I wouldn't use 10w-30 in this engine, synthetic or otherwise. A higher viscosity is required to account for the thinning effects of fuel dilution. As Blackstone indicated, it's probably not a good idea ot use anything lower than 20w-50 in summer and 10w-40 in winter. If your winters are mild, you might try a full synthetic 20w-50 with a low pour point. Unless you regularly take short trips, any minor start-up wear with a higher viscosity oil is quickly offset by bearing wear if you drive the car hard.

Yep...but get it tested.

As you can see from my Blackstone reports, lower viscosity oils do not adequately protect the bearings.

Oil in these motors breaks down within a few hundred miles, so you may as well just use a heavier weight oil and plan on it happening. In most cases, synthetics are only worth the extra money for long drain intervals or racing applications.

 

Interesting I had been using 10w-40 thinking the 20w-50 was too thick but might switch back now.

What kind of temperatures do they consider it being summer / winter? We don't see temps go much higher than 30C in the summer here so maybe the 10w-40 is fine.

 

I'd say anything above 40 F/4 C is fine for 20w-50, but you might want to use a synthetic if you regularly drive in those temps.

It's surprising how well 50-60w flows in summer temps, and these engines don't take long to get up to temp. I believe cold start wear is overrated in a rotary, more damage is caused at peak operating temps because of watery, gas diluted "10w-30". Go pull your dipstick and watch that pitch black oil flow off of it like water, you know what I'm talking about if you own an FD.

By contrast, the Amsoil 10w-30 in my S2000 still has a honey gold color after 5000 miles of hard use.

 

Finally got my oil report!!!

Pretty happy to see the results.

Although not really happy that my numbers @ 1000 miles are almost identical to average numbers @ 3500 miles.

But obviously each engine is different.


Oil was removed @ exactly 972 miles. Castrol gtx 10w-30.

My question is should i be happy with the water/antifreeze %?? Does that mean my coolant seals are still holding up strong since no water was found in the oil???

No more rice, where are you?? Help me buddy!!! lol

 

Wow, that report looks really good! Your fuel dilution is basically nothing and the viscosity pretty much stayed in grade. Tell us more about the motor....

 

Well remember i did pull the oil at 1000 miles.

Although normally i would have changed it somewhere around 1500 if i stayed within the 3 month period but i was so anxious to get the oil tested, i pulled it.

Blackstone suggested i could run my oil a bit longer but also said if i want to compare oils, i should pull my current oil again at 1000 miles. Right now theres RP 10w-30 in there w/RP premix.

So thats what ill do, then compare. Then decide what oil and how long should i be doing oil changes.

 

To see that low of fuel dilution in a turbo rotary you must be staying off the boost for the most part. I think the only way I could get my fuel #s that low is cruise down the highway at 15s/16s AFR for a few hundred miles. Is this a rebuilt motor?

 

You're a smart man.

Yes i do ALOT of highway driving now. And i rarely get into boost. Probably 3 WOT pulls at most during each drive. Usually i just like to cruise, i dont like the idea of boosting constantly in these summer months.

No its not a rebuilt engine, well actually i dont know. The guy i bought my car from is/was a mazda mechanic/engine builder. He told me he "rebuilt" it sometime in the past for durability. But there was no record of that. Although he did give me a 6 month on paper warranty for the engine at the time i bought the car. So maybe it was rebuilt otherwise i dont think he'll give me a 6 month warranty on a used car with the original engine to a kid since i was alot younger a the time lol

Exactly how healthy is my engine in your opinion??

Would you say my coolant seals are strong because there was no water found in the oil??

What do the other numbers mean? Like zinc#? etc?

 

an interesting thread.

from the oil analysis numbers you'd think that rotaries would be having bearing and stationary gear problems and they most assuredly are not.


generally rotaries i take apart have re-useable bearings and stationary gears. so if the oil is all diluted how come no bearing problems?

i do understand that generally oil in rotaries is really ratty. lots and lots of carbon and some fuel.

i run nothing (ever) but Mobil One 5-30. w my oil system i have 80 pounds of oil pressure at 8000 rpm. 55 pounds warm at highway cruise around 145 F measured in the oilpan.

w 80 pounds at 8000 i wouldn't dream of running a heavier oil.

the reason i run Mobil One is twofold, i was sponsored by them for 6 years and everything worked great and my friend Jose Le Duc told me to run it and run nothing else. i listen to Jose. he has never steered me wrong. he runs/designed/built a 1000+ rwhp 2 rotor 2000 pound RX3 drag car that has run in the low 7.50s at over 185.

i listen when Jose speaks and he was emphatic. look it up.

i also run 4 oz of ZDDP+ w every oil change.

i really don't get the fuel smell from my oil but i haven't yet tested it. maybe later this year.

personally i think build quality and tune rule as to fuel in the oil.

hc

 

Although uncommon, bearing failures do occur, Rich had mentioned this issue on another thread

Perhaps rotary engines are easier on bearings in general?

You should get it tested and see how that 5w-30 holds up after 2000 miles (or whatever oil change interval you're using)

Is > 80 psi unacceptable? No problems for me so far, I'm running straight 60 weight.

