I agree with you in priciple on this, but what you are describing is just anecdotal. Please shrink those pics. I hate to read stuff by sliding the page backand forth

 

Pretty simple fact is that most FC owners, at least NA owners, use nothing but 10w40 or 20w50. their engines can go WAYYYYYyyyyy longer than our little "5w20 wonder!" without problems.

That should tell everybody something, right ?

I deleted the link, just click the pic to see it.

 

Most RX-8 owners never had a rotary before.

So yeah they had no experience. including me

With the exception of 13B-REW, all older rotaries can go longer than ours without much problem. and they all use heavier weight oil(5w20 doesnt even exist back then!) plus they dont have this pathetic "recommend XwXX weight oil ..." thing.

Sure, its been 10-20 years since then, oil technology has improved, but there are things in science that no matter what you do, it will never change.

no one else got this "engine recall" bs. and we're the only one recommends 5w20. hmm. didnt we talk about this before in other threads ?

and now I got my FC (about a month something 2 ago), the car has been beaten to death and its not very safe to drive (my opinion) , so I start doing research on it on what are the common problems it has.

guess what, ENGINE IS NOT one of them. I actually learned quite a lot from working on my FC, now I know how to do all shocks, rebuild calipers, pads, rotors, hubs, DTSS(its a FC thing, what a bitch to remove/replace), throttle, etc etc ...

and of course, the more I research, the more I hate the Mazda's 5w20 bullshit.

oh yea one more thing, im not sure about FD, but in FC's FSM(S4 and S5), they actually teach you HOW TO disassemble/check/reassemble a ROTARY engine. step by step, hmm, not bad. I will try this myself one day

its gone.

 

Again, I would agree that it is likely that these oils provide superior protection, but without published, rotary-specific studies, it is just speculation. Either way.

As for the loss of compression that we are seeing, is this oil or poor clearancing of seals?

I do not use 5w20. I rarely have and only in the winter back when I was NA.


Thanks, man. Much easier to read.

 

Not always that simple. I wonder how many changed oil when they should have and how many failures can positively be identified to the motor oil selection's fault? And how many switch from the 5w-20 mineral based to a syn heavy weight 40 or 50? That's not a valid comparison, the biggest contribute would be the change to syn, not the weight change. And most people I've read here who had engine failure were far before the 80k mark. I seriously doubt those had anything to do with oil selection.

If someone changes their oil at the 3k mark all the while, regardless of what oil used for a typical driver not abusing or racing it should hold up past 80k. Only then those who have failures after that mark IMO have relevant analysis to use based on consistently used oil weight. Those who blew engines at the 20, 30, 40, 50k mark all agreed that Mazda recognized the engine flaw which means it didn't matter what oil you chose, one way or another you were F'd.

I think you're getting the notion that thicker than what Mazda "recommends" is bad, that is not my opinion. Based on the article and people's issues here, I think 20 perhaps is too thin in the long run, but anything over 40 is too thick. It involves a fine line. Sure 40 and 50 even 60 could work. Doesn't mean you're optimizing the engine by using them just because they work better than a 20.

A 0w-30, 5w30 could possibly be even better than any 20 or 50 weight especially with better cooling due to better oil flow in the engine. The 40 would be as high as I'd go for latter end oil weight selection. Anything higher I believe is overkill. To benefit the Rx8 community the most, someone would need to experiment with different oils each change and record coolant temperatures, oil pressure and MPG to discern what oil works the best.

Now what I would like to know is who has expertise on using syn based oils on '06 and higher engines with no Apex seal issue?

 

I'm a 5w-30 person. This is a good read. I went from starting this article to thinking 5W-30 is fine. I'm good, then by middle I"m thinking perhaps going 5W-40, and now back to thinking I'm fine with 5W-30. Shoot I dont know.

 

IMO, its better to use heavier oil, syn or not, than lighter oil.

one thing a lot of people seems to forget is, fuel dilution. It affects the viscosity a lot.

If you know the engine's spec (like all the clearance), you will know its actually not that diff.(some areas are tighter, but should be ok for heavier oil to sweep around). Its still 13B

I have temp gauge installed, I can tell you its about the same.

Will have to see.

 

To be honest, my opinion is the oil selection will have to do with the engine long down the road over 80k miles. Anything that occurs before that likely will be a fluke failure not contributed to the oil. If you change the oil every 3k, then I have no reason to suspect the oil selection was the issue in the first place. Yes it's a Rotary, yes it's a finicky oil using design, no it's not partial to die in 4-5 years with fresh oil placed in it ever 3k miles regardless of what you chose. For a typical driven car, it's fresh oil regardless. If you abuse the car and race it, redlining it all the while then that's another story.

If anyone has a high mileage 7 or 8 with no engine trouble, list what oil weights you used and why. I wouldn't be surprised if the numbers varied all over the place.

 

I have no doubt that Mazda picked the 5w-20 with emissions and fuel mileage in mind.

