There has been a lot of debate concerning which type of engine oils should
be used in Rotary Engines, and, I believe the large number of Engine failures
in the US this summer are attributed to the engine oil type and
more particular the grade.

Firstly, I would NEVER recommend the use of Synthetic oils
or additives in the sump for any type of Rotary, Renisis or earlier models.
Regardless of what some Service Managers suggest at your local dealer.

Many of these synthetic oils have a heat weighted rating of 0W20,5W30.
While brand new they perform OK, however their "thinness" lightness
is fine for cold weather between 0 Degrees Celsius, and 30 Celsius, around
90 F., they are way too thin to protect when you have 110 F degrees
plus in Texas and Nevada. You have NO engine wear protection, the engine oil
would be as thin as WATER!
In these extreme high air temperatures you should be using a grade of 15W40/50,
many techs would say that these are too heavy, but this is exactly what you want.
Protection under severe heat.

Most engine oils after a few thousand miles loose much of their viscosity, check
your dipstick when cold and rub the oil between thumb and fore finger, and then
compare it to new oil in your garage/basement.

I would only use light oils in Winter and heavier oils for Summer.

Servicing dealers don't usually change their stocks for climate change, they use the multigrade 5W20/30 or 0W20 which is far too light in hot weather.

I believe many of these engine failure could have been avoided, and time may discover that the oil grade used by owners and dealers has a lot to do with it.

 

Sorry, Not sure exactly where (AZ) is, I asume its Arozona?
What are your minimum/maximum temperatures.
Example:
A 5W20 oil has a min viscosity for 5 degees(C) or your about 42 F. With a MAX 20 Celcius or
70 F.
And this where the problem appears, most of you guys are ussing oils that have a max rating of between 20 and 30 Celcius thats 70 and 86 F.
Areas in Texas and Nevada have had temps of 115 F or 46 Celcius.
Which is way too hot for the thin oils many are using in summer.
Someones head should roll for recommending a 5w20 or 5W30 oil, they should be using a
15/20W40/50.
Hope this helps

 

So, to put it more easily...its....

Lower grade THINNER Viscosity (0W20/30) for WINTER .....COLD!

Higher grade THICKER Viscosity (15W40/50) for SUMMER...... HEAT!

 

Average temperatures in Phoenix, Arizona
Average temperatures in Sacramento, California
Average temperatures in Las Vegas, Nevada
Average temperatures in Houston, Texas

You can determine the average temperatures just about any city in the world:

 

Ash, really, stick to your day job. Don't go making rash statements such as "You have no engine wear protection.....", that's just alarmist. If you have facts, back them up. If you have opinions, say "In my opinion.....".

 

Well you shifty bastard, how much wear protection would you suggest when you use an oil that has a max temp rating of 20 celcius, and your driving around weeks on end at 46 celcius outside air temp. (Texas)

I say or make whatever statement I wish...alarmist no, facts, you prove me wrong!

 

Ash8

I feel you make very valid point regarding the oil , even of greater concern to us Aussie drivers is the fact that we only have the 1 oil cooler in our cars , if the American cars are showing engine problems due to heat with their 2 oil coolers we really have a POSSIBLE potential problem Dowunder


As we know the oil accounts for up to 30%of the rotaries cooling of the engine

I complained to Mazda Australia about the lack of a second oil cooler they had the adacity to tell me that we dont need the extra oil cooler because we have different weather to the USA , what a lot of BS , THE REASON THEY NEVER GAVE US A SECOND OIL COOLER WAS PURELY A COST CUTTING EXERCISE

I am currently sourcing and will be fitting a second oil cooler to my car i believe this to be an absolute necessity especially if you are in a hot weather enviroment or you are considering forced induction .

B...free
michael

 

If you use the standard second cooler (US spec) you still have no real airflow when the car is stopped and at idle.

Why doesn't someone try and install a cooler in front of the radiator? I read somewhere that the second gen Rx-7s had this.

 

The numerals in the oil viscosity ratings do not indicate minimum and maximum temperature ratings.
Visit the following site for insight:

http://theoildrop.server101.com

Specifically, this thread should help:

http://theoildrop.server101.com/ubb/...=000002#000000

 

you do realize that the US cars are required to run 5W20 if you want to keep your warranty?

You should also realize that synthetic viscocity drops off much less with temperature then conventional oil, has far greater resistance to thermal breakdown, and much greater resistance to thinning from gasoline over time

 

you should really spend some time reading about how oil viscocities are defined... its not even close to what you believe

 

This sounds like a good idea. With the stock oil coolers, unless the car is moving, there is no air flow over the oil coolers. This in reality means that it makes little difference at rest wether or not there are two oil coolers or only one..........

If we could have an oil cooler that had airflow over it at rest from the cooling fans....and the fans were re-programmed to be on a lot more than they are now ( https://www.rx8club.com/showpost.php...&postcount=251), that should result in much cooler engines...and less potential for heat related failures. If this is what is going on in the AT's in hot climates????????

 

So why does mazda tell us to run the mazda mineral oil 5w20 on the rotary as opposed to the synthetic

B...free
michael

 

I quess If they dictate the rules...then they have to pay.......

