Cumulative Synthetic Oil Discussion
 

Yes, i've read the thread about synthetic oil vs. regular oil... and i do own an rx7 Efini so i know how rotary engine works... ;)


the manual for the 8 mentioned:

"Recommendation oil [Pure-Motor-oil golden SJ]
API SJ/ILSAC GF-2,SAE 10W-30"

am just wondering what does this mean? can the rx8 use synthetic oil now? i know MS/Dino/Mobil1 works for rotary engine but how about other brand?

any input would be great... tanx in advance...


-D-

Re: oil for the rx8...
 

:eek:

whaaaaat?? the owner's manual??

yup yup... funny?? :D
EASTMOON one of our forum member in JAPAN.. hehehe got his rx8 allready... ;) so for expert out there what does it really mean?

ohhhhhhh, yeah i knew he had one, i thought that you did too!! :D ahahaha... never mind :)

no problem dude... ;) like some members have said... "he's one lucky bastard!!" hehehe

So from what I understand, rotaries eat up oil, its part of their function; not a lot, but more than a piston engine. With understanding that, isn't the purest, cleanest oil what should be used for the Renesis or is that not as important as the grade?

unless you're buying used oil (as no one does) than any oil is "clean and pure" as you put (clear of "contaminants" to an acceptible level), even the cheapest kinds.

what is really key is the combustability of the oil: if it can really just burn up nice, quick, and clean (like lighter mineral oils do), then it is better suited than an oil which doesn't burn quite so well, and cokes up the seals (like a heavy, burn-resistant (which would be a bad characteristic in any motor) synthetic or something).
that is the talking point: will synthetic burn off as nicely as a mineral oil?? and secondly, is the synthetic (being consumed at a constant rate) worth all that extra money for the protection it offers to this engine?? (although that's a different discussion)

From my technical understanding: The "conventional" Wankel had the intake/outtake ports on the front, so the oil (lubricating the apex seals) was drawn out by the brute force.... I believe that with the side mounted ports of the Renesis comes the huge decrease in oil consumption because it is not sucked out this way any more. Nevertheless this IS an issue and I would surely follow the manual in this point. And always check for the good sap every other refueling.... :o

5w-20 semi-synthetic
 

can I use Valvoline 5w-20 semi-synthetic oil on the 8's. Thanks

The most important pieces of info on the label of the carton are the API Service rating and the ILSAC specification. Ensure that they are API "SL" and ILSAC "GF-3".

Additionally, I've been advising folks to look for BOTH Honda AND Ford specifications for the new 5W20 oils. These credentials indicate the oil meets or exceeds the manufacturers' specs. The Honda spec is good, the Ford spec is best -- it's currently the most rigorous standard for 5W20 oils.

BTW, the "semi-synthetic" or "synthetic blend" label on the oil is, most likely, simply for marketing. I'm not familiar with the Valvoline brews, but it is most likely a blend of highly-refined mineral oil base stock (group II, II+, and III), as opposed to having any "pure" synthetic oil (group IV) base stock in it. Nowadays, the term "synthetic" is more closely associated with performance characteristics, at least for marketing, than differentiating between man-made and dino oils.

Again, as long as the oil is "SL" and "GF-3" you should be OK.

I don't want to revive any dead threads, but the new Castrol Syntec 5w-20 oils clearly label Ford spec right on the front. Does that mean anything when it comes to the Renesis? ...i.e. Can I now use this synthetic oil in my RX-8? Thanks.

What does the Owners' Manual say?

First off, I highly doubt the "syntec" formulation is "synthetic" in traditional terms. It's merely a marketing term. It's more an indicator of performance level or standard for the oil, as opposed to a chemical formulation. It was, in fact, Castrol's court victory against Mobil (mid-1990's?) that paved the way for ANY formula of motor oil to be branded "synthetic" so long as it is highly refined enough and performs well enough. The Syntec is most likely a blend of highly refined mineral oils (probably group II+ and group III), with a proprietary additive package (thus, they can call the oil "synthetic" and charge any price the market is willing to sustain...)

I'm not familiar with all the tech details of the Ford specification for 5W20 oils, but let me reiterate that the most important specs to look for on the label are simply this: API Service SL and ILSAC GF-3. These are MANDATORY specs. Any oil with these specs will be good oils to use.

The Ford spec is based on measurements of how well the oil holds up and protects against wear over a long duration. IIRC, it was in excess of 150K (simulated/tested) miles. Oils with this spec, in addition to the API service SL and ILSAC GF-3 ratings, will be your best bet.

API Service SL and ILSAC GF-3.

Ciao!

Question regarding synthetic oil change
 

My appologies if this has been posted before, I tried a lengthly search and turned up nothing.

When switching to synthetic, has anyone drained the coolers and lines to change all of the oil? This seems like an easy proposition, but I have hit a snag. How do you prime the pump, coolers, and lines? Since nearly half of the oil is sitting in the coolers and lines, I would like to change all of it. Any ideas?

I simply wouldnt recommend goin to synthetic. I was told its so slick and the rotor seals wont set.. ?

Synthetic has been covered many times. The only oil requirement is that it be API certified or ILSAC GF3, and 5w20 grade.
The manual does not prohibit synthetic / say to use synthetic, nor does it say to use regular oil.
If synthetic would be detrimental to the car it would say so in no uncertain terms. Period.
As for flushing out the lines and cooler, I have not heard of anyone doing this.
2-3 oil changes, plus the adding of oil in between and you should be fully converted.
It might be a nice project to undertake though.

I'm currently running durablend synthetic oil in my 8 and I only have 3k miles. I don't think it'll be a problem. And you shouldn't have a need to flush all the oil out of your system. Just change the oil every 3k miles and you should be running full synthetic in no time.

Also remember the stock oil's already semi-synthetic....

synthetic oils will mix perfectly fine with non-synthetic oils

Like they say, don't worry or bother about flushing the left-over oil. Synth and non-synth are perfectly compatible, so after about 3 changes you'll be effectively 100% synthetic.

Regards,
Gordon

Thanks for the help guys.

Synthetic Oil (answer from Mazda)
 

I wrote to Mazda about the use of Synthetic Oil in the Rotary engine, since the manual doesn't say one way or the other... here is what they had to say....

Dear John,

Thank you for contacting Mazda North American Operations. I appreciate
the opportunity to respond to you.

In regard to your inquiry, Mazda recommends using 5W-20 engine oil for
the Mazda RX-8. Please understand, Mazda hasn't done any long-term
testing using synthetic oil with the RENESIS rotary engine. As such,
we don't recommend the use of synthetic oil.

Regards,

Lisa Lasky
Specialist, Customer Assistance E-Business

Ambiguosity.....
 

That, too is relatively ambiguous......

"We haven't done the testing, so we can't recommend...."

Does not say "we recommend you don't use", simply that they have no clue. :o

S

I'm a former 2nd gen and 3rd gen owner. The reason that some people believe that running synthetic is bad for rotaries traces back to the oil injection system used to lubricate the apex seals. Some people think that synthetic oils will not full burn out of the combustion chambers and leave behind a deposit that overtime will eat away at oil and water seals. They think that mineral oils burn better and don't cause this problem since they don't leave behind as much or any deposits. It hasn't been proven that this is true, but there's a lot of people that believe this through prior experience. I think the 3rd gen RX-7 injected something along the lines of one quart of oil every 1,000 miles. Since the RX-8 apparently injects one quart of oil every 10,000 miles, I would imagine that this problem (assuming that it's true) would be far less on the RX-8. In conclusion, I'm uncertain whether synthetic is bad for rotarties, but this is why there is concern about its use.