I was given 20w-50 in tropical weather, it should be alright.

 

isn't 20w50 too thick?

 

Ya man, 20-50 is way too thick. It need to use oil and therefore it has to be thin. Over time, i think 20-50 will cause some damage or clog up the oil injectors.


Go with what the manual says. I wouldn't even use synthetic because they don't validate it.

 

I was reading a fair bit on this (as I am sure most of us have) and it seems like the numbers on the bottle really aren't that accurate as far as the 'thickness' goes. One manufacturers 5W30 can have an operating temp viscosity of 30, and another's 5W30 can be thinner or thicker. A 50 does sound a bit high, but maybe that particular oil is really closer to 40.

Our manual only states one grade, whereas identical RX's have a range dependent on temp in other parts of the world. Seems odd, there was a good thread on this (EPA Strong-arming I think).

I'd be curious what the engineers that went down to Vegas last summer determined (or wanted to recommend) for a summer weight. I don't know if they are allowed to recommend officially anything other than the 5W20 that was in the car when the fuel efficiency numbers were derived for the EPA tests...

 

the way i see it using synthetic oil is fine. i use re amiymas REsuperG na racing oil in my rx8 and its a full syn oil thats is 0-w30 and i had no problems at all oil looks clean and everything

 

We use Royal Purple 41 full race synthetic, it works great as far as i can tell, but we dont have cats and we rebuild engines after 30 or 40 hours. I was under the impression that the only reason Mazda doesnt recommind synthetic oils is because most have additives that are a good amount more harmful to the environment when burned than natural oils and because oil is injected into the combustion chamber, someone told Mazda that synthetics were a no no. I could be completely off, but it seems like someone told me that at some point. I might look into the REsuperG oil though, i havent even seen that stuff!

 

Back in the late 70's early 80's I use to put 15W-40 in my RX-4
This was a four port 13B. I had no problem with any engine /oil metering pump,
internal part going bad.
This particular engine was bridge ported and had a hunk of Holley 850 DBL.Pumper on it (5-8mpg).Turned around 10000 RPM.
I also put in Bardhal additive, This stuff was the hit back then.
I don't know why Mazda has us all runnig 5W-20 instead of something heavier.
Like a 15W-40. I live where the air temp gets to be 120+ in the summer,
and I would like to see a thicker oil in my car!

 

Yup that's exactly where I was going and it's this document that gives me pause. I've been using Silkolene Pro-4 Full Ester (Class V Synth) Synthetic in my Bike for the last 4 years of hard riding and the internals look nearly new and you really can feel a substantial difference in the Tranny. I fully planned on using the Ester base stock 0W20 weight from Silkolene as well due to it's wonderful performance in the bike, But it's that "Add only non-Synthetic 5W-20" that is causing me concern....

Hell I dunno, and this thread did almost nothing to help one way or another. I've read through 16 pages of mostly opinion and conjecture, largely devoid of any evidence or even links to evidence to support a given position.

I know by and large though as with most everything else in life, you get what you pay for. Buy conventional mineral based oil's, or buy a Top shelf Full Synthetic Ester based product. As has been mentioned, and I've seen the difference's first hand at the shop, the "Blends", and the PAO's are mostly marketing. Mineral oil's and the Cracked HydroCarbons are inexpensive, $1-4 a quart. A full Ester BaseStock Synthetic? Expect to pay anywhere from $10-16 a quart.

BUT... What the hell do you run in the Renesis??? I think I'm going to go get me some Peanut Oil and be done with it. If I'm feeling a little froggy maybe I'll fill it up with Canola.

Sheesh. Oil? Can't be that hard to figure out.

Cannot wait to start the discussion as it pertains to Tranny oils though. Class V Basestock synthetics all around...

 

I found this little quote straight from Mazda. www.mazdamotorsports.com under tech info, miscellaneous, talking about engine break-in of race engines who's lives and performance are far more important than any street engine.

"When breaking in any engine (race or stock), use a low ash content (what is synthetic good at again again? -RG), mineral-based racing oil ( straight 20W or 30W). After the break-in period, change to a mineral or synthetic racing oil (30W or 40W)."

I've used synthetic in rotaries for years and will always use it. It is a better oil. Someone, anyone tell me how synthetic can actualy hurt the engine. I'll wait. It will take a while to get back with a plausible answer.

 

As with all engines use a good quality mineral(dino) based oil for the first two oil changes, this will help all the seal form better due to the nature of the oil breaking down under stress.