 

For starters Michael, Mazda Australia do not limit us to 5W-20. We in Australia can pick from a huge range....refer to the page below. Refer also to the Parts Bulletin I have put up here a number of times over the last 18 months regarding the Synthetic/Dino oil debate.....

 

speed source racing runs a 20/50 oil in their rx8's. Stock engines. I think. I have run a 10/30 befoer and the engine was quieter.
olddragger

 

its more of a political thing then anything else - for an oil company to get their oil specifically approved for an engine, they have to pay big $...

like mobil is willing to pay big $ to get their products approved and get a logo on the oil caps of vettes,bmws, mecedes, ect because of a marketing plan in associating their oil with the best, but they aren't willing to spend big $ for a specific engine that only a couple tens of thousand are produced a year

then on the other side, most auto companies believe that synthetic is not truely necessary and can save them money by not using them - so they don't spend their money to have synthetics tested and approved either.

 

These debates already happened a few years ago...when everyone thought 30 wt oils were too thin, and that "your engines are going to self deontate on the thin oils". Now 30 wt oils are accepted, and everyone freaks out about 20 wts. The same thing will happen in a few more years when we move to 10wt and 5wt oils. Everyone will think 20 wt's are awesome, and argue and yell that 10wt and 5wt oils are going to destroy your engine.

Most of the literature you read on 20 wt oils is old and outdated. It no longer applies to current specs or technology levels.

As already mentioned, you can visit http://www.bobistheoilguy.com for more information on how current oils are performing vs their old counterparts.

Viscosity is not a measure of protection! Its just a consumer label to aid in picking the correct oil for your car. There are so many other specifications that determine the oils relative strength under stressful conditions which aren't revealed by just glancing at viscosity levels.

Arguing over viscosity #'s is like arguing over which engine is better based on its weight...without knowing anything about the type, size, displacement, or power output of that engine.

As for cross-country specifications...this comes down to supply as much as temp ranges. There just ISN'T any 20 wt oils available in certain countries...AT ALL. For example, in southern america, if the Mazda 6 owners want 20 wt oils, they have to IMPORT them. Surprisingly enough, even in such hot and humid climates, the 20wt oils are showing equal or BETTER wear #'s then 10w-30 or heavier weight oils in UOA's (used oil analysis).

To give you an idea of how far 20 wt oils have come...check out some of the ferrari owners running 0w-20 mobil1 in their 575M's. (15w40 recommended).

 

I thought it stemmed from people doing rebuilds on 7's finding little ***** of unburned synthetic oil in the engines they worked on.

 

Why not use an 'oil cooler fan' (similar to what is used for the radiator) for each oil cooler (two for the M/T cars, one of the A/T's)? This would certainly dissapate some of the heat from the oil supply.

 

Hey Gomez, what do MC and MA stand for (from the text in the memos)?

 

michael most of the failures (@90 ou of 100) were on AT cars which only have 1 oil cooler here.

 

As I just wrote in a different thread, the High Temperature/High Shear viscosity for RedLine motor oil is extremely high, even in the 5w-20 variety. It's quite a bit higher than even other synthetics such as Mobile1 5w-30, which I know people run.

I wonder if this is a number worth focusing on.

Obviously, the rotory is a different beast, but the stuff works great in piston engines, at least.

Here's some propaganda, but you might find lots more on BobIsTheOilGuy.com:
http://www.drivetrain.com/redline.html
http://www.allsyntheticsgroup.com/ar...i-compare.html

Perhaps someone in Vegas could try RedLine oil as an additive, at the very least. The only thing it could hurt is the pocketbook- it's $9/quart!

 

Stretch, you seem to be confused. The HTHS test is valid within the same oil grade. For the same brand, if you change from W20 to W30, the HTHS will be worse. But, your engine will be better protected by W30. And I mean by viscosity, not by the huge load of chemical additives the Redline or Amsoil probably use (based on the results at those links). Why? Because lets say your W20 has original vis 4cP and it looses 0% (perfect HTMS). Used, it is still a W20 oil. The W30 has to have original vis 6cP but is worst, it looses 30% vis in HTHS. When used, it is 4cP. But before is gone, it did prvode higher vis, did it not? So how is the W20 superior in this test to any W30? It is not. The second criteria to pass HTHS is not to drop more than an oil grade after the test. So the absolute worst ever W30 oil will be, when broken down at the end of its life, at least equal if not better than the best W20. Ask Bob the oil guy
Second thing, are Amsoil or Redline API certified? Never used them so I have no idea, but I guess that at least one of them will not be. Why? Cause to get those test results, they are like athletes on steroids. How come? Because they use, at best, the best components for oils that are out there - just like everybody else. So how can they be better when they do not make anything by themselves but buy stuff from others and just blend? Put more additive. Sure, you get some tests to pass with flying colors. But, you will not get all of them to even pass - hence, the Mobil 1 is API certified and used by car manufacturers - so they kept it real. The racing oils above are great in the tests you've shown - but when you put them in a regular car, the large amount of additives will destroy your catalyst (and YOU'll pay for a new one) and, on the oil-injected Renesis, build-up deposits inside the chambers. Now show me the ash contents on all those oils if you want to win this bet ;o) So unless you have a race car (no cat, will rebuilt engine once a year), I wish you good luck with the racing oils. 'Cause you'll need it ;o) Talking about hurting the pocket......