New Yorker

I wrote Ron Ananian, radio's "Car Doctor", to get his take on motor oil for the RX-8. Here's his response:

Since this is a rotary and a new one I felt it best to get some info right
out of Castrol. This reply is from Tim Miranda, their oil "guru". Tim spends
most of this time in the lab analyzing and formulating. We can't get any
higher or better than him for specific oil issues such as yours.

His answer follows.

"Good question on the RX-8 (also applies to the RX-7). The recommendation
from Mazda for high quality non-synthetics in the rotary engines is valid.
The reason is that because of the mechanical design of the rotary engines,
there tends to be a very small amount of engine oil swept onto the interior
walls in the area of the cycle where combustion takes place. Mazda prefers
this oil to be burnt off/volatilize off so as to prevent formation of
deposits. Synthetic oil typically has a higher threshold for volatility and
burn-off so that is why conventionals are specified. It is a bit of a
2-stroke engine effect.

Hope this helps."

Best regards,
Tim

Ron

Ron Ananian
The Car Doctor

That's good enough for me. I'm stickin' with non-synthetic. Personally I doubt that synth would hurt anything, and sure, it might even be better. But after reading this—and every oil thread here—I feel comfortable with what Mazda recommends.

otherside

Oh boy, here we go....by the way, Mazda recomends 5/20.....

New Yorker

Oops, that's what I meant, 5W-20. That's what I use. BTW, are we to not post any new oil threads? I don't mean to **** anyone off or violate some rule I may have missed.

otherside

LOL, there has just been alot of debates about synthetic and non synthetic here. I say use what you are comfortable with...

tiggerlee

^I agree.

NoTears316

The next post MUST include something about premixing or this thread fails.

otherside

Ok, I'll bite. dont do it, it clogs your filter!!!!!

New Yorker

Seriously, I'll delete the thread if it's just gonna get people pissed. Whatever.

Easy_E1

iTrader: (2)

It's always nice to have another opinion on the subject. Especially from Castrol.
But hey what do I know.



That was not an open Flame invitation either.

ken-x8

Very old, much discussed topic. But I don't recall seeing a post with an opinion from a radio personality and a personal response from an expert in the oil business. Seems like worthwhile post to me.

Won't change anyone's opinion, of course, but it's good info.

Ken

9krpmrx8

iTrader: (46)

Great post, my friend sells oil for a private oil company and is somewhat of a "guru" himself and he concurs. It is nice to have an expert opinion instead of a bunch of guys talking out of their asses.

Again, thanks for the post.

nycgps

iTrader: (1)

Fact is always better than 100000000 experts *opinion*

I use it, I have no problems, so does TONS of other people, no one can prove that Synthetic causes problems except for 30+ years ago.

This is just like going to a *so called* tunner shop and the guy there just tell people that *Rotary cannot handle boost*.

Can Rotary handle boost?

Talking out of their asses ..... Fine, I can say the same thing back to whoever that expert was, I dont know who he is at all but hey, I can say the same thing *oh according to Mazda ....* yeah ok. Very *EXPERT*. and that 5w-30 thing .... its not that *hard* to understand those ..... I dont know **** about cars before, I start digging right after I got my 8 .... in about 2 months or so Im dare to say that out of all my friends, Im already the *most advance expert* they ever know. and hey Im still a newbie even today, its just an example.

Im just the type of person who loves FACT(s) than one's opinion. Sure sometimes they're helpful. Just believe what you want to believe, but dont bash ANYTHING without ANYTHING to back yourself up. oh I mean REAL facts, not OPINION. you know, something more scientific ?

Thank you for reading.

CarAndDriver

TO THE OP: Why don't you edit it to saw 5W-20 instead of -30?

9krpmrx8

iTrader: (46)

Dude, you make no sense. This guy works in a lab that developes motor oil. What facts do you have? He is an expert because he has spent years studying facts. You my friend are the perfect example of someone talking out of your ***. You are questioning the opinion of a guy who probably has an advanced degree in engineering.

Lots of people smoke that never get lung cancer, does mean that smoking does not cause lung cancer?

nycgps

iTrader: (1)

Same thing for you, tons of people use Synthetic without problems, Does that mean its bad? oh yes it must be,cuz no one can PROVE that Synthetic oil causing problem.

Making oil does not mean he has any experience in Rotary engine, look at his words, thats so *got it from the Manual* kind of speech. WoW very expert opinion.

I must be talking out of my *** that I have been using My FULL SYNTHETIC OIL for 24K miles and oh guess what, I have no problem. Ahh maybe I didnt use it long enough.

