burning smell
 

Burning smell that is getting stranger...1400 kms since rebuild.
ive ruled out...
no leaks or not enough from rear eccentric shaft.
no other leaks
cat is not on fire .
i didn't run over a plastic bag
engine has been steam cleaned. No oil spilled anywhere....tried with a new cabin filter...and without a cabin filter
so here's the problem. ..
when i turn down the temperature as low as it will go without turning on the ac and on fresh air ..i get a slight burning plastic smell through the vents...
However. .i tried an experiment today..
it doesn't happen on recirculation. .
it also doesn't happen on fresh air but with the heating on...
is the heater core starting to melt something around it...only happens after a prolonged drive..thr car has been run and examined underneath when.hot..
anyone experiencenced this.

Just bought an 05. I notice a distinct rubber smell coming from the engine when I first start it up. While driving and coming to a stop I occasionally get a wif of the same smell. The only thing I can figure is maybe the belts.

If your belts are that loose, you will be able to tell by pressing your finger on the belts. They normally shouldn't have a lot of play.

dalippy: check for oil leaks at the OMP to engine block joint. They're almost invisible but end up flinging oil onto the exhaust manifold at speed. Best seen from underneath.

I don't think it would be the heater core, it doesn't get hotter than coolant, and that's around water boiling temp, not enough to melt anything.

If it doesn't happen on recirc, then the smell is from outside I recon.

Anything sitting close to the exhaust manifold? Loose wires maybe?

@petscar: when you first start it up, everything is cold, so whatever you're smelling would have to come from the exhaust gases. How is your coolabc level?

Did you mean coolant level? If you did, I haven't but I will. It should be ok because the guy I bought it for just had it serviced at Mazda in April. Is there a reason you suggest checking the coolant?

Because if you have coolant seeping into the combustion chamber, the exhaust will smell sweet on start up. Depending on your sense of smell, that may be what you're sensing.

I will definitely check that. But wouldn't you smell that at the back of the car? Mine is from the engine compartment.

re
 

Just an update thanks for the suggestions..no the belts are not loose..and I've another thread about omp pumps...had some trouble. .it is now perfect
.
its just good old fashioned engine fumes. .The heat here got a bit much this summer 30.c or 90.f in old money. .wasn't helping
i bought an activated carbon cabin filter..
mazda are very expensive. ..here in Europe mazda use mahle for filters..so got a mahle carbon filter ...
problem solved. .
​​​​​​​because there is absolutely nothing else it could be

@ pets car..put it on a ramp and check absolutely everywhere for leaks before you do anything else. ..don't miss the front oil cooler. .they can leak too.
I've a funny feeling that intake manifold is blowing out some fumes of the engine ..that oil that collects before the maf intake pipe is a quirk of that engine. .the rotors throw droplets of oil up through the intake.. (all the engines are like this I've seen loads..its not inconceivable that gas is escsping through a slightly aged o ring in the same spot..considering the odd foibles of these engines as regards heat transfer and half the raw fuel being spat out the exhaust port i wouldn't be surprised

Thanks.

The rotors are not throwing oil up the intake against transsonic airflow. That oil is forced into the intake via the PCV by excess blowby pressure. If all the ones you've seen are like this, then they're all broken. A healthy car's intake is bone dry.

Nor is half the fuel spat out the exhaust, the cars run near stoich AFR just like any engine. On a healthy engine, obviously.

...its all over this website about the oil sitting in the air intake. .
I've seen a mazda workshop bulletin about the fact if cars come in experiencing this problem its a normal quirk of the engine. ..not a symptom of a worn engine..
...blow by ?what the f##k are you talking about its not a piston engine...
and you are talking through your ass about not spitting half burned fuel...
why is there a leading and trailing spark plug..
it was an unsuccessful attempt by mazda to burn all the fuel ...
spitting flames out exhaust?
cats going on fire...
19 mpg
i could go on but i couldn't be bothered
thanks for trying to help but you haven't a clue..
ill give you some marks for effort but try to stop talking through your ass..it exposes your ignorance

Lol. Ok.

You tried. He'll figure it out eventually.

https://cimg1.ibsrv.net/gimg/www.rx8...1bb1213801.png
​​​​​​​keyboard warriors.../armchair mechanics
nothing constructive to add...
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Ok, one last shot to help get you in the right direction.

