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is it true the average life-span of the rx-8 is only about 70,000-80,000 miles?

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is it true the average life-span of the rx-8 is only about 70,000-80,000 miles?

Old 10-28-2012, 12:22 PM
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I gone thru maybe 6 set of spark plugs, 4 of them.came.from warranty

Coils 4-5 sets as well, cuz i feel like it, 3 of them from warranty, u cant beat lifetime warranty heh

.original engine died at 48k miles, low compression, but i have been having this.stalling problem for more than 20k so i think it has something to do with the ultra low omp and injector placement

I have been.premixing on new engine since day 1. Im gonna run a compression test on it this thursday cuz yep i have the mazda tool. And will report back the results
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Old 10-28-2012, 06:10 PM
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Hey guys im new to the forum and a little lost on where to post. Ive had my rx8 for over 2 years now and its been awsome until this week. Started misfiring a couple of times now its constant. Engine light came on so had it checked, came back as 'random misfire'. Occasionaly runs perfect and starts up every single time, hot or cold. Could a dirty MAF be my problem?
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Old 10-28-2012, 06:18 PM
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Old 10-28-2012, 06:45 PM
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Thanks RIWWP. Had a look there, im going to give it a shot before spending money i might not need to spend. Fingers crossed lol
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Old 10-28-2012, 11:05 PM
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Originally Posted by Jamiebhoy1984 View Post
Hey guys im new to the forum and a little lost on where to post. Ive had my rx8 for over 2 years now and its been awsome until this week. Started misfiring a couple of times now its constant. Engine light came on so had it checked, came back as 'random misfire'. Occasionaly runs perfect and starts up every single time, hot or cold. Could a dirty MAF be my problem?
coils & plugs.
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Old 10-29-2012, 05:17 AM
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Yeah thats my next option RR, although the plugs were changed just a few months ago at a service. Ill try cleaning this MAF sensor first then buy some new coils if it doesnt sort the problem. Thanks
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Old 10-29-2012, 07:01 PM
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Just buy the coils right from now and throw in some spark plug wires to complete the ignition system package. The sooner you replace those parts, the less damage you're going to cause to your engine and catalytic convertor from all the misfiring.

But, its up to you.
Either listen to us, the voice of experience with the RX-8, or you can wait, and wind up having to do what we say anyway.

BC.
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Old 11-07-2012, 12:35 AM
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people say the same thing about RX-7's that they are unreliable and break down, and i know you RX-8 guys get the same people who are misinformed ... i know plenty of RX-7's that have made it up to 200k ... im looking at picking up a RX-8 in the next few months and my mazda dealer is telling me "you dont want that car , the engine blows around 30-40k..." ... i smirked and said yes i do want an RX8
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Old 03-10-2013, 06:19 AM
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Originally Posted by Bladecutter View Post
Honestly, the answer to your question is both true and false, that Mazda's poor design in some areas can lead to the early demise of the engine in an RX-8.

The ignition coils are probably the car's weakest point, and has the greatest potential for leaving you with a dead engine. Mazda is now on their 4th version of the ignition coils.
<truncated>
Hello

my RX-8 is 2006 make and after about 50.000 miles had its engine replaced in 2010 by its first owner. Now at about 75.000 miles, the engine runs quite fine but in high rpms it sometimes makes explosion sound in exhaust. The possible causes might be

1- The coils (I don't know if they are replaced so far)
2- Spark Plug cables (Don't know if replaced so far)
3- Spark Plugs (They were replaced at about 55.000 miles)
4- The exhaust system whose catalytic converter is removed

Nowadays, I was considering replacing the coils and spark plugs and cables to see if it fixes that explosion sound in high revs.

But I didn't know that coils had 4th version. How do I know which version of coil fits the best on my engine? Thanks.
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Old 03-10-2013, 06:21 AM
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82k with perfect compression here
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Old 04-21-2014, 03:37 AM
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I sold mine at 160,000 km, and it was running fine. Also, I didn't thrash it.
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Old 04-21-2014, 11:40 AM
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Originally Posted by Lvis View Post
82k with perfect compression here
I would bet anything I have that you do not have "perfect compression" on an 82k engine. "Perfect compression" would imply "still at new spec" or in the high 8's/low 9's/125-130psi range. You may still have "levels of compression just above the lowest acceptable specification for a normally operating engine".
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Old 04-22-2014, 02:37 AM
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Originally Posted by RotaryResurrection View Post
I would bet anything I have that you do not have "perfect compression" on an 82k engine. "Perfect compression" would imply "still at new spec" or in the high 8's/low 9's/125-130psi range. You may still have "levels of compression just above the lowest acceptable specification for a normally operating engine".
I expect you're right. That was one of the reasons I sold the car at 160,000km. Low compression could result in starting problems. I had experienced these, though a couple of new coils, and spark plugs seemed to fix it.
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Old 04-24-2014, 07:23 PM
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just hit 85k and still running (knock on wood) with no problems.
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Old 04-25-2014, 01:03 AM
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2003 model on original engine 130 000km (80k Miles). Supercharged for almost 3 years with 30 000km (18k miles). I have to keep an eye on the temps at the track due to the supercharger as it can overheat when I really push the car to extremes. Well over 50 track days over a 7 year period.

