Da P-Funk!

aaaahhhwright!

i will post pix at the next oil change and every 1K miles.

MMM. Crow! Tastes like chicken! (At least i hope so - i may have to eat some...)

Stueck

Wrong


I use Royal Purple 10W-40 in the Rx7 and in the Protege. Never had any problems.

_Kansei_

^^ I probably should have specified renesis in that case.

According to everything I've read royal purple burns cleanly but most synthetics leave a film and should be avoided.

http://www.mazdatrix.com/faq/synthetc.htm

http://www.mobiloil.com/USA-English/...ry_Engine.aspx

As said above on mobil's site, it basically comes down to being a warranty issue. They will void your warranty if something goes wrong and they find out you were using synthetic oil. Basically if you 'blow the engine', they will request records of a few recent oil changes.. if all you have is receipts saying you bought synthetic, bye-bye warranty. It's crappy but since Mazda found problems with some synthetics they had to just say a simple no in the owners manual.

Royal Purple themselves have done extensive testing and have lots of evidence to show that their oil does burn cleanly and lubricates well:
http://64.233.169.104/search?q=cache...ient=firefox-a

but your typical shady auto parts store synthetic may cause issues.. of course YMMV

see, I didn't want to have to go into that level of detail (as this isn't a rotary site :P )

Almost forgot: all this having been said, Royal Purple is not a true synthetic oil. There was a lawsuit between Castrol and Mobil in the I think 90s and the outcome of it was that any oil that is reformulated enough can be called synthetic, though derived from non-synthetic base stock. Though I do often use Royal Purple, one must realize that it is a hydrocracked, fake synthetic oil.

SteveO

About the only thing synthetic my rotaries see is gear and diff oil. Synthetic is a huuuuge no no for ANY series rotaries. Dino oil and 87 octane...praise be to the triangle.

Tercel89

SteveO , since we are on the topic of oil usage , type and consumption , I believe it read a fews years back that the rotary engines have a limited life and even from the time they are new they will use/burn a little oil unlike a piston engine that will not . Can you comment on this or if its true based on what you know? I think it was something about how the the rotary's use something (cant remember the part name) but it is equivelent to what the piston rings do like holding the oil back away from the combustion chamber . It said the oil eventually gets past the "oil flaps" or whatever its called and will naturally burn away the oil . Now this is what i remember it said but its been like 2 trs ago or something . I read it breifly in an automotive book while waiting in a dentist office , so some of it may not be exact.

Roddimus Prime

rotary engines actually have oil injectors, like fuel injectors. These are designed to squirt oil at the leading edges of the apex seals to lubricate as the seal compresses against the housing. Naturally some oil is sprayed before and after the seal is made so there is oil leftover in the combustion chamber. This causes it to burn and eventually your oil level will go down.

On our RX8 we noticed maybe a half quart gone after 4k miles.

SteveO

Matt answered your question pretty well.

Oil always ends up in the combustion chamber, where it burns away. This is also the reason RX7s smoke (esp on cold startup, high revs, etc etc). Its caused by oil collecting inside the rotor housing.
The oils function in a rotary is to lube the sides of the combustion chamber as to let the seals on the corner of the rotor (apex seals) glid across the housing.

Alot of apex seal problems are due to lack of oil or carbon build up.

There are also oil seals that sit on the rotor itself, between the eccentric shaft, that keeps oil out of the chamber.

Rotaries as they get older will smoke more, and will burn more oil. In boinger motors this is a bad thing. Not so much in rotaries. The smoke and the oil burning means that the chamber and e shaft are getting that much more lubrication than normal. Which is a great thing.

Im dont beleive this is part of your question, but the biggest issue with rotaries oil system is a little peice called the 'oil metering pump'. Its a tiny hydrolic pump that tends to go out w/o warning. Leaving you with no oil being pumped into the engine.

Alot of people, myself included, premix oil with the gas. I still keep regular oil in the resevoir, but I also mix part Marvel Mystery Oil in with the gas as a back up. Some people pull out their entire oil system and run pure premix. The cars run just fine like this. Usually better (especially on FBs and FCs) due to the omp already pumping less oil than factory specs.

Sorry to write a book, but rotaries are very intricate, but very very easy to deal with once you have some knowledge. Wish all cars had them.

Roddimus Prime

I was debating removing the OMP off my FC as well...it's a track-only car anyway so it wouldnt hurt anything.

p.s. I think patrick is buying my audi and FC...he's coming over this weekend to look at it.

Stueck

I removed the OMP on my 82, and mix 1/2oz a gallon. I just used regular 2stroke oil for outboard marine engines, it has 2C-TW or something like that in it. 2stroke oil is oil designed to burn, which is better to use than 4stroke oil

SteveO

I just like MMO because it smells like candy.