1) If you are feeling much at all come through the breather, that's a problem. On both of my engines, even with the one that was failing, there was no flow (more on this later). I never experienced oil in the intake either.
2) My engine failed on one of the rotors with 2 weak pulses, one strong pulse. What does this mean? Apex seal damage. Compression bleeding from one side of the rotor to the other.
3) We've also seen plenty of example of 1 weak pulse, 2 strong pulses. What does this mean? That means there's either a side seal failure or a corner seal failure. Compression is bleeding through the side/corners seals.

Which...brings me to my point. Where does that compressed air go when it is bleeding around the side/corner seals?

It has to go somewhere.....and that's out the PCV. It goes around the side/corner seals, around the oil control rings...into the crankcase raising the pressure. That pressure is bled off through the PCV tube, right back into the intake. Because that air is traveling through the crankcase, it takes oil/oil mist with it...which is why you find oil in the intake accordion. As of note, its also possible to get oil in the intake by simply overfilling. What you are describing though is air flow out the PCV, which simply shouldn't be there to the level you are describing.

Like Loki was saying, oil doesn't come back up through the jet air nozzles and back into the intake. That is high velocity air with a large pressure delta...all the air/oil is traveling INTO the engine at high velocity.

Now, unless I've never seen it, there's not an allowable PCV flow spec called out in the factory service manual. The way to find out for sure is compression test, which Mazda references many times. That'll give you an overall health report on your engine. And from the pulse patterns, can see what is wrong. Apex seal, side seal, or just generally worn out.

In summary: Get a compression test.

thanks for the info...yeah more constructive
but the car was checked pre rebuild for compression ..it was very low...i can't remember what it was. ..its on another thread i left
but the engine has been rebuilt and compression tested pre and post break in period and is showing very healthy numbers. ..
and as regards the oil in the intake. .its not much. ..
and i really was shown two workshop bulletins direct from mazda...i took a picture of the bulletins ..if i find it ill post it...
but 1st bulletin was that mazda recommend now...After research using mineral oil instead of synthetic. .because of its ability to burn cleaner and not stick to the ports/walls of rotor housing. . (Synthetic /semi doesn't burn well. ..causing gumming of the ports and or rotor tips...
This in turn extends rotor tip and or housing life..
The bulletin came from Japan with pictures of research
The 2nd bulletin may be related to the first. .causing unexpected 'blow by'
but basically as i said before mazdas outlook on a little oil in the intake is "don't worry about it ..its normal ". .im not talking about a litre. Only a thimble amount...
now if you want to disagree with me and tell me im lying. ..or just plain old wrong. .thats fine im not really too bothered im not gaining much from this site...all my problems I've had so far have been solved by professional rotary engine builder's and talking to mazda trained mechanics.
i understand what you are saying. ..oil can push past worn side seals ,rotor tips and oil rings...resulting in a worn engine pushing oil out in a nutshell. ..
but my engine isn't worn...and some oil in the intake is normal. .
don't forget im in Europe here and the specs are slightly different here
..we have little or no autos and a lot of 190 manuals. .all our cars come with lsds etc..so the specs are not the same. ..the fan housing isn't even on the same side

I wouldn't too concerned about the very small amount of oil. For all I care, I could have just overfilled a small amount anyway.

As for synthetic versus conventional, some members here use synthetic and seem to do just fine. I use conventional, but mainly because at 3000 mile/5000 km interval, any advantage of synthetic oil goes out of the window. If you use a SOHN adapter and inject 2-stroke into your engine, then using synthetic is fine since it's no longer being burnt.

full synthetic is a no no
no one that has anything to do with mazda recommends it even with the sohn adapter a certain amount of residual oil will still be burned
...engine class 1st day...synthetic oil doesn't burn well

but maybe guys fiddling in their sheds know be
 

https://cimg1.ibsrv.net/gimg/www.rx8...75e632e1c5.pngMazda spent 40 years development and countless millions with experienced automotive engineers on this engine. .i think they know what they are talking about
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Mazda recommends 5w20 here in the US....and all 5w20 is a GF4 synthetic blend by necessity to reach that viscosity. So, Mazda isn't exactly giving a clear direction there.

