Engine rebuild oil type survey
 

Hey guys, sorry for another oil thread but I don't believe I have seen one like the one I'm trying to create. I'm going to try this on all the boards, including FB, and reddit. Will create a final thread when all my research is complete.

So my question is for those who owned their CAR or MOTOR from break in period or right after, and went over 100k miles without needing a rebuild. Also the people who DID need a rebuild as well and owned the car or motor since new. I want to know what oil you used. Conventional, synthetic, semi synthetic? Also please include the brand and weight. I know this is the place with most of the OGs and you will provide the best data I think. Thank you.

A million times better question would be .... how often did you change your oil?IMO

Yeah I'd rethink your research approach here. Just looking at cars that made it past some arbitrary post 1/ eliminates the majority of cars, 2/ ignores how the cars were used, climate, other issues (ignition?) and 3/ignores changes in oil chemistry since 2004.

"Synthetic" is at least 3 different types of oil, each of which acts differently. The entire notion that you shouldn't use synthetic in rotaries made sense in the 90s, but we're multiple generations of oil past that. Lumping all synthetics into one bucket is not helpful. It's what marketing does, not engineering.

I consider premixing to be much more relevant.....
Premixed since literal day one, in July 2003, and still has fine compression.

I think this is a great start on a really helpful survey to try to learn what is the most helpful plan to
live with a rotary in/for the long term. There would be a large number of variables to get some definitive data.
Here is a possible data points I came up with. (obviously not complete)

1. miles on engine when acquired. 1.A miles on the engine now.
2. type of oil.l
3. weight of oil.
4. miles between changes
5. driving style (street,time trails,track,old lady)
6. WOT every day, once in a while, never.
7A WOT (red line) how long, 60 sec., 1 mile, 5 miles, Or,.)
7. warm engine before enjoying it.
8. not warming engine before enjoying it.
9. AT or MT.
10. Only the owner drives the car.
11. Ethanol free gas or not...
12. At what mileage did the engine give up the ghost???

Well it's a start............
I think there are enough owners here to get some good numbers if
a good number participate...

Or not...............:)

Worth noting, TrueDelta collected data similar to this for a very long time from hundreds of owners. The owner of TD os himself an RX8 owner. Truedelta.com

I used Mobil 1 but I bought my '04 in 2012 with 18k miles and a clogged cat, so that likely contributed to a failure around 100K

Kyle at Rotary Doctor suggested if I do the 3K oil changes religiously on my new engine, dino oil is probably the best option unless I could afford throwing money away on synthetics.

I have a new engine, already did a 1000 mile breakin oil change.

I was of the opinion that conventional oils were recommended by Mazda due to when the engine was developed, R&D budgets, price and availability of synthetics at the time, and a call someone made. It seemed like there was no way conventional would be recommended if they were to have developed the engine even a short time later when synthetics were the norm. Then the range extender came out, and the manual still says to use conventional... There are still a million unanswered questions on the subject... (it occurs to me as I write this that I have a friend who wrote is phd thesis on something specific to rotary engines... I should poke his brain...) I'm due a rebuild, but not on a right now time frame. I intend to run conventional going forward.

https://cimg8.ibsrv.net/gimg/www.rx8...b0a4b8aa49.jpg

It's my understunderstanding that the recommendation was changed for the American market.

https://www.rx8club.com/series-i-tec...ne-oil-249264/


https://cimg7.ibsrv.net/gimg/www.rx8...eb25c654b6.jpg

Oil weight and frequency of changes since our oil gets diluted is much more important than worrying about conventional vs synthetic. High zinc content oils are regarded as better due to better protection of the stationary bearing.

I have to ask, how does the oil in these cars get diluted ?..............................

Aside from catastrophic failure of the engine......(coolent)

Have you tried using Google or using the search feature in the top right of the website?

I can tell you my car have been eating for last 5 years :d
- permixing 125ml in a tank which most of times I would full the 3/4 empty tank, so put 100ml
always use high octane full +99
- sohn adapter and clean full synthetic 2 stroke oil
OMP increased on all tables, still don't have access to temp dependent table
- full synthetic 10w60 castrol edge supercar changes every 3000-4000mile alt every 1 year,
since rx8 is my 3rd car most of time the 12 months comes first.
Does it need to be rebuilt ? YES, just can not justify it now as it always start, run and never had let me down.

I agree with you on this.


Oil questions are always a warzone. There are reasons the mods banned oil threads...
I will tell you that I start out ownership believing that I had to use Idemitsu blends or death, but I quickly learned that it doesn't matter. The Idemitsu mineral oil also got dark and dirty much faster than the Castrol and Rotella. And in the end, the whole "Conventional versus Synthetic" bullshit is just a massive piles of myths. It's not even just a rotary thing, either. I see it with American classics owners, Nissan VQ forums, Subaru debates, it's everywhere!

Motor oil manufacturers all use lab-developed additives and blends in all their oils. We stopped using actual dino juice in the 70s. Yes, even that bottle labeled "Conventional" probably contains less than 30% Dino anything, if any at all. It's simply a marketing term for the refinement processes of their blends.