Oh Wheres RotaryGod when we need them? He has been using it for what, 7+ years? Is that long enough for you ?

Show me something, not *blah blah blah blah blah*.

nycgps

iTrader: (1)

forgot to add, what makes you think that working there means he is an expert. That might be true for some but, for example, tons of people working in the *IT* department of *name your company here* does not know **** about computers. Good example would be my good old school, that dude dont know **** he cant even solve a simple video display problem and hes getting 70K a year. good job man.

New Yorker

My bad to pose that part of the question incorrectly—I meant to ask if 5W-30 or 10W-30 (whichever Mazda recommends for the REST of the world) is actually better for the engine than the 5W-20 they recommend in N. America…d'oh! So really, because of my carelessness, we don't know Castrol's opinion on this.

Therefore… I'll edit to delete the viscosity part. (Again, sorry—I would have loved to know if they believed 5W20 is as good as what the rest of the world uses.)

devildog1679

+1

ken-x8

My brother had a Toyota in which he never changed the oil. At 24K miles he had no problems whatsover.

At somewhere above 70k miles he left a big puddle of sludge on the Jersey Turnpike when a rod went through the block. But at 24K he would have sworn that changing oil was a waste of money.

That said, there are some long-time rotary folks here who have God knows how many miles of experience with synthetics and find they're OK. I'll believe them.

Something I find interesting is that the early issues with synthetics were from incompatibility between one brand and rotary side seals. That problem is gone, but the prejudice against that brand still remains. Now the issue is what Tim from Castrol says: whether injected synthetics will vaporize and burn as well as dino. If that ever gets debunked, I wonder what the next issue will be.

In the meantime, I'll keep using dino because I think regular oils these days are really good. I've also got over 200K miles on my Accord, regular changes of GTX, and no mechanical engine problems.

Ken

nycgps

iTrader: (1)

This is what I would called an intelligent speech.

unlike morons like 9krpmrx8 who has no useful information at all but to spread bullshit.

I have nothing against Dino oil, I think its fine for rotary use, I never said Dino is bad cuz I know they're good. The only diffs between Synth or Dino came from the base stock. Most of the addiditive are the same anyway.

The thing is that I have had my own Synth oil history and I feel good about using them. but for some reason certain people just come and BASH synth oil without any Truthful fact(s) to back themself up.

oh yes, base stock is what it determines if its Synth or Dino oil, so let me ask something, why is something with less impurities(Synth, Group IV+ oil and some Group III oil, like Castrol Syntec) will get more deposit ? Because they have less impurities ? Like I said, most oil would have the same basic addiditive in them, to prevent corrsive stuff, to prevent high heat, etc. Dino or not. So what makes Dino oil superior for combusion than Synthetic ? because Synthetic can withstand higher heat? then tell me which synthetic oil can withstand at least 1500f+ degrees of heat ? I really would like to use them, and change my OMP to use only premix.

Mazda's TSB ? As we ALL know that,this engine if u dont rev the **** out of it every once in a while you will see something like that. People who had failed engine mostly use Dino oil. So what sup with that ?(base on the information I've gathered on this forum)

nycgps

iTrader: (1)

Even he did understand your question the way you mean it, I dont think he will say something like *its ok to use 5w30*. because he is working for a company and he is helping that company to answer those question(s), so even if he personally agreed to the answer(5w20 vs 5w30 or whatever), he is NOT suppose to say it because his company(or himself) might get sue by people who actually followed them and run into problems(welcome to america), safest way to do this is to follow auto companies guidelines, before anything else. better be safe than sorry.

He sound like a cool guy to deal with, but to me, opinions are opinions. I still prefer to trust myself, especially when I have personal experience with something for a while and it has been known that it actually works(for me)

Stavesacre21

i personally am glad to see an opinion of someone outside the rx8club for a say in this. It sounds like they went straight to the top by asking castrol. I found it to be a rather professional reply. I know the debate has been beaten senseless, but if Mazda and castrol both clearly point towards it...hmm.

However, to everyone their own

Thanx for the post

nycgps

iTrader: (1)

Rotary Engines

Can Royal Purple Motor Oil be used in a rotary engine?

Yes. A rotary engine is a modified four cycle engine that recommends the use of an API licensed motor oil for street applications.

More information and FAQs on lubrication of Rotary Engines:

In a rotary engine, the oil lubricates the eccentric shaft bearings, thrust needle bearings and rotor bearings similar to a crank and rod bearing of a piston engine as well as being injected into the combustion chambers to lubricate the apex seals, corner seals, and side seals helping to create the sealing mechanism doing the equivalent job of the piston rings.

