So I have 4 quarts of red line sitting home that I have been contemplating using, but just can't bring myself to do it. After thinking about it, I realized this:

There are two types of people presenting arguments, those that are relying on what they have heard, and those that have tried it. Now, every negative post I have read on the subject saying not to use it was based upon what someone read somewhere about why it shouldn't be used. Every person who has actually tried it always claims they have no problems. So the question is, is there anyone who has put synthetic oil in a rotary and had there engine gum up or had some other related problem from it?

 

ill save you the trouble of locating the search.

https://www.rx8club.com/series-i-tech-garage-22/rotarygods-rotary-oil-tech-blog-69805/

rotarygod is a very respected member of this community, and has written many good articles on the rotary engine. this one is on his experiences with royal purple synthetic oil in the rotaries, and is one of the reasons i decided to switch myself

 

Mazda uses synthetic oil in their race cars, where they demand 100% from the engine...including the rotary.

 

But race teams tear down there motors constantly and rebuild them, so a little bit of build up isn't a big deal. But over 60k miles a little bit of buildup from unburned oil could cause a problem.

 

This is the *official* stance from MNAO, per their 'Product Update' DVD that people (including myself) have received.

"The seals inside the RENESIS engine is COMPATIBLE with synthetic motor oil, but due to the fact that long term effect is still unknown, Mazda does NOT recommend use of synthetic oil"

and as people stated above, i have YET seen anyone posting about a failed RENESIS engine that have been determined that synthetic oil is the cause, and all the blown engines that have been reported were in fact using conventional oil...

 

pretty interesting read.

 

1 actual result is worth more than a thousand expert opinions.

 

I just change the oil at regular intervals :D . Who needs synthetic. As far as synthetics causing failure, I'd imagine that'd take 10's of thousands of miles if it would occur.

 

i don't know about 1 as that could be an anomaly. now, you get several actual results, and that starts adding up to real worth really quick. (but i understand what you are getting at )

 

Why not just change your mineral oil more often? I change mine every 3,000 miles or less...

 

Well that's what I have been doing, but now I'm turbo'd and synthetic is much better for turbos. It won't coke up the bearings nearly as much, or break down from the heat of the turbo as much.

 

This is precisely why I wont use synthetics in rotaries until the Factory (MC) recommends or approves its use.
Which I have said many times before.
And yes, I consider Mazda Motors Japan (MC) the "experts" in what is rotary.
They are the rotary gods where all other car manufacturers gave up or failed.
There is still NOTHING like a Rotary powered car.

 

I asked the head rotary designer today if we can use synthetics or not. Let's just say that I have a very big smile on my face!

 

This sounds reasonable. And says nothing about "burnability", "deposits", "little gummy *****", etc. So can we put those to rest?

The only concern left is long-term effects on the seals. Given that this engine has been on the road for over 2 years even that concern should soon be gone except for those who might still agonize over the 20, or 100-year implications :D

 

my turboed 8 gets nothing but Royal Purple. I switched because of all the new heat introduced by the turbo. running great so far.

 

Ok here's the official scoop on the oil issue. As I said earlier, I asked the highest people on the planet when it comes to rotaries. First I'll start with Rick Engman's position as he built all of the engine's for Downing. I looked at Rick and just quite simply said, "synthetic oils". His response was, "I wouldn't use anything but synthetic oil in a rotary". Thankyou Mr. Engman! All of Downing's race cars use Valvoline synthetic. He said it doesn't matter if it is a race engine or not. I also told Mr. Engman that many people say you only use synthetics in a rotary because it gets rebult all the time and that it doesn't matter what happens to these engines. I can't post what his opinion are of these people! He did say their engines get 100 RACE hours of use between rebuilds. The Courage is using experimental engine parts that were last used in the 80's and 90's! They care more about the longevity of the engine on a race car than a street car so some people's logic is VERY flawwed.

Now onto Mazda's position on synthetics since I know that the opinion of the smartest rotary person in the U.S. isn't good enough for some people. As I stated earlier, I asked the head of rotary engine development for the past 30 years at Mazda. He designed and built the 787B engine too. In very broken english he told me that not all synthetics are created equal. some are better than others when it comes to mixing with fuel in the oil metering system. The oil metering system is the key. It is NOT with swelling seals. He said that because some oils work very well and others not as well, it is far easier to just officially say not to use them than to say which ones to use and not to. This has actually been speculated for a long time and now we know it's true. I asked which synthetic oils he does not like. the answer is very surprising. The worst synthetic oil for the rotary according to the smartest rotary engine person in the world is Mobil 1. At least Valvoline and Royal Purple are fine. Didn't get any others listed. Rick Engman did say that decades ago there was an issue with some swelling of seals with old synthetic formulations but these have long since been resolved.

