Two Stroke for a rotary....

[doctorr]

If a guy were to run a pre-mix of two stroke oil to provide some scuff protection in his new rotary engine, which one would be best?

The oil would need great lubricity, as it would be mixed 200:1

There are obviously two basic types - TCW3 and 'air cooled', but absolute chamber cleanliness is my main priority.
Which would be cleanest, 'low ash' or 'with dispersants'?

The engine is obviously water cooled, but does that dictate an 'outboard' type?

How about an ISO-GD rated synth?

Decisions, decisions, it's not easy being a geek.

 

[SteveD2]

The "best" in this situation would probably be Amsoil 100:1, since it's already supposed to be mixed much leaner than any other oil. I use it in my (4 cycle) lawnmower at 100:1.

 

[JohnBrowning]

At 200:1 it is not going to matter much. I am partial to Amsoil and Redline two stroke oil. Even the cheap synthetic that Walmart sells is going to be ok at 200:1. At 200:1 you are basicly putting back into the fuel the natural lubricity agents that should be their but are not thanks to emissions laws.

 

[Hasbeen]

Is this a new RX/8, or a rebuilt earlier model. In either case, you are really not doing your engine a favor, as the extra oil will just make your engine take longer to break in and may cause spark plug fouling, (probibly not at that ratio). especially if you use a synthetic which I would not recommend durring break in. I understand your concern, but i wouldn`t lose sleep over it.

 

[Durrr]

Marvel Mystery Oil, used it in 5 rebuilt 12A, 13A and 13B rotaries ive done. All of them have been running strong. One of the 13B's I helped rebuild was turned into a race motor and ran mystery oil through it for 5 tanks to help the apex seals seat correctly. worked like a charm. Compression was in the upper 7s and with 14lbs of boost, he was pushing close to 315hp at the wheels

 

[goldfinger]

I would have to agree with Durrr. If you just have to use some sort of oil in the fuel why not use something that is made for the application like MMO? It's probably close to the same price if not cheaper.

 

[SteveD2]

MMO is just a 30 weight oil with some solvents in it. Just because it is made for putting in the gas doesn't mean it is better. 2 cycle oil, especially synthetic, which is designed to provide lubrication in the gas will be better. Using MMO would be the same as pouring 10w30 directly into the gas tank.

 

[goldfinger]

quote:

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Originally posted by ZmOz:
MMO is just a 30 weight oil with some solvents in it. Just because it is made for putting in the gas doesn't mean it is better. 2 cycle oil, especially synthetic, which is designed to provide lubrication in the gas will be better. Using MMO would be the same as pouring 10w30 directly into the gas tank.

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I don't have any MMO sitting in front of me, but there's no way it's a 30 weight. 5 maybe.

 

[SteveD2]

quote:

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Originally posted by goldfinger:

quote:

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Originally posted by ZmOz:
MMO is just a 30 weight oil with some solvents in it. Just because it is made for putting in the gas doesn't mean it is better. 2 cycle oil, especially synthetic, which is designed to provide lubrication in the gas will be better. Using MMO would be the same as pouring 10w30 directly into the gas tank.

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I don't have any MMO sitting in front of me, but there's no way it's a 30 weight. 5 maybe.

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30 weight MIXED WITH SOLVENTS. No, the oil itself isn't 30 weight, but that's all it has in it for lubrication.

 

[Leo]

Why not use Lucas UCL? It seems marketed for this application and should do well.

 

[doctorr]

The engine is the new 'Renesis' which is basically a tuned 13B.
Looking at the design, I was struck by the virtual lack of lubrication for the swept rotor area, and definitely unimpressed by the 'engine oil injection system'!
The engine is long since broken in, it's at 10 k miles now.
Is the Lucas UCL up to the job, and clean burning?

 

[Durrr]

actually, the new renesis oil design is far superior to the prior designs of the 13B and 12 series.

Before, it would inject oil directly into the combustion chamber (thats why castrol GTX 20-50 was a necessity) and hope that most of it doesnt burn off to lubricate the rotary housing. In the new design, it does it before the combustion chamber at every 1/3 of a rotation so that the lubricant can actually do what its meant to do, not resist detonation. About the only thing thats similar on a renesis to a 13b is the displacement. everything from exhaust, to intake manifold, to intake valves, plugs, fuel system and even metalurgy has been reworked. The new apex seals are made of carbon fiber/kevlar and have been tested to last to 250,000-300,000 miles, a good 2x the prior engine's life expectancy. This motor is nothing short of amazing with 6 intake ports at full throttle, 6 exhaust ports also at full throttle, dual stage ignition and much lighter rotating assembly.

