Auto RX Maintenance in Rotary Engine

[digitalSniperX1]

Ok, I mistakenly posted this in the PMCO area and have moved here which I think is more appropriate. My apologies

My car is of course, a Mazda; specifically it's an RX8. The rotary engines are known as oil burners quite simply because they do so by design. Then engine has a computer controlled pump (oil metering pump or OMP) that injects oil onto the rotor apex seal surfaces and the volume injected is based upon driving conditions and temperature. Hard driving one could burn a quart in < 1000 miles. Normal driving, a quart in 3,000 miles.

Mazda recommends agains using synthetics in these rotaries, so I use Amsoil's XL 5w30 (in summer) and 5W-20 in all other seasons. Others use synthetics with no reported issues.

One modification many enthusiasts do to these cars is install a bypass adapter to the OMP and supply 2cycle oil to the engine from an underhood mounted reservoir. I've not made that modification but I'm considering it.

Another thing rotary enthusiasts often do is put 4-8 oz of 2 cycle oil in the gasoline tank. In fact, Idemitsu makes a 2cycle oil specifically for this purpose. I use Amsoils Saber Pro as it has the same or better ratings than the Idemitsu product. I also use FP+ mixed with the 2 cycle. I run about 5 1/2 oz of that mixture per 12.5 gallons of gasoline.

The designed in oil burning causes issues with the rotary apex seal springa (the seals and springs are the rotary's equiv to piston rings) in that carbon formation, there and in the exhaust ports, occurs over time.

My questions are....if I install the OMP bypass adapter, would it be safe to mix in very small doses or Auto-RX to help combat the carbon build up?

If I don't install this, would using maintenance doses in the oil pan along the the Amsoil-XL be helpful in reducing this carbon buildup?

I'm sure this isn't an easy question to answer, so it'll probably involve opinions, which too are welcomed.

 

[Quest]

http://www.bobistheoilguy.com/forums/ubb...377#Post1172377

Just like Frank's against the use of AutoRx in 2cyl engine (to burn with 2T oil), I'm against the use of AutoRx in your oil for it doesn't get the job done before it get's burned, and that may make things worse.

If you want something seriously performance for your rotary engine, try doing searches on the subject on Rotary engine in Japan, and see if you can get those rotary blend motor oil.

Q.

 

[digitalSniperX1]

"I'm against the use of AutoRx in your oil for it doesn't get the job done before it get's burned, and that may make things worse."

This is exactly what I was afraid of....although the oil is injected early with respect to combustion in the rotation cycle, i.e. I think just after combustion occurs, the oil is injected into the engine.

As per the warnings from Mazda in your other threads...the Idemitsu product is a full synthetic and recommended for rotaries. Also, the 5W-20 recommended by Mazda would include GRPIII oils, often called synthetics...so the recommended non-use of synthetics in the rotary is a blurry one. I'll stick with the Amsoil XL series here, which in a way straddles the fence on the synthetic/non-synthetic debate for this engine.

 

[Quest]

"synthetic" is just a calling, not a "be-all, end-all" terminalogy and no 2 "synthetic" oil are of the very same nature, due to the blend and it's intended usage.

For example: there are some synthetic 2-cycle premix oil (such as Mobil MX2T) that not only can take the heat but also burns extremely clean.

You simply cannot infer that Dexelia will be/shall be just like what you would get here like other so-called boutique synthetic motor oil(s) destined for use in regular 4-cycle reciprocating engine designs.

I would suggest you to stick with Dexelia if I were you, even if it burns 1qt per 1000miles.

Q.

 

[digitalSniperX1]

Well sure they are different...and I wouldn't assume otherwise.

I don't think the Dexelia product is available in the US. Mazda does sell their own brand, but I think it may be Mobil Clean 5000 in a bottle with a Mazda label on it, not sure though. I am sure it's not specifically for the RX8.

I will look for it though (the Dexelia)


Thanks for the information.

 

[Quest]

Unless you have proof that Mazda badged motor oil in your dealership destined for use in Rotary engine is, in fact, Mobil driveclean, otherwise, don't "assume".

When in doubt, do some serious research and weed out all the possible "noise" on the internet. Currently, I'm highly aware of the fact that Dexelia does burn clean and it's well suited for rotary engine. DO NOT, I repeat, DO NOT assume that 4-cyl reciprocating engine oil would work properly on rotary, otherwise, the damage is yours and not mine.

Take care,

Q.

 

[digitalSniperX1]

I intend to bring this up to a few guys at my Mazda dealer who own RX8's and RX7's. They may know how to get Dexelia. I know it was developed by ELF with Mazda's input.

I do not understand why it's not readily available to US customers. If in fact it helps with the carbon buildup issues, then they it should be made available, and in fact highly recommended to RX8 owners.

These engines have been problematic, esp the 2004 automatic models. I don't know the statistics, but engine replacement seems to be much higher with these cars than with others.

It seems that if Dexelia is the silver bullet that cures the carbon builup issue, it would be in Mazda's best interest to make this product available at an affordable price here in the US.

I've seen it on the internet for sale from the UK at 8 british pounds per liter. That'd be 16 US dollars plus shipping.

I think I'd go the route of supplying 2cycle oil to the OMP before spending that kind of money on sump oil. I change the oil pretty often (