Still going strong however compression is slightly lower than ideal. The biggest issue at the moment is the e shaft oil leak. I will ride it out until I rebuild. The rebuild will also allow me to upgrade the cooling system.
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Old 04-25-2014, 10:47 AM
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Honestly, if you take care of your engine it'll last a very long time. Otherwise, I don't think that would be the primary engine for helicopters... Just sayin'. Also I'm currently at 73k (though it probably had a new engine during first recall for the 04 models) and it runs great still.

I'd probably say compression and wear on the apex seals are the main things to worry about.

I'm not an expert. That is just what I've seen/heard.
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Old 04-25-2014, 10:48 AM
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And clear coat issues. But that's paint.
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Old 04-25-2014, 11:21 AM
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Originally Posted by Tailicus View Post
Honestly, if you take care of your engine it'll last a very long time. Otherwise, I don't think that would be the primary engine for helicopters... Just sayin'. Also I'm currently at 73k (though it probably had a new engine during first recall for the 04 models) and it runs great still.

I'd probably say compression and wear on the apex seals are the main things to worry about.

I'm not an expert. That is just what I've seen/heard.
Yeah, no offense but I don't think you know what you're talking about.
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Old 04-25-2014, 11:31 AM
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So, you didn't offer any thoughts. What are things to worry about with this engine? In your opinion.
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Old 04-25-2014, 11:42 AM
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RR has his opinion posted quite a few times around the forums. He rebuilds engines for a living after all.

In this case, he was simply pointing out that Tailicus's comments are largely inaccurate, from the helicopter comment (flatly untrue), to referring to the warranty as a recall (there was no recall), to "compression and wear on the apex seals" (which doesn't even make sense when you understand how everything works together).

Last edited by RIWWP; 04-25-2014 at 11:45 AM.
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Old 04-25-2014, 12:11 PM
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Originally Posted by ajrrx8 View Post
So, you didn't offer any thoughts. What are things to worry about with this engine? In your opinion.
Uhm, look up.
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Old 04-25-2014, 12:12 PM
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Two years later and this still holds true in my experience. I am now doing one rx8 every week or 2 at this point.

Originally Posted by RotaryResurrection View Post
It is my experience and observation that 80-100k is about the life expectancy of an all original rx8 engine, unless exceptional circumstances occur to push the failure sooner or later. For example, routine coolant flushes, dedicated use of premix and heavier weight oil might allow an original engine to go 120-160k, while being overly babied/carboned up with poor oil change habits and no maintenance could cause issues as early as 30k miles.

And yes, older rotaries used different placement and numbers of oil injectors.

85 and older engines used a mechanically actuated OMP with 4 lines and 4 injectors, 1 per rotor housing in the center and 2 in the primary intake runners.

86-88 engines used a mechanically actuated OMP with 4 lines and 4 injectors, 1 per rotor housing in the center and 2 in the primary intake runners.

89-91 engines used the same setup except with an electronically controlled OMP.

93-95 engines used the same type of OMP but now only 2 lines/injectors, 1 per rotor housing in the center.

04-08 rx8s used an e-omp with 4 lines and 4 injectors with injectors at the corners of the rotor housings.

09+ rx8s added an extra set of lines and injectors to the center of the rotor housings (3 per housing).

Notice that with each change, longevity of the engine seemed to be reduced. I don't think it's a stretch of the imagination to think that this is because of reduced lubrication via the OMP.

The 1st gen rx7s could last 200k or more routinely. They were notorious for burning a ton of oil, the OMP was set to inject a lot of oil so the seals got lubricated well.

The early 2nd gens were almost as good, but average longevity did drop 25-50k miles vs the 1st gens.

The later 2nd gens introduced the electronic OMP in an attempt to more closely meter the oil and reduce emissions...in other words they turned the OMP injection rate down. And guess what? Longevity dropped another 25k miles or more.

Then you have the FD. They came out with a "special" coating on the rotor housing chrome surface that they thought would reduce the need for OMP injection. So this is why they only did 2 oil lines and injectors. But, the coating must not have been as good as they anticipated, because those engines wear out at 75-90k on average. Of course, these are boosted engines that were set up to run 12psi and then detuned to 10psi and sold that way, so they ran near the edge all of the time...not all of the engine's premature death issues are OMP related.

Then the rx8 comes out, and they go back to 4 injectors. So you're saying to yourself...why don't the rx8s last longer than the older engines, if they have 4 injectors? A few reasons, in my opinion:

1) although there are 4 lines and 4 injectors, the e-omp and pcm are still in control of the VOLUME of oil that flows out. And to meet emissions they had to turn the OMP injection rate way down. You can have all the lines and injectors in the world and they won't do you any good if a minimal amount of oil is allowed to flow through them.

