seemed like ideal LS swap candidates to me

The other thing is that you're not even paying for a huge amount of labor for this rebuild it's that the parts are pretty expensive.

Well that pretty much answers that question then. I've always heard rotaries are easy to rebuild, but the cost has never really been mentioned. I didn't realize the RX8s burn through so many components!

High miles on an original engine?

If you can go into it planning that you'll spend $3k on the car, ~$4-5k on an engine and will probably never get your money out of it, go for it. Otherwise, FRS/BRZs are lighter, probably more fun in stock trim, and can be bought and sold for ~$13k :)

1uz swap. I'll be into mine about 2000$. That 250hp and 260tq. V8 awesomeness. ToyotA reliability. And the same power level as the stock engine, but with more torque.

Have been watching these for a while pricing out the options. The LS ones I've seen done are all 14K plus and have been really rough. Was heart broken at how rough a L33 swapped RX* was that I drove last week in Dallas. It was eyeball melting fast but had just too many issues for it's 13.5 asking price.

My issue with building one is that it seems like 12K plus and 6months of cars torn up in the garage. The wiring, brains, and fuel system seem to be the tough issues to address following the other standard swap mechanicals/mounts. The toyota v8 would be cheaper buy-in but all the same issues otherwise.

Wouldn't a Duratec 2.3/2.5 liter truck motor out of a Ranger be a good swap candidate? They can't be too expensive..

In reply to 84FSP:

Are you talking about all that "new fangled" can-bus? If you can't handle the bus, drop the idea.

pointofdeparture wrote: Well that pretty much answers that question then. I've always heard rotaries are easy to rebuild, but the cost has never really been mentioned. I didn't realize the RX8s burn through so many components!

It's actually not the number of components, it's the price of them. The parts are pretty low volume with corresponding prices.

In reply to Trackmouse:

Have heard about canbus as an option but know next to nothing about it. Have seen it done a few different ways. Aftermarket or GM ECU for the LS and factory mazda for everything else. It does scare me and I have 3k baked into to the 12k price to cover that portion of the pain and suffering. Will learn by helping and watching but not comfy to take it on myself.

if it's had a ls swap

(trolling)

FYI the wiring on the 1uz is simple. Very simple. All self contained. All you need is to intercept the known wires to power the fuel pump, check engine light, and the ignition positions. That's really it. Of course those need relays, but you was gonna add them anyways.

Well, the whole idea of a $2500 RX8 was to make it work easily and cheaply as-is, if that was possible. Since that's not really the case (at least unless you get really lucky), there are much better swap recipients IMO; ones that don't need to pass OBD2 emissions, which the RX8 would have to in my neck of the woods regardless of what's under the hood.

I had no idea these were so cheap. There is one near me for $950, in need of a head gasket.

Probably left the factory that way.

Mike wrote: I had no idea these were so cheap. There is one near me for $950, in need of a head gasket. Probably left the factory that way.

Inversely, I've seen a handful of ads for RX7s and RX8s over the years that claimed a recent timing belt replacement.

I bought an rx8 for 2300 and sold it for 5200. I replaced coils and plugs to fix a non start issue. Was really a flooding issue. I had to replace the starter to fix a hot start issue. Part of the issue is the oil metering pump getting plugged up causing premature apex seal failure. If I had been keeping it I would have done a Sohn valve replacement to feed 2 stroke oil into the combustion chamber and added a small amount of 2 stroke oil to the gas. The Wankel engines are still technically 4 stroke engines, but are oiled in the combustion chamber.

A large number of rx-8 engines were replaced due to failed coils and plugs. The plug fires 3 times per rotation to make a 2 rotor engine perform like a v6. On your standard v6 coils last 90,000 miles, on a rotary, 30,000 is pretty good.

The only proper way to diagnosis things is to get a compression test at a Mazda dealership with a rotary compression tester.

Are you willing to put money into that you may not get back?

That's really the question.