Can a rotary use synthetic nowadays?

[ourfamo4]

I hope someone can give me a straight answer.

My friend has a low milage 88 Rx7 non-turbo. 2 rotor. The owner's manual says specifically not to use synthetic oil.

But since that was 88 almost 20 years ago does it apply? On the RX7 boards some say yes some say no. I trust the people on here alot more than a bunch of kids with 4inch ehaust

The car now has 27k and is getting alot more use now than ever. He is now running GTX 10w30, which is what the PO did. Whould 5k OCI on synthetic be possible? Thanks for any info.

 

[LarryL]

Someone in the shop went through two engines in his RX8 using dealer service and oil, which was dyno oil. On the third engine he switched to synthetic and now has more time on that engine than the first two combined, so far. Warranty covered the problems but it's still a pain going through stuff like that. He picked his oil based on surfing the web and talking to other Mazda owners at some Solo racing events. His choice was Royal Purple after talking to the people at Racing Beat, 10w-40.

 

[Drew]

Its a waste of money on an RX7 non-turbo.

Rationale: 13Bs run pig rich and fuel dilution limits your oil change intervals to 3,000 miles.

I'm on my 4th RX7 and my 91 Vert currently has about 26,000 miles on it. I personally run 10w-40 in the summertime and 5w-40 Rotella in cooler weather. 10w30 isn't a good weight in the summertime. In fact, most people run 20w-50 year round.

Don't forget, add about 1/2 of two stroke oil per gallon of gas next time you refuel. Your apex seals and housing will love you and you'll get a longer lasting engine. If you disconnect your oil metering pump, 1-1.5 oz of two stroke oil per gallon of gas should suffice.

[ January 10, 2006, 02:12 AM: Message edited by: Drew ]

 

[audi_guy]

I saw somewhere on this board a link to some Japanese oil that has a oil specifically for the rotary. Don't recall the name, whether it was synthetic, or what made it good for a rotary. I don't remember where I found the link but they had a 0w30 which lead me to it. Could have been the GC forum.

 

[AndyH]

Royal Purple covers this in their FAQ, they say synthetic oil is fine for use in the rotary engine.
http://www.royalpurple.com/techa/faqsa.html#re0

 

[unDummy]

Rotary engines could ALWAYS use synthetic.
If money isn't an issue and you want the best, go for it.
But, I would ALWAYS change the oil within 3k miles or 3mo.
Don't use ANY oil as an excuse not to practice a frequent OCI, due to the above mentioned fuel dilution and the fact that you want to inject clean oil for lubrication.

 

[ourfamo4]

Drew, is this 1/2 oz. of 2 stroke going to trip the CEL, or hurt the cats? So it sounds like Rotella T blend year round at 3k OCI.

 

[JAG]

Mazda has put out the following information that I will try to paraphrase here. It's on the internet too if you want to see it straight from the horse's mouth and see if I made any mistakes.
1. The RX-7's engine seals are NOT fully compatible with synthetic oils. They are made of "old-school" material. My quotes, not theirs.
2. The RX-8's engine seals are of a type that is fully compatible with synthetic oils, but Mazda did not do sufficient testing of synthetic oils in the RX-8 during development for them to officialy recommend synthetics in this engine. Basically, they chose this seal material to be on the safe side, knowing that some owners will use synthetic, but did this engine's developmental testing using mineral oils. My comment: I'd be comfortable trying synthetics in the RX-8 engine.

 

[unDummy]

Which engine seals aren't compatible? what old school material? Sounds like more Mazda bu!l to me straight from the horses arse.
And, the word synthetic hasn't even been defined buy any technical group or by Mazda yet, has it?

2-stroke oil won't trip a CEL and won't hurt the catalytics. If anything, IMO, you would be smart to dump the motor oil injection for full premix for longer lasting engine and emission components. If emission testing isn't an issue, I'd dump the cats for a little more power and reliability since they are nothing but an exhaust cork.

