Using oils designed for diesels in gas engines

[digitalSniperX1]

Good information Doug. I think the clean burning issue is the major issue.

Some do say the eccentric shaft is not propery lubed with 20weight and that 20weight will not develop enough oil pressure at high RPM to protect it and associated gears.


It's interesting to note, the engine burns very little oil when driven normally. When driven agressively, oil consumption as well as exhaust pipe soot increases significantly. I've also noticed less soot in the tailpipe when running the premix.

None of this is scientific of course and I've only been doing it for a short period; so my sample size is very small.

In the long run, I'm expecting to simply run the 5-20 with perhaps 5-30 in the summer and it'll most likely be Pennzoil.

Unless there is a cat converter issue using the premix that I can't tolerate, then I'll probably stop that also...even if recommended by rotary experts here in the US.

Mazda does sell oil for mixing with gasoline in rotary powered cars however I'm not sure they offer it as a supplement for their OMP in a daily driver or if it's just to be used in racing applications. I'll have to look into it and see.

 

[Doug Hillary]

Hi,
digitalSniperX1 - The shaft issue and 0w-20 may be just a "fairy tale" - ther are many around
As lubricant consumption is based on fuel use expect to put more in the lubricant's tank if you drive it hard

Many moderm Pre-Mix 2 cycle lubricants are clean buring and smokeless and could be beneficial in a very small volume.
I use it too from time to time in my Porsche - I use FUCHS "Silkolene" Pro KR2 "2T"
As this is a castor & ester based synthetic the exhaust odour is just sublime. I use it at 1/4 of the recommended minimum dose on the label

 

[JohnBrowning]

Usualy a HDDEO has more ZDDP,Calcium,Phos and higher HTHS. Their can also be more of other additives as well. So you have a solid HTHS and a solid Additive package. Now some like Delvac will be changing their additive package soon but no matter what they do it will handle soot, high loads and heat better then most PCMO's do!

 

[Avelectro]

I also have a 2007 RX-8 with about 5000 miles and I am using Mobil 1 15W-50. A VOA is at this link: https://bobistheoilguy.com/forums/threads/new-mobil-1-15w-50-voa.80688/

I chose this heavyweight for a few reasons: 1) my location has high ambient temps, Phoenix, AZ; 2) a very informative thread on the RX8 forum, RX8Club.com, gave emperical evidence that higher viscosity oils working in high ambient temps actually gave lower oil operating temperatures; 3) scary photos of engine teardowns after using the (for the U.S.) recommended 5W-20 oil; 4) This engine has a reputation for fuel dilution; 5) I think the Wankel motor is a high HTHS engine that could use the above average ZDDP of the Mobil 1 15W-50.

Now I am questioning whether the RX-8 motor needs this additive package and perhaps an SM oil would be wiser in order to avoid the dreaded apex seal and side compression seal jamming caused by combustion deposits? To help alleviate this I have been adding 8 oz of Marvel Mystery Oil to each 12 gallon fuel fill.

 

[digitalSniperX1]

Hello Avelectro,


The RX8CLUB site is a good source of information since there are several there who really have a lot of experience with this engine.

Having said that, several of them race these cars and their recommendations are based on the fact they do that, including the heavier oils.

I do intend to install the Sohn oil adapter. I'm betting this helps extend the life of the apex seals and reduces the carbon deposits. I don't think they'd be doing this in aircraft engines if it weren't true.

While I'm waiting to do that, I intend to learn as much as I can. I don't have 1/2 a day to put it on now. While waiting I'm using Amsoil Saber Pro and FP+ in the gasoline tank. 4oz of the 2 cycle, 1.5 oz of FP+.

After reading as much as I can on the suject of oil, I'm nearly convinced the best value/performer in oil is Pennzoil's Platinum brand of oil. I think I'll simply run 5w30. I drive highway almost exclusively and don't do much stop and go. It's also a grpIII oil and almost all 5-20's have it in there, so that gets me past the advice against using synthetics since mazda does not recommend them.

Plus, I can use pennzoil in my Acura RDX. Two cars and one oil makes it a bit easier to stock (although I have 18 qts. of Amsoil's XL oil, which is good also).

Of course all this is a hunch but I'm using a collection of information to try to come up with the best combination for my driving.

Lastly, I think with this rotary engine, engine failure is a matter of when, not if.

One thing positive when it dies...that'll be the point I go to a turbo charged engine.

 

[Greaser]

Originally Posted By: digitalSniperX1
Originally Posted By: Greaser
Been using HDEO for years on my gassers with great results.I have the used oil analysis to back my claims.


Why did you begin using them over the PMCO's?
Better protection less cost than "run to the mill" PCMO.

 

[gtx510]

http://www.mobiloil.com/USA-English/MotorOil/Files/Mobil_1_Product_Guide.pdf
Mobil Delvac 1 5w40 / Mobil 1 Turbo Diesel Truck 5w40 is SM/SL.
Rotaries burn oil...
One of the high mileage oils or 5W40 ESP might be a better choice?

 

[TallPaul]

Diesel oil is fine for gasoline engines, so long as it has the gasoline engine "S" rating (SL, SM, etc.). Problem is that most of these HD oils are hard to find in 10w30. Usually it's 15w40. Murrays sells Motorcraft diesel/gasoline rated oil in 10w30 quarts.

Another option is Valvoline VR1 racing oil, which has HD levels of zddp and comes in 10w30.

 

[ThirdeYe]

TallPaul - Menards carries Rotella T 10w30. I was tempted to try some in my Integra. I do worry about the catalytic converter though, with all of the extra additives. I don't think I have to worry though, since my car doesn't burn oil.