NEWBIE

I have been shopping for an RX-8 in the last 3 wks. I keep on hearing about how these Rotary Engine use oil and one should keep a quart or two in the car and check it every other fill up or every 1000mi. Why do they use oil? Where does this oil go? Does the car burn it?

Furthermore, I heard that one shouldn't use Synthetic oil. Is this true and why?

 

a. rotarys take alot of oil and gas to operate so you should check it at least once a week to make sure it has some in it. I believe the rotary engine burns it. I don't know though. Just keep a quart of oil in your trunk or something and once a week check it, if it's low put some in.

b. Synthetic is a questionable debate, some use it, some don't, some recommend it, some don't. Bottom line is MAZDA never really tested the rx8 with synthetic oil so they dont' recommend it. Next oil change i'm switching to synthetic. I've been using castrol 5w20 regular oil and now i'm going to castrol 5w30 synthetic if worse come to worse i'll just do another oil change and go back to regular oil.

 

I believe that in order to properly lubricate the rotors, small amounts of oilneed to be in the combustion chambers. The oil consumption is part of thenormal operation that keeps the motor healthy.

Be aware that you won't see a drop on the oil pressure gauge that tells you that it's time to add oil. If you wait for the pressure drop, it's too late.

As far as synthetic oil goes, there are a couple reasons why Mazda may not recommend it. Synthetic oil has properties a little different than regular oil, and one of those properties is that itfindsits waythrough tighter spaces than other similar viscosity oils. I can't use the stuff in my original Mini -- it all just ends up on the ground, very quickly. At pressure, it finds the cracks.

Also, every motor has a certain capacity to deal with crud. As long as the motor can deal with the crud as fast as the drud is created, the motor is happy. If you switch to an oil that creates crud faster than the motor can handle, you get problems unless you're doing extra maintenance. I don't know if this is the case, but if synthetic oil builds up a little more gunk than regular oils, a manufacturer might say "don't use it". Conjecture on my part, though.

 

I used to own and work on early British cars. No matter what you put in them, or how careful you are w/seals and the like when rebuilding them, they leak. It's a fact of life... and British cars.

Synth's do find smaller places easier than conventionals. This helps them insure proper lubrication in all places at all times. And yes, it's normal for a rotory to use oil and for the reasons Squish states.
Synth's, especially good ones, do not pick up and redistribute gunk as easily as conventional oils.
It used to be the case in the early days of synth's whenchaning over from conventional oil it would gunk BADLY, but no more.

As far as using it in a rotory...? I don't know what the results might be.

 

the motor has what is called an oil metering pump. that pump meters in a little bit of oil with each combustion in order to lubricate the apex seals of the motor. you can use synthetic, but not any synthetic. synthetics don't burn the same way that dino oils do. i have heard that a low weight royal purple will work well. check with this guy. he is a rotary owner and sells rotary specific products. you will have to sign up, but it is worth it.
http://www.themazdaforum.com/showthread.php?t=773

 

Yup -- the viscosity only determines how fast it ends up on the ground.

 

Well keep in mind that the higher the viscosity, thegreater theoil pressure behind it too, sochances are that it comes out just as fast.

 

It doesn't, fortunately. Once I switched to straight 50-weight racing oil, that did the trick.

 

Mazda says do not use synthetic oil as the oil is used to lubricate the seals and hence has to combust in the combustion cycle. Regular oil will burn and not clog your motor where synthetic oils will not and eventually clog up you motor. I did not have a problem with my original engine in this respect and have not with the re-build that Mazda installed on the re-call over 10000 miles ago.

 

if my RX8 was used or out of warranty even then i don't think i'd risk synthetic oil, but here are some web sites where the issue is argued both ways .... my RX8 runs fine so for me the risk isn't worth the potential cost of voiding my warranty, but the argument goes on. in a year or maybe 15k miles from now i hope those who do it let us know what if any problems they have had, but if the problems show as a plugged or disabled cat converter as some sites have suggested, then how will the switchers know the cause of the effect?


http://www.autoblog.com/2006/08/24/m...call-the-rx-8/

http://rotarynews.com/node/view/439

http://www.teamfc3s.org/main/tips.php#4

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