2) the position of the injectors in the corners of the housings prevents oil from penetrating to the center of the housing and seal...and so the center tends to wear more than the edges. Every set of apex seals I take out of rx8 engines is worn in the center and tall on the edges.

3) the chrome layer on the rx8 rotor housings is significantly thinner than what was on some of the older housings, since there is less chrome thickness it tends to groove and flake more easily, so the rotor housings are in rougher shape at lower mileages. Most of the engines I tear down with more than 100k miles are not in good enough condition to reuse and still build a nice engine.

Even if apex seal wear and weak compression do not cause the engine to become difficult to hot restart and idle without stalling, the coolant seals don't seem to last much beyond 100-125k miles as far as I can tell.

Bottom line, if you own one of these cars, here is what I'd plan on:

-ignition coils and plugs every 50k miles

-cat converter 100-125k miles

-engine rebuild/replacement 80-100k miles

And if you make it past those values on the original parts then you've done well.
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Old 04-25-2014, 06:04 PM
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RR. Guilty as charged. Should have read the thread. My question was sincere though because I know you are an engine builder. Thanks for all the info. I have an 06, I bought in 08, has 40000 miles. ( BHR coils, BHR hi flow cat w/res). Great car. Thanks
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Old 04-25-2014, 06:20 PM
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the 80k is an average number, most engines make it to 60k with no problem, some rare cases they crap out at 30k or less and almost as rare are the cars that make it to 150k+ miles on a single engine.

on average though most engines start failing compression in the 70-80k mile range when taking the above into account. those numbers are also based on the series 1 engines, not the series 2 and later.

of the engines i've torn down, at about 80k miles the rotor housings are showing excessive signs of wear due to the inferior chroming process on the renesis housings. this usually ties to exactly how you drive your car and maintain it, if you push off oil changes and rev the engine hard regularly then the life is cut more dramatically. if you drive the car reasonably and do regular maintenance including decarbs it will last you a fair bit longer. basically if you track or autocross the car it likely won't get you above that average figure.


the RX7 engines are completely different, signs of compression loss come slower so the engines last longer. for the most part the 7's had lower lifespans due to the turbo engines failing due to other reasons(fuel system issues or poorly thought out modifications to increase power) which brought their average lifespans down but they still were higher than the series 1 renesis(FB 12a- 200k+, FC 13b n/a- 165k, turboII- 125k, FD twin turbo-100k). it's not uncommon to see a non turbo RX7 going well beyond 200k miles on a single engine. in addition an RX7 can still limp around with compression figures in the 60psi range where an RX8 will begin having flooding issues at 85psi and below on the engine, factory failing spec for the renesis is [email protected](which is still fairly healthy for most RX7 engines).

those figures come from the 300 or so RX7s i've rebuilt over the last decade. the lifespans have been dropping lately due to the age of the cars, since the early engines had iron fatigue failures in addition to the rest of the common problems.

i'd still say even the twin turbo FD-REW has a higher average lifespan than the early 13B-MSP, yet it made more power and was much more easy to make a bit more power from. the 13B-MSP 6 port was the highest power naturally aspirated rotary mazda produced but it also had a cost tied to it.

the RX7s got a poor name from their owners, not from the engines which could have quite decent lifetime usage. i've seen plenty of RX7s come in that were hacked up and taped together that an RX8 would never tolerate under the hood, the engines would overheat and wind up in the shop within days.

though my thought process is the reverse of RR's in respect to renesis wear patterns. the housings i pull out are worn the most at the edges down to the steel liner and less worn in the center. ALL rotary engines have followed this path of wear for as long as i can remember where the seals crown at the edges. being taller at the ends of the seals means the housing is wearing faster than the seal at the extremeties and in the center of the seal the seal wears faster than the housings. in the RX7s there was also a wear path that followed the OMP track and it is also the same in the renesis, this additional wear IMO is caused by carbon/metal laden oil from the crankcase. i don't necessarily believe the oil injection is inadequate in volume but just in the fact that it uses dirty oil that was never meant to be used as a combustion lubricant and just a bandaid for owners who would not premix to sell cars to the general car owner.

premixing the fuel with 2 stroke oil aided the wear characteristics of the early engines, i have not tested it long term in the renesis though.

that said, most of the '04 RX8s you see for sale are for sale for a reason.

Last edited by Karack; 04-25-2014 at 06:58 PM.
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Old 04-26-2014, 11:05 AM
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Well first off I'm pretty sure Rolls Royce would argue with helicopters not using rotary engines (not the 16B obviously) seeming as how they supply a lot of them. And they were primarily used in planes first.

there have been cases where the apex seals did not efficiently touch the housing which meant it did not 'seal' properly. Perhaps it was on the housing instead, if so I apologize for confusion.

compression was supposed to be completely separate from that.

and the bottom of my hood (if I can post a picture) has a sticker that the recall (or whatever it is) took place.
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