If your motor is already at 10k, i wouldnt worry about it, just keep running normal oil, but don't run synthetic in this engine, keep it to dino oil. If you like this motor so much and wanna get an old RX-7 and rebuild a 13B/12A, then at your first fill up after rebuliding, put one 16oz can to 8 gallons of gas in the mix, and run it through, then for every fillup after that, put in 16oz to a full tank for the first 1,000 miles. then you're fine. Apex seals will have seated by then.

 

[Leo]

The Lucas UCL is up to the job I reckon. Its good stuff. A number of people on the board use it. I would probably prefer it over 2 stroke oil cos it has agents to help keep the injectors clean etc.

Nice technical background on the Renesis Durrr, but it doesnt change the fact that the RX8 is still IMO, gutless!

 

[Durrr]

quote:

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Originally posted by Leo:
The Lucas UCL is up to the job I reckon. Its good stuff. A number of people on the board use it. I would probably prefer it over 2 stroke oil cos it has agents to help keep the injectors clean etc.

Nice technical background on the Renesis Durrr, but it doesnt change the fact that the RX8 is still IMO, gutless!

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gutless compared to what, a f-1? lol its 2800 lbs and has 231hp, pretty nice HP to weight ratio =P

 

[unDummy]

Any of the TCW3 two stroke oils would work relatively well at the 200:1-300:1 ratio when considering the factory oil injection system.

I like the recommendations of some of the lubing FI cleaners also, since carbon buildup is an issue with poorly maintained/driven rotaries. Lucas, FuelPower, and MMO are some that I know are available in gallon jugs. Others can get expensive with a bottle at every fillup.

MMO/lucasUCL/Redline/......fuel injector cleaners can also be added at each fillup for some additional lubrication.
But, these only provide ?less? lubrication compared to using "oil" in the gas. And, should help keep the engine/injectors...clean.

Redline/Amsoil/insertbrandhere make a bunch of 2 stroke oils.

There are also some very clean burning vegetable/seed oil based 2 stroke oils. Check the local RC hobby shop but avoid gummy castoroil(even though its been improved).

Good luck with your choice. I tend to alternate between brands with my rotary.

 

[JHZR2]

I like the lucas UCL, and it even says in the literature somewhere that its made to replace lubricity thats taken out of fuel.
Pretty cheap in the quart bottles.
Definitely feels like my truck and BMW make more power when its in there, however my gf's acura, mothers plymouth and father's toyota dont feel any different: I think its because of injection design.

But all in all its good stuff and Id reccomend it over 2cycle oils, which are good for mixing in diesel, but Id avoid in gas.

JMH

 

[unDummy]

quote:

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Originally posted by Hasbeen:
Why not use a synthetic, there is a post I`ve been following here in the UOA section on a new RX/8 that seems to be doing well? Mazda RX/8 UOA

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The rotary has multiple oil systems. Besides the typical pump/sump/pressured system, there is also electronic oil injection.
Mazda has been leaning out the oil injection for cleaner emissions. Regardless of what oil is used in the sump, it is beneficial to add oil to the gas for internal engine lubrication.
Mazdas biggest mistake, IMO, is that they chose to used ONE oil sump for both systems since it is easier for the consumer.

 

[Hasbeen]

I know about rotary`s, I have one with 276,000 miles on it. an 87 non turbo. I know a lot of people running synthetics and even though I do not, I see nothing but good involved in using them, as they burn much cleaner and wouldn`t cause the carbon issues common with regular dino oils. I`ve found that using Dello 400 15W-40 solves the carbon issue though because of the detergents in diesel oil.

 

[Durrr]

i'll say it again, DONT USE SYNTHETIC IN ROTARIES. youll regret it, its fine for piston engines though

 

[SteveD2]

quote:

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Originally posted by Durrr:
i'll say it again, DONT USE SYNTHETIC IN ROTARIES. youll regret it, its fine for piston engines though

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And this would be because...?