 

[JAG]

I don't what know what seal material the RX-7 uses. Just relaying what they said. I'm confident that this isn't something the marketing dept. decided to come up with to mislead people for kicks. If you do what a company recommends against, it might work out, but it is a science experiment with your engine at risk.

 

[GT Mike]

This takes me back. I used to race an older RX-7 with the 12A engine. From what Hayes Rotary Engineering (wonder if they're still in business?) and Racing Beat told me, synthetics were to be avoided due to the metering pump piddling oil into the carb that it would foul out spark plugs. I ran M1 15W50 in mine, and did notice some wierd glazing on the plugs. I switched it to Kendall GT-1 20W50 and the plug glazing went away. Hayes recommended Bardahl Engine Oil Supplement #1 with every oil change, but to this day I've never found this product, or found out what else would have been comparable.
I also did the 2-stroke oil in the gasoline trick, though sometimes I added a little too much, and it smoked like a weed eater. With a header, no cat, and 2.5" exhaust it sounded like one too!

I did run high 15s with it at the track though...Not too shabby for a mere 70 cubic inches!

 

[Solo2driver]

I pick up my Series 5 13B freshened engine (well, new rotor housings, rotors, repaired side housings, all new seals...could just call it a new engine!). The original plan and at the recommendation of the engine builder due to his specs on the motor was to run Lubrication Engineering (www.LE-Inc.com) 5w30 conventional oil. Royal Purple Racing 21 or Idemitsu 10w30 would also be acceptable, and I plan on using ProTek-R (Klotz R-50 in different packaging) as pre-mix. UOA every 3K with changes and I'll post them online, this particular build is only expected to last 35-40K miles before smoking as we were liberal with the engine tolerances for racing (still not ported, though), I hope to extend the life a bit longer if I can

 

[Drew]

No, the 1/2-1 oz of 2 stroke oil per gallon of gas in the tank won't hurt a thing and will greatly extend your engine life. In fact, many people disconnect their oil metering pump because it injects dirtier, less cleaner burning oil from the oil pan.

 

[Drew]

No need to waste your money on AMSOIL. I use Supertech TCWIII 2 stroke in mine-it loves it. I had bought a bunch of Penzoil 2 stroke and it actually settled in my fuel tank and gave me a very healty smoke screen each morning. Supertech doesn't.

 

[ourfamo4]

Thanks for all the help guys. I think he's going to run Rotella 5w-40 for the winter and M1 15w-50 in the summer. I picked some old SL M1 15w50 at K-Mart yesterday on clearance for 3.99 a quart. So we'll see how it goes. Also just use any 2-stroke mix like the havoline I use in weed eater? Or order some Amsoil 100:1 ?

 

[GT Mike]

I always used to get rid of the previous season's Lawn-Boy gas in my RX-7. They smoke real good running on 32:1!

Well, probably more like 50:1 since the tank wasn't completely dry when I dumped it in.

 

[Solo2driver]

I may need to use some Supertech for pre-mix as an emergency as I've had trouble tracking down the stuff I was planning on using. With the OMP connected I've been told to use only 4oz per tank (18.5 gallons in the GTUs).

 

[Tanjo]

Well, as a lot of us know, rotarys pump oil into the combustion chambers directly from the crankcase, and it was always my understanding that the reason that a lot of us rotary guys dont use synth is because it doesnt burn as cleanly as standard oil does. And the reason we change our oil really frequently is because we pump the oil into the combustion chambers, and through the turbo, and we dont want any crud messing with the apexs and other seals or doing bad things with the turbo. ****, I changed my oil every 2K or so, and premixed with MMO. I had 190K miles, and that thing still ripped

 

[bobo]

I have an 85 GSL-SE with the 13B engine and typically run Castrol GTX 10w30 oil with about a 4K OCI. I add a litre of oil just after half way through the OCI and have never used a 2-stroke mix.

The car has 125K on the clock and runs like new.

I wouldn't consider switching to synthetic oil for a 13B engine.

This is the first I have heard about fuel dilution in engine oil for a rotary.

 

[daisuke]

fuel dilution is what you get when you shut the engine down before it warms up, if it floods itself you need to change your oil right away for that reason.