To all the people who keep getting on my case and others for using Royal Purple, WE'VE BEEN THE CORRECT ONE'S!!!!!!!!!!!!!!!!!!!! :D

 

THANK YOU, RotaryGod. You have vindicated all of us who have been using synthetic in our rotaries (except the guys using mobil 1) i guess all the nay sayers were just a little not wrong :D

 

Thank God, i mean rotarygod for pointing out the Mobil 1. That was the first one on my mind if i were to use synthetic since I don't have either redline or purple here in my country.

 

First of all, a big THANK YOU to RotaryGod for verifying the most important piece in the rotary lubrication puzzle (solvency in fuel). Our oil injection system is emulating pre-mix, so solvency in fuel is golden.

I have been a user of Mobil1 from the late 70’s. I accidentally dropped some Mobil1 in fuel (gasoline). I can personally state that Mobil1 has poor solvency in fuel.

I come from a background of air cooled motorcycles and lawn equipment. The wide heat range of these equipment require a heavy weight oil, because of the clearances required in a cold start condition. The oil actually “makes up” the wide clearances until the engine reaches its (high) operating temperature. A good PAO is great in these applications. In this case, poor solvency in fuel is a plus. This is also true in liquid cooled piston engines that have poor cooling, and no oil coolers (Miata).

The tribologists that formulated Royal Purple deserve a round of applause. They came up with a PAO that has good solvency in fuel. After my current regimen with Havoline, and the necessary UOA’s, I plan to switch to Royal Purple. The experiences in Las Vegas make using a good PAO (because of the higher carbonization temperature) even more important.

 

Sure seems like it would have been much easier to just have 2 oil resevoirs.

I mean, if you let people know when they buy the car that there are 2 oils levels to check.......

All this engineering to try and get around some ignant people.

 

I can also ad that in Australia we also have those "Highest People on the planet" too who have decades of experience with the Mazda rotary engine. Alan Horsley started at Mazda Australia in the late 1970s and still is their chief mastermind/engineer with anything Mazda, he is the man who in Australia can claim the success of the first RX-7/Peter Stuyvesant Racing wins and titles 1980s, the FD RX-7 Turbo 4 year in a row wins at the Bathurst 12 Hour event over the Porches, the Retailed RX-7 SP Turbos, the first MX-5 SP Turbos and last months Mazda Australia RX-8 Turbo Prototype.


To this day he and Mazda Australia/Japan do not recommend Synthetics in Rotaries, as the 2003 RX-8 Tech Bulletin stipulates.

UP to 100 hours of use in a Racing rotary before a rebuild has no correlation to long term use (years) in a domestically/privately owned RX-8. As I have said before racing rebuilds renew all the oil control seals and springs and O rings, at EVERY rebuild.

I thought the head designers of the rotary are in Japan and the father of the Japanese rotary was Mr.Yamamoto, THE Mazda rotary god/engineer and a former president of MMC Japan. I believe MMC Japans wealth of knowledge/data would far outweigh others.

 

ASH8, no disrespect intended, but your only piece of hard evidence is the tech bulletin. RG clearly states why the tech bulletin says what it does. I really didn't need it as I made my decision long ago and haven't looked back. But, RG's post does explain why Mazda doesn't officially recommend synthetics. They aren't in the buisness of promoting a particular brand. Makes sense to me. It seems that you just can't accept that Mazda's official position on synthetics ensures that the majority of 8's are well protected (with possible exception of the AT's ) , but that the unofficial position could buy you a lot more protection.

 

Interesting. Hooray for Royal Purple and Valvoline.... . The (fact?) that possibly the worlds best selling synthetic oil (Mobil 1) is persona non gratis is disturbing to those who have used it. Kind of lends support to the unnofficial "no synthetic" position that has prevailed up until now. What do we think of Havoline, Castrol, Amsoil, Shell, Red Line, Penzzoil etc?

RG's guy has shed some light on the age old argument and cleared away a bit of fog, but the end result has cast a shadow over all but two synthetic oils. At least we now know two are good..... :D .

 

Well, at least we know what the issue is...so the next question must be how different -- if at all -- is the oil metering system used in the Renesis relative to earlier engines?

 

I'm not sure which experts in Australia say no but I talked to the top rotary engine person in the world (Yamaguchi!)! He has been the head of rotary development for 30 years. You can not ask anyone higher!

btw: I need to post my picture with Yamamoto-san, Yamaguchi-san, and Koby-san. Those are the Mazda people who I've been talking to for 2 days and the ones I've spoken to about synthetic oils in the rotary and I personally know Engman and Downing and trust their opinion highly.

I even won a raffle at the banquet which was a new book written by Koby. Of course it is in all Japanese but there are only about a half a dozen of those books in this country and mine is signed!