There's 13 years of arguing about synthetic oil on this forum. :hahano:

I've run at least 5w30 GF4 synthetic in mine since day 1, along with premix after a while. First engine went to 99k miles..had no specific issues with it, but it failed compression test so I got a reman. The reman now has 60k on it. All premixed, all synthetic. Stock cat too with 160k...and its just fine. Other people have done similar to me, and can't get an engine to go 20k.

Point is, engine life on these cars is more about oil change intervals, ignition health, drive cycle, OMP function, and engine build quality.

Really, I thought in the 1st day of engine class they'd at least explain different oil groups and how polymer deposits are formed and resorbed. Maybe touch on the definition of "synthetic" and how it's a marketing term more than anything else. Maybe even explain exactly what kind of synthetic was tested and found to produce deposits under what conditions. Are you sure it wasn't dogma class?

Some synthetic oils create deposits. Some are fine ( higher quality group V's). Many mineral oils polymerize if you just look at them wrong, but at least they resorb their own deposits. It depends on the base stock and additive chemistry. Mazda even sold their own blend of synth for the Renesis specifically at some point. The Mazda manuals were written 14 years ago at this point. Oil chemistry has moved on, for example metallic ash content has been heavily diminished with the last 2 API specifications.

So yeah, we can play the condescending game all day here, so do you want help with your car or not?

P.S. I like how the very evidence you linked says "don't use any synthetic that Mazda hasn't evaluated". Do you think Mazda has evaluated all of them? Or any at all produced in the last 8 years?

Agreed. There's much more important items to do, like keeping ignition coils fresh, than worrying about "synthetic" oil.

https://cimg7.ibsrv.net/gimg/www.rx8...6562382357.jpg
https://www.rx8club.com/series-i-tec...ne-oil-249264/

Looking at the date, this was published in 2006.

Synthetic oil has changed a bit. Some older synthetic oil actually ate seals in some older piston engines and those manufacturers also said no synthetic.

Personally, my decision is simply based on cost and that conventional is adequate for my use.

I haven't seen Ray's "shed" over at BHR, but I bet it's pretty sweet.

https://black-halo-racing.myshopify....nd-maintenance

re oil
 

I know this debate has been going on for a few years. .but here's the information available to me..
a tsb from mazda said don't use synthetic oil.
all the private rotary engine builders in Europe recommend mineral oil ...to the point they won't honour warranties without proof of mineral oil use...mine included... a year ago...not ten years. .
...any engines torn apart I've seen burning synthetic are gunky brown inside...
mazda have stopped development and research on the rotary as we all know. ..so the last tsb says...don't use synthetic. ..
so all of you lot do what you want. ..put used Mcdonalds fry oil for all i care..
if someone else on this site days you better check the tractor beam and the flux capacitor you better jump to that too..
do i want help? ...
no because the problem is solved. ..
I've no burning smell ..
and your information is wildly inaccurate. .
just to be clear..mazda is based in japan...thats where the tsb came from. ..
thats who built the engine. ..
you yanks really think there's nothing outside of America do you?
its a Japanese car. ..the tsb came from japan...

Oh well if it's from Japan, then I guess there's nothing more to say. Those guys definitely know how to make a rotary reliable.

..
..

..

Cool! You've got it all figured out then. :hahano:

Absolutely! Now if you will excuse me, I will follow Mazda's recommendation of 8000km~10000km oil change intervals with conventional oil in a rotary engine.

Out of all seriousness, another reason Mazda mostly said no synthetic because like BHR mentioned, synthetic oil are all different. Pennzoil Ultra with PurePlus is actually made from natural gas as base stock, while conventional oil is mostly the same.

Did mazda make a reliable rotary engine lol:o::mdrmed:
well i don't think enthusiasts buy these cars for 300.000 mile trouble free motoring...a Toyota corolla it is not.
a beautifully designed perfectly balanced street racer it most definitely is.
a bit of digging and you will find mazdas own oil is a highly refined mineral oil...it may say synthetic. .but its syntheticly engineered. ..
look im not a sucker for main dealer nonsense trying to suck you in buying their parts for no reason. .
but im going with their tsb on this one...the private rotary builders have seen hundreds of rebuilds and are recommending mineral.
mazda says mineral.
private experts say mineral.
mazdas super duper expensive own brand is in fact mineral.
so that's what i am putting in my engine..
​​​​​​​you have spent a few years tinkering with your cars so you obviously know better than someone who has built hundreds of engines.