Royal Purple provides outstanding protection for the e-shaft, rotor bearings, thrust bearings and is suitable for the oil injection system as it has proven to run cleaner than other oils and is an excellent choice for rotary apex seals, corner seals, and side seals.

Mazda makes a statement in the Owner’s Manual not to use synthetic oils in a rotary engine, why do you say that it is OK?

Royal Purple has performed seal compatibility testing on the components used in a rotary with excellent results, including older rotary engine seals dating back to the Cosmo. Royal Purple’s Technical Services Manager David Canitz has been an owner and racer of rotary engine cars and has used synthetic motor oils in rotaries since 1985 with excellent results. He has been trying to find an answer to this Mazda statement for the last 18 years.

In the early development of synthetic oils decades ago, there were purportedly some seal compatibility issues. Today’s synthetic oils do not have the compatibility issues of the old oils. There is no substantiated evidence of seal compatibility issues with Royal Purple.

Here are some facts:

The Mazda Factory racing departments recommend and use ‘synthetic’ oils including the winning 1991 Leman’s 20-G 4 rotor Mazda 787B.

MazdaComp USA printed manual (now Mazdaspeed) recommends the use of synthetic oils for racing conditions.

Royal Purple Motor Oils have been used in rotary engines (both race and street) for ten plus years with excellent results.

Royal Purple Motor Oil is compatible with the bearing material, sealing elastomers, and combustion seals used in a rotary engine.


I heard that synthetic oil doesn’t burn like mineral based oils and will coat the inside of the engine with deposits.

If this was a problem with synthetic motor oils in general, then all internal combustion engines using a ‘synthetic’ would experience increased deposits on internal surfaces. The opposite is actually the norm.

Conventional four cycle motor oils will typically leave deposits of carbon and ash when injected into the rotary apex seal, corner seal, and side seal areas. Royal Purple’s motor oil actually burns cleaner due to the synthetic base stock being free of contamination and many of the additives being ‘ashless’. This may not be true for all synthetics but Royal Purple has been proven to work extremely well in rotary engines.

Royal Purple’s formulation of synthetic hydrocarbon motor oil does burn at the nominal combustion temperatures experienced in both street and racing applications, whether normally aspirated, turbocharged, or supercharged. (500 – 1700° F idle to race rpms typical combustion temps)

Will the synthetic oil effect the oil seals?

No. Royal Purple’s Motor Oil is fully compatible with the elastomers found in rotary engines as well as more conventional piston engines. The oil seals, housing seals and other elastomers used in rotary engines typically consist of Buna N, Nitriles, Neoprene, or Viton materials which are also commonly found in piston engine cars.


This has been posted like years ago. It does sound like a marketing stuff but its still facts, I dont understand why no one take *this* opinion into consideration at all.

tmak26b

haha funny you guys brought this up. I have been going back and forth on what oil I should use on my own personal car, so I have been researching quite a bit. Let me add a few comments.

#1 Why 5W-20 in North America only? FUEL MILEAGE. 5W-20 is the hybrid of oil, they suppose to give you a .2% gain in gas mileage compare to 5w-30. Personally now i know what it is, I will probably switch back to a 5w30 for more protection in the summer. Heck, even higher grades in the hot days.

#2 Castro Synthetic (Syntec), they are actually not real synthetic fluid. They are based out of group III oil, not group IV or V oil like RP or Redline or Amsoil. There has been debates about Mobil 1, I am still waiting on answers from them. With all that said, it is a GREAT oil. The only thing that **** me off is that I was paying $6 a quart for non-synthetic oil.

#3 My personal experience, why would you pour $6 into the rotary engine every 1000 miles when you can do the same job with oil that is half the price. With the oil change interval like hte RX-8, I say go with a regular oil. I put 120K miles on my last rotary engine, it had 170K when I sold it. All I did was change oil every 3K, check it every 750 miles. It used about one quart per 1500-2000. The RX-8 is eating it at 750-1250 miles per quart

#4 One way to battle carbon is to keep the oil fresh, tune the car up and rev the car a few times a day if you can.

ken-x8

I saw nothing wrong with 9krpmrx8's posts. His first one in this thread conveys much the same info as New Yorker's original post. He doesn't have a quote and doesn't name names, but it's still the same: citing someone in the oil business who goes along with Mazda's recommendation. No need to take any of this personally.

Ken