9BASE3

Never seen it. Who makes it?

RX-Midget

I've been using Amsoil syn 2-stroke oil added to the gas for a little extra protection when running hard. It seems to work fine, but I have not torn the motor down to look...

relisys190

ok, i'm not a guru... nor have i been racing Rotary all my life.. I'm a 19 year old punk kid.. with an FC by the way



And... here's a quick rundown of why NOT to use synthetic in a rotary engine..



The Rotary engine has an oil injection system that injects small amounts of oil into either the intake tract, carb, or rotor housing (depending on year/model). This is needed to lubricate the various internal seals and surfaces.



The injected oil MUST BURN, and must burn clean. The root answer to the question is that not ALL synthetic oils burn, and not ALLof them burn clean.

The ones that do not burn accumulate until they foul the spark plugs.

The ones that do not burn clean can leave residues of various substances (like ash? plastic? non-organic sand?) that accumulate until the spark plugs foul, or a seal sticks -- could be apex seal, side seal, corner seal, or oil control ring. The normal consequence of a stuck seal is an engine tear down.



I have NEVER had a problem with GOOD petroleum based oils. They work fine! They are less expensive than synthetics. (I use Castrol 20-50 GTX). They burn clean, etc. etc.



The problem with answering the original question is that it is NOT a simple yes or no. I DO simplify it to a "NO", but that is because I do NOT know whether the specific brand of synthetic you have in mind will work. AND, if it does not work, how long will it be before the damage shows up, and how bad will the damage be? Maybe it will take 10,000 miles, maybe 50,000 miles?? Maybe the engine will fail due to something unrelated to the oil, and there won't be enough left to determine why the failure happened.

TYSON

This is a good point. It is likely old information, though, similar to the clean burning argument. In my industry some synthetics have been found to attack rubber based seals and cause leaks due to the material softening or hardening. I'm talking about gear oil though, not engine oil. We have one huge case where brand XXXXX changed the formula in a synthetic without telling us and we have some 1500 gear units leaking oil because the seals turned to mush. I will never buy oil for my car from them. Piston engines have rubber lip seals too, so I'm assuming all this has been tested to death. As long as the soft seals in a rotary are made from the same material as the soft seals in a piston engine, we should be OK.



Poly-glycol based synthetics can not be mixed with regular mineral oil, because they cause a chemical reaction and the oil fails. To change from one to another you have to flush all the oil and fill with the new. Hydrocarbon based synthetic can be mixed. I would assume engine oil is hydrocarbon based, because they would get too many failures and you would have to use poly-glycol right from new.



Amsoil offers a preffered customer deal where you can buy oil from them for wholesale prices. I am going to try them, since they carry a full line from synthetic motor oil to synthetic 2-stroke for pre-mix to synthetic tranny and diff oil.



Please keep in mind that the whole lubricating oil industry is very competitive, and frankly a lot of them lie through their teeth. Brand XXXXX above refuses to admit they changed the formula in their oil, yet it is a completely different colour than it used to be.

Tom93R1

Current synthetics all burn, and most of them burn more cleanly than the non-synthetics. Their flash points are well below what the temperature inside the combustion chamber reaches. The notable exception I have found is Valvoline synthetic, while it does indeed burn its ash content is actually higher than the Valvoline non-synthetics. Mobile1, Royal Purple, Amsoil all burn with a very low ash. This information can be found fairly easily with a web search on google.

9BASE3

Current synthetics all burn, and most of them burn more cleanly than the non-synthetics. Their flash points are well below what the temperature inside the combustion chamber reaches. The notable exception I have found is Valvoline synthetic, while it does indeed burn its ash content is actually higher than the Valvoline non-synthetics. Mobile1, Royal Purple, Amsoil all burn with a very low ash. This information can be found fairly easily with a web search on google. [/quote]

Great info!!

Striker

would there be any advantage to mixing(50/50) dino and synthetic, and would it harm the engine?

has anyone seen a tear down of an engine that has run synthetic its whole life? what did it look like? was it an oil related failure?

lastly, what is a good brand(not really expensive) and weight for warmer canada.

relisys190

Man, this Debate is so ongoing. Basically this is the way i see it. The Rotary engine was designed to run on standard mineral oil. Synthetic oil they tested back in the 80's had ash deposits.. and would gunk up your housings and ports. Sure synthetics nowadays are much more advanced. BUT if Mazda doesnt recommend using synthetics, than Dont.





I've used Castrol 20-50 for almost 2 years, and i swear by it. Never would i use Synthetic in my engine. UNLESS- - I was running a very large turbo, demanding alot of oil cooling... and OR, Had alot of internal engine mods done. Otherwise Standard Mineral Oil of any kind will do fine.



Guys I'm not a race car driver. I am not running on the city streets at 9000 or 10000 RPMS Constantly...

I am however a rotary fanatic. Making sure my car runs perfectly, every time i start her. sure i take her up and buzz her a couple times a day. but the engine is not a race engine. it does not need Synthetic.





I think that's all i have to say.

RB180sx

kind of off topic but how does the oil lubricate the rotors? i mean the apex seals dont just rub up against the combustion chamber un-lubed right? or do they? maybe if someone has a picture of where the oil DOES go in the rotories, just a little confused. I can see the eccentric shaft being lubed b/c it seems sealed from the CC. thanks alot!

motoracer47

first just want to say, im not claiming this to be fact, just my 2cents.

I have a thought as to 1. why mazda does not recomend synthetics, and 2. why rotary engines consume synthetics faster. I think we have established that synthetics for the same weight are a less viscous fluid, and with the properties of synthetics, you can run even a lower weight syn than you could dino. Back when the oil systems for these engines were designed, the predominant oil was dino, so mazda designed their oil injection system for dino. Logically, if you run a lower viscosity oil in your engine, specially one that (for lack of a better term)is more slippery(less surface tension?), would it not stand to reason that the oil metering system cannot compensate for this and will ultimatly inject too much oil into the housings? If so, then this would proly explain1. oil consumption2. the fact that rotary engines would have gotten a very bad rep for eating oil(maybe why mazda said not to use it)3. and this may also explain why some people have reported spark plug fouling and leaving deposits on the rotors(though thats proly from the ash content of OLD synthetic oils). My opion is that synthetics will in no way harm a rotary, you might however want to test how much is going into the engine though.