You can put whatever you want, no objections from anyone. But just realize that the "synthetic" label, and by extension that TSB, are meaningless in 2018. As you say some synthetics are refined crude, others are actually synthesized and their chemistry is completely different, including deposit forming and burning byproducts. The API (the oil standards institute) does not use the word "synthetic" anywhere in their documentation because it means nothing.

https://cimg1.ibsrv.net/gimg/www.rx8...a408e0ffee.jpg



Considering you have 81 posts in 10 years, and contribute practically nothing to the forum, I would rate your opinion's worth at slightly lower than used toilet paper.

Have a nice day.:)

On the contrary I see a few rebuilders recommend synthetic, BHR being one, obviously.

Oils do fall under different classes depending on how they are made. All mineral/conventional fall under a single class so they are all fundamentally the same, with the difference being just the additive package. Test one and you know how all conventional will behave.

Synthetics usually fall under different classes. Mazda likely tested a couple, found that some of them form deposits, and said "no synthetic." It's easier for them because otherwise they will have to test every single one and give people a list of which oil from which brand works and that's too much work.

@bigcajun...ive been building engines for the past ten years. ..not on.this site constantly .. if you got your finger out of your ass and off your keyboard. .maybe get some oil on it doing a bit of actual work. .you might learn something. .

Whoa! We got real keyboard hero here fellas! :lol:

Rebuilding engines for ten years and needs help to find a burning smell.
Mad skillz bro.

Btw, I was a professional mechanic for 10 years and got out of it to get into a better career as a CNC machinist.
I also bought my 8 six years ago with 18k miles on it, used Mobil1 synthetic exclusively since then, now at over 85k on the original engine, so your opinion is crap.

When I do occasionally ask for assistance here, I don't then insult the members who respond.
But if I see some clown parachute in here and start insulting respected members who are always trying to help others with even simple problems like burning smells, I resent it.
Especially when they make asinine statements like oil in intakes is normal.

Act like a jerk, get treated like one.

esp
respected members lol ...what do you think this is...academy awards for keyboard warriors.
respect my balls...
and regardless of whatever nonsense you are spouting I've been on this site since 2008...
i can also play the stalking game. .you have been on it a few years..and you seem to be on it non stop..i don't know how much "machining" or rx8 repairs you get done with all your keboard warrioring...your the first one to comment on everything. .your never off this site...
people like you ruin these clubs for everyone. ..
a little cliche of know it alls ...are you even interested in cars at all or do you just enjoy hoisting someone not in your circle of friends into the spotlight and trying ridicule them ..where you try to make yourself feel superior. ..
its always the same. ..king dick you think you are...its not even about cars ...its just about you making yourself feel superior
if i follow your threads how many times have you done this?...
I doubt if you have ever even had an engine out of a car at all.
you just like bangin away at your keyboard. ..
this site can be a valuable source of information but people like you ruin it by turning it into a platform for personal vendettas and pushing your ego...
Facebook is the place for you. .not car forums. ..

​​​​​​​

Somebody needs a Snickers.

^yep

If you don't have anything to add, just agree to disagree. You are making yourself look like the keyboard warrior you loath.

Again, Mazda's official advice is just "effects of synthetics are unknown, so synthetics are not recommended", not "use a drop of synthetic and your Renesis will shoot out of the car at supersonic speed." And again, I don't think anyone here follow the 8000~10000km OCI the Owner's Manual recommends, or shift at low RPM like the Owner's Manual recommends.

​​​​​​​....

I agree to disagree...

https://cimg9.ibsrv.net/gimg/www.rx8...edc54f17ba.pngStill can't find it
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OK, you obviously know all about me.
I'm a huge troll who comes on here just to inflate my ego and belittle people.
Nailed it.

Now, if you were ever on here to do anything other than have someone else solve your problems for you, you'd know everything you just posted about me is not even close to how I participate in this forum.

But since you're never on here, you really don't know, but that doesn't stop you from spouting nonsense and making a fool of yourself.
​​​​​​​
Since you seem to be the type that has to have the last word, it's all yours.
I'll just leave this here for you little buddy.

https://cimg9.ibsrv.net/gimg/www.rx8...f4406a005b.jpg