The primary problem with your argument is that "film strength" has more to do with the makeup of the oil and it's additive package than it does the oil's weight. Since bearings are hydrodynamicly lubricated the oil is going to occupy the same space regardless of it's weight. If you assume that flow = lubrication then any oil which flows less due to increased viscosity lubricates less.

If hydrodynamic lubrication breaks down and the oil is sheared then you're looking at barrier additives to help prevent damage to the metal. That kind of stuff is going to vary somewhat I imagine between brand and oil type.

I honestly wouldn't pay attention to the marketing that is put out by these companies. The whole aspect of marketing has been to fool people in the first place. Most oil companies market Group III base oils as full synthetics of which they are not.

For Castrol 5w-50 all I could find is the viscosity @ 100 degrees C so 212 degrees Fahrenheit.

Viscosity @ 100 âC, cSt.: 20 typ.

For 5w-20 viscosity @ 100 degrees Celsius was 9 cSt.

Again, what is unknown is the optimal amount of flow needed in the RENESIS. However, assuming Haas's numbers are correct you're looking around the 10 cSt region within the operational conditions of the motor.

One part I missed that was buried at the bottom is the notion that approx 20 degrees of temperature separates the various grades. He states that if you are running your oil at 220 degrees and it's a 30 weight, it will provide the same cSt as a 20 weight at approx 190 to 200 degrees.

So it seems that if you're simply daily driving the car then you could get away with a 20 weight oil and be fine. If you're on the track you could use a 30 weight and maintain the same flow at a higher temperature.

Yes, if you notice Ferrari specifies that the 10w-60 weight is for high temperature racing conditions. Haas explains this as well.

The RX8 manual lists various oils and their operational temperatures. Nowhere does the manual say you can/should use these oils nor must you use exactly the same oil Mazda suggests.

In the end it's your car and up to you. My point is we've been pointing fingers at the 20 weight oil saying it's bad and how it's responsible for engine failures. I think the true culprit is insufficient OMP injection.

 

Amen, brother. I read every word of that article as well as some of his other stuff and so did my dad (who is much smarter than me in terms of engineering) and personally we have come to the following conclusions for me.

1. I will use 0W-20 Mobile one because I now believe our damage is being done at start-up and because of poor OMP design/volume as for me, running a thicker oil did not help.

2. I will premix with a synthetic 2 stroke.

3. Instead of just letting my car get up to normal water temp, I will now wait for the oil temp to be up before I take off on the highway. And I will not use my RX-8 for short trips.

4. Though I will be using synthetic now I will still change my oil every 3k.

5. I will also be getting the AP and the Mazmart water pump and thermostat.

5. I will also change my tranny fluid every 3 oil changes.

 

[QUOTE=9krpmrx8;31276041. I will use 0W-20 Mobile one because I now believe our damage is being done at start-up and for me running a thicker oil did not help.

2. I will premix with a synthetic 2 stroke.

3. Instead of just letting my car get up to normal water temp, I will now wait for the oil temp to be up before I take off on the highway. And I will not use my RX-8 for short trips.

4. Though I will be using synthetic now I will still change my oil every 3k.

5. I will also be getting the AP and the Mazmart water pump and thermostat.

6. I will also change my tranny fluid every 3 oil changes.[/QUOTE]

1. What "damage"?
2. Make sure it is pre-mix compatible.
3. A minute or two, especially in TX, is fine. Just don't go WOT for a bit.
4. Synthetics can go much longer between changes. I change my own based on the appearance of the oil and not based on mileage.
5. Good choices for cooling control.
6. Every 9,000 miles?

If you guys saw what I have subjected my own engine to.... you would wonder how in the Hell it still runs.

 

Please understand in what context I am speaking when I talk about engine wear at startup. None of this stuff happens overnight. You could easily go 80,000 miles on a motor in which you have wear happening upon starting the motor.

Regardless of whatever oil you use the simple practice of giving the motor a minute or two to idle before taking off will help. As Ray pointed out as well, don't go bouncing off redline right away. You should have enough oil flow at lower RPM's to handle the engine demands. It's when you're nailing 9,000 RPM's with your oil not even past 120 degrees that you have issues.

A good manual transmission fluid doesn't need to be changed every 9,000 miles. It doesn't have to deal with contamination like engine oil does.

I'm not claiming to be an expert so you can take my opinion/advice in that regard. I'd like to be an expert at one point. I simply follow the logic of much of the material I've come across and I see logic in Mazda suggesting a 20 or 30 weight oil for the RX8.

 

But also complicated by some realities which argue for heavier than 5w20

- excessive bearing wear noted on teardowns

- engine oil temps which can soar in very hot/dry climates at low speeds as the RX-8 cooling system is marginal in those conditions.

- Fuel dilution (though much less of an issue than with early flash revisions)


Empirically, we have seen high engine failure rates in areas with hot climates and 5w20 recommendation.

Theoretically, I'd say part of the issue relates to the half-life of OMP-injected oil once it's on the housing.