Mobil 1 EP is a great oil, standard Mobil 1 is just ok - it doesn't perform as well as Amsoil and some of the others in wear tests or UOAs I've seen

I honestly hope you're right, but I'd like to see the proof. As rich as these motors run at full boost, some fuel dilution seems inevitable.

 

Freeway cruising isn't that useful relative to this thread because your fuel dilution will be low when you're rarely boosting (most of your time is spent above 14/15s AFR). I wouldn't even bother posting it. I want to see reports from people like me who drive the car HARD, i.e. you're on the boost numerous times, seeing high 10s low 11s AFR every trip - city driving. The main goal is to find an oil that will maintain acceptable viscosity with 5% or more fuel dilution. I may have found it: Valvoline VR-1 60w...time will tell, I'll get it analyzed after 2000 miles. Also, a 1000 mile analysis is less useful, because most people don't change their oil that often. The goal here is not to just to generate a pretty looking report with low fuel dilution to post on the internet, anyone can do that by simply taking a road trip, the goal is to add value to the community - how most of us use our cars.

 

True but people have mixed driving styles.

You can have people who just cruise and do city driving.

You have people that do highway driving with the ocassional boost here and there.

Then you have people who just have a lead right foot.

I thought this was a post your report thread? lol

Not about what oil is best because thats just opinion. I mean pennzoil now goes in ferraris, does that mean we have to use it because ferrari does?

Either way, i threw in some M1 full synthetic 10w-30 so we'll see how that turns out after 1000 miles.

Gonna send the RP oil tomorrow. Cant wait to see the results.

 

Got my report today.

Nothing much has changed in 1000 miles from using good ol castrol gtx vs RP w/RP premix.

They advised that i should run my oil a bit longer. Did no more rice get banned again? lol



Running M1 right now, gonna take their advice and run it til 1500-2000 miles before i get that tested.

Then gonna just decide on a permanant oil.

 

The report is cut off, how many miles on the engine? Are you running 10w-40? The iron is not bad, even for 1000 miles, mine was 24 ppm with 4k miles

I would try a higher viscosity oil. I'm now convinced the rotary benefits greatly from high viscosity oil (i.e. at LEAST 20w-50, it not straight SAE 50 or 60, which is what I'm running now), because it runs so hot and turbocharging tends to shear the oil, in addition to fuel dilution (in my case and the case of most).

I severely doubt you can afford a C6Z, but a properly modded FD is hardly slow. What is your mod list?

 

Right now, 79918 to be exact. Ran 10w-30 the entire time of ownership and through these tests.



Now theres some informative output. Thats what i need, thats what people need from these threads. And yes i might do that.



LOL amazing assumption.

Is the general consensus of this forum is to assume any FD owner is broke? Im far from it mang.

Both of my cars are paid for and i have a mortgage. And i have a HUGE cd but im not the one to show off what i have saved so no point in bringing this further.

Btw, used C6Z's are in the mid 30s already. EASILY attainable. But i only have room for ONE car and the FD is here to stay til i die, i promised myself that.

And i cant get rid of DD because im not parking the vette on the street.

So theres your answer.

Mod list is all the bolt ons minus PFC. I would estimate 290rwhp?? Thats slow.

 

Got another report!!!

Ran this run a bit longer, a little over 1800 miles and wasnt happy with the results.

Either this oil cant put up with my driving style or just because this isnt good at all.

This is on M1 10W-30 full syn.




Im probably gonna just go back to either castrol gtx and change every 1k miles or maybe RP and change every 1.5k miles. Idk.

 

Another 2k OCI.

This time I went with Valvoline SAE 50 Racing Oil. My copper and lead wear dropped significantly, but fuel dilution was still high (5.5%). I took a 200 mile freeway road trip toward the end of the interval to try to burn off some of the fuel, but it didn't help much. Iron wear was also down, so that's good news. Notice that even with SAE 50, the oil still thins out to the equivalent of a 10W-30 after only 2k miles. Amazing.

Next OCI will be VR1 SAE 60 (yes, even in winter)

 

*crickets* anyone else tried a heavier straight weight?

 

Here is mine

Idemitsu 20/50 about 3-4,000 miles give or take. About 6-7k miles on the motor at the time of the oil change.

Hmmm....

 

Wear metals are quite high....3-4k is too long of an OCI for turbo rotary abuse imo - your viscosity is not bad, though

 

I agree on the oil change interval. I was using the car for lots of short trips and wasn't paying attention and the miles piled up. I typically change more frequently.

 

I was waiting for an idemitsu report.

I was going to run that oil to compare which i should use from now on.

Based on the 3 oils i have used, RP is probably the best for me, for my driving style. Its more expensive but its worth it.

 

Any unbiased test I've seen of synthetics consistently ranks RP at or near the bottom of the pack. Amsoil, Mobil 1, or even the newer synthetics from Castrol and Valvoline fare much better in both standardized tests and UOAs - look them up on BITOG...of course the way you drive, any oil will do ok I guess

 

Well based on the tests i've received, with the SAME driving style, RP showed the best results and M1 the worst.

Sorry i would take blackstones recommendation over yours. lol

 

Well, again, that's for your car and your granny driving style. I've seen many others tests and UOAs - RP is always shown to be inferior, but let's not derail this thread with a discussion about RP, start a new thread if you want