After that a fully synthetic oil with cause less gunk in your sump, and will tollerate the especially hard rigors of and engine that runs as hard as our 8's do

 

RG almost has me convinced of the virtues of synthetic, and if I do make the switch, it will be to Royal Purple or Amsoil.

They actually sell Royal Purple at Murray's Auto Parts in Michigan.

 

The reason Mazda and everyone else recommends conventional oils to synthetics only during break in is because it is very important to have the seals breaking in with their mating surfaces. To do this they have to touch each other. Synthetics lubricate too well and slow this process down! After break in how is too slippery a bad thing again?

 

I can’t believe people are still debating the use of synthetic oil. The HEAD of Mazda’s rotary engineering told us at Sevenstock that not only is synthetic not a problem to use, he liked Royal Purple.

You simply can’t go any higher up the food chain at Mazda than this guy (who’s name escapes me at the moment) (Yamaguchi-san -RG), the President of Mazda Japan would just refer you to him. What part of this is not clear exactly?

So we need a doctors note from God saying synthetic is ok? At this point we should be debating the merits of the different synthetic brands, not whether or not to use them.

 

Here's a nice thread on the topic from the 7forum where everyone is closed minded:

http://www.rx7club.com/showthread.php?t=528955

 

I've been using Royal Purple 5W-20 for over 7K miles now. Never been better.

 

http://www.royalpurple.com/techa/faqsa.html#re1

IF you can trust the words of a manufacturer (RoyalPurple themselves) -- they say it's ok for rotaries. Check the link above.

"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." That's more than just conjecture.

I don't think they would say it if it wasn't true. Their business is based on reputation. Getting caught in a lie like that would cause a serious backlash in sonsumer trust of their business. Like I said - I haven't had any problems nor have I heard of anyone having problems as a result of using RoyalPurple (or any synthetic for that matter).

 

altho Im a little sick of this debate, but allow me to put my foot into this (once again)

I just did my oil change few hours ago, this time Castrol Syntec Full Synthentic 5w-20. With Stock Oil filter (last one, I ordered 4 Wix filters and I'll use them next)

So far I've tried Quakers State and Royal Purple. Now Castrol, all Full Synthentic, for 11,000 miles and its running strong (I feel great after I switch to Castrol today. for some reason)

Ahh, Maybe I should just stick it to 1 brand, and I think Royal Purple is on the top of my list.

 

in case anyone is worried about engine longevity and royal purple 5w-20...i've been using it for around 45k miles. (car is at 50,459 rigth now). no problmes at all.

 

it doesn't have to be synthetic to get 5w-20 :-)
'
and while semi synthetic might be better then no synthetic full synthetic is best. plus when choosing a synthetic a TRUE synthetic is best rather then a highly refined dino juice with the synthetic label

 

Assuming that your 8 has gone through 60000 km with mineral oil, will switching to synthetic cause any leaks

 

I switched over to synthetic on my rx7 at around 158k miles. my 76 accord made the switch at around 180k miles. both had leaks to start with. to be honest it doesn't seem to ahve gotten any worse and in a way it might of even gotten better as far as not leaking.

 

Here in Japan I'm using REsuperG 0W-30 synthetic from RE-Amemiya. The Japanese instruction manual recommends the use of 0W-20 oil, and doesn't mention mineral or synthetic. The dealer here uses SYNTHETIC 5W-30. They use the same oil for all Mazda cars, piston and rotary. They have never heard of Mazda Rotary Oil. It isn't in their parts list. Wow.
Incidently, I also have the instruction manual for Europe, Australia & New Zealand. This manual gives no specific viscosity recommendation, it simply gives a table detailing viscosity VS ambient temp. Again, no mention of mineral V synth. Go Figure.

 

I spoke to the service guys at Mazda and they said DO NOT use syntheic oil in my RX-8 (or a blend) as it can cake up the seals. Any good conventional oil is as good at wear prevention as a synthetic if chamged at the proper interval.
don't waste you money, change your oil whenever it starts to get dirty is best.

 

Using Mobil 1 5W-50. probably thats better for my climate. Using it after changing the factory oil at 1500km. No problem what so ever. also I only need to put about half a litre oil to one litre after 2000km or more. Has not been a problem . I have a JDM version Type S 250PS .

 

synthetic protects much better then dino oil even if the dino oil is changed at regular intervals. and your service guys told you that right? doesn't mean a whole lot. my mazda mechanic told me my shifter tower needed replacing because there was a clank near that area. broke the driveshaft a little later later. replaced that and the clank went away.