I used synthetic 5W30 for a few years. Now I'm hedging my bets with synthetic 0w40.

 

yes my second engine running 10W30 last 50k more than my first. By damage I mean wear that occurs at start-up. And for transmission fluid I feel the more changes the better. I have been changing my transmission oil about twice a year and it has lasted 95k without issue and so i figure more changes may be in order. I would like to get 100k out of this motor.

 

Not really - a lighter weight, synthetic oil will transfer heat faster than a heavier weight oil due to the extra flow, and peak oil temperatures shouldn't be a problem for a decent oil at low speeds, even if the water is struggling to cope.

Added to that, hydrodynamic bearings rely on flow to work, more flow, provided you can maintain enough pressure for the bearing rpms, will preseve the bearing, not cause it to wear.

 

ok, how did 5W20 kill your engine? The fact is neither you nor Kevin actually opened up your engine to see what was wrong (as per Mazda's orders)...

https://www.rx8club.com/showpost.php...2&postcount=72


and again your trading a 10x wear penalty for a 20W50 oil for every frikkin cold start of your engine in hopes of a slight lessening of wear in extreme high temp racing applications?? Is your car a daily driver, or a 100% track machine?

 

On the idea that bearings are being damaged; I have yet to need to replace them in any of the rebuilds I have done (and my own bearings over two years ago were the WORST I have ever seen in a Renesis). Conversely, a couple customers who used Royal Purple 5W30 (without a Sohn OMP Adapter) from "Day One" had me rebuild their engines and their bearings were not even scuffed past the top aluminum layer. I also have another engine I am building that has bearings which look like brand-new.

 

Charles, in light of a question I was inquiring if anyone knew about in regards to the syn oil with apex seal combination; do we still know if present day engines have issues using syn oil in regards to what I believe people referred to as deteriorating the seals due to the synthetic or rather reducing its life expectancy? Any comments or thoughts on this based on the rebuilds and with what mileage?

 

BINGO, Justin.

Within your observation lies what I do for a living for BHR; break the "bad" news to people that their particular driving context is nowhere near the Speed Racer situation they think they have which requires exotic fluids/oils, heavy clamping force clutches, super-stiff suspension springs or coil-overs, high-temp brake pads/BBKs, and on and on with all that marketing mystery which pervades this industry.

For years, we all in the RX-8 community have convinced ourselves that just because we hit the occasional autox or HPDE event that we need "racing" products when, in fact, that time on the track constitutes less than 1% of the actual driving time of the car.

There is a strange, and comedic, irony in all this too..........

 

This is pretty much what I've been trying to explain the entire time ....... but perhaps a more brief approach would of gotten the point across as you showed.

Charles, I think your response right after mine was quick to where you missed a question I had intended for you to share your experience on.

 

I assume you are asking which type of oil is better for apexes; dino or synthetic. To be honest, I haven't enough empirical data/info to come to a proper conclusion on THAT particular question. What I can say is that I have the Sohn OMP Adapter and I use synthetic oils in both my crankcase AND my OMP tank. I have used all sorts of 2-stroke oils, both high-quality and low-quality (as has MazdaManiac), and I have even accidentally run my OMP tank dry a couple times (for a couple hundred miles each time. Stupid me.) and my engine still runs pretty decent and makes 213 at the wheels. I should probably check the compression one of these days.

On the other hand, those rebuild customers of mine who used RP 5W30 did so with no OMP adapter. This means they were also using the RP as OMP injection oil as well as crankcase oil and their apexes were bad but all other parts were fine. Better than fine, actually.

This is somewhat my point; I believe the low OMP volumes are more an issue than whether or not we should be using syn vs. dino, a particular viscosity, and what have you. Should we be thoughtful about it? Sure. Obsessive? No.

What is the best "solution"? Again, merely my own opinion, a Sohn OMP Adapter filled with whatever 2-stroke oil you prefer (I have used AMSoil, Pennzoil, Walmart, and now RP) and whatever synthetic oil you like in the crankcase. A Cobb AP with the OMP volumes doubled (or maybe tripled like mine) across the RPM range, will help too.

In my oilpan I have used 0W30, 5W30, 10W30, and 20W50. Cold starts were the primary thing that revealed differences with some perceived throttle response differences, second.

 

Throw the OMP in the bin and do a 100:1 premix. Sorted :D

Be interesting to see how our engine is holding up vs what it was like when we got it, probably strip it down this winter for a look.

 

Pre-mix has it's own encumberances and the context you are exposing YOUR car to, Phillip, is far different than 99% of those reading this thread.

 

Well, for the sake of carrying a little bottle of -stroke around and adding a bit every time you through a tankful ( every what, 300-400 miles?), isn't that bad surely?

For the average buyer perhaps, but I'd imagine everyone on here is more of an enthusiast.


Flat-out, everywhere!

 

With over 500 customers, and more new ones every day, I can tell you with at least a little authority that the RX-8 market is a different than you might think.