olddragger

iTrader: (3)

here is some interesting info.
i ran royal purple for 2 yrs --10w30--when i tore my engine down the front bearing was down to the copper.
here are some oua's
1706 image is from havoline 10w/30
1707 is havoline 10/40
1708 is from castrol 10/40
1709 is from Shell deisel oil 15w/40!

http://garx8club.com/v3/download/file.php?id=1706
http://garx8club.com/v3/download/file.php?id=1707
http://garx8club.com/v3/download/file.php?id=1708
http://garx8club.com/v3/download/file.php?id=1715

take note of the viscosity readings at the bottom.
kenny fc is a good guy that has been and continues to work on oil issues and solutions. He presently is working on a safe zinc/phos additive.
I am sold on diesel oil
but to everyone else--take it for want it is worth to ya.l
olddragger

rotaryPilot

xa xa xa yes you are so right All that chapters that I did read ALL OF THEM and the end just "follow manufacture's choice"

cidvicious831

so what do you recommend? and what wight?

Flashwing

Well let's find out!

I'll use redline oils as an example because their information is easy to find.

Redline 5w-20
cSt @ 40 degrees: 55
cSt @ 100 degrees: 9.1

Redline 20w-50
cSt @ 40 degrees: 148
cSt @ 100 degrees: 19.8

That's a cSt difference of 93 and that's at 40 degrees! That isn't even accounting for the viscosity of the oil when the climate is colder.

Now, compare that to the cSt of the oil when it's 100 degrees celcius and your looking at a 10 cSt difference. Since the normal operating temperature of an RX8's oil system is 180 degrees farenheit then that puts it 32 degrees lower than the tested temperature of motor oil so the viscosity difference between the two oils will be a bit larger.

A 20w-50 oil may protect better at temperature however with the vast majority of drivers not waiting for their oil to warm up before going heavy on the throttle it's a sure bet you're doing way more damage when it's colder.

So, let's assume for a moment that 20w-50 is the perfect oil for the rotary engine. This would mean the 19.8 cSt is the optimal protection for the bearings. That means that you have a difference of 128.2 cSt between startup and operating temperature. Clearly viscosity changes as temperature increases but that is a hell of a difference. Couple that with people driving the car in ranges where there isn't enough lubrication during those times and you have a serious wear problem over tens of thousands of miles.

Comparing a person's reaction to a chemical and how engine oil reacts in a motor are two completly different situations and cannot be compared on any level what so ever.

The whole process by which oils are tested is based around "real world" situations in order to simulate the conditions of wear and tear on a motor. Oil manufacturers also work close with the car manufacturers since neither industry can manufacture their product without knowing what the other industry is doing.

The marketing system by which oils are sold is already flawed. As an example, gear oils are believed to be thicker than engine oil (compare a 75w-90 gear oil to any engine oil) but the truth is a 75w-90 gear oil has the viscosity of a 10w-30 engine oil!

Plus you have oils being marketed as "synthetic" when they clearly are just tweaked base Group III oils. Group IV and Group V oils are the only true synthetic oils but the marketing doesn't work out that way.

A 0w-20 is marketed as a "fuel economy" oil but a 0w-20, 5w-20 and straight 20 all have the same viscosity @ 212 degrees! How is one a fuel saver and the other isn't??

I wouldn't trust any of the marketing or hype what so ever.

9krpmrx8

iTrader: (46)

Good explanation Flashwing. Very well put.

ayrton012

The oil pump's part numbers:
RX-7 FC 1985- NA: N326-14-100
RX-7 FC 1985- Turbo:N318-14-100A
RX-7 FC 1989-NA: N318-14-100A
RX-8 2003- : N3H1-14-100

The numbers are not the same, but you will see later, that inside the pump's house, almost are all the same. Interesting that they used the turboed 13B's stronger oil pump in the NA from 1989.

The part numbers of the oil pump's rotors:
RX-7 FC 1985- NA: N326-14-140
RX-7 FC 1985- Turbo:N318-14-140
RX-7 FC 1989- NA: N318-14-140
RX-8 2003-: N326-14-140

Strange, that they pulled out from the drawer the old NA FC rotors for the Renesis oil pump.

The oil pressure regulator valve is the same in all of the modell above.

They raised the performance with almost 50%, but they did not modified the max. oil pressure. So they did not worry about the cooling affect of the oil flow.
Maybe the Renesis II. is the first rotary engine where Mazda recognize the unique oil pressure claim of the rotary (mainly Renesis). Could it be possible?

nycgps

iTrader: (1)

I think people are too into "cold start up protection" way too much.

The fact here remains is that : people use nothing but 5w20 oil are seeing engine failures.(North America market) Also this is NOT just rotary alone, its happening everywhere(yeah, piston engines too). And we're still the only place that recommends 5w20/0w20 kind of BS.

on the other hand, people who use nothing but 20w50 (or 10w40) kind of engine oil are all ok except normal wear and tear. Dont look too far, just look at the FC group, 20w50, some even use straight weight 40 or 50 oil. no problems for 200K+ miles. If cold-start up protection is really all that important, their engines should have "much shorter" life than people that use 0/5w based oil. right? but the fact is that, its actually the opposite.


Its engine damn it ! Not motor ! :P

of course its different , just trying to explain my point of view thats all.

of course. they cant live without each other



I know that part, but I dunno why they have to call it 75w90/80w90/75w80/whatever for gear oil, maybe people are too dumb if they dont double or triple the number, some morons might just grab an engine oil and use it in their gear box cuz they think "Its just the same thing, why pay more for gear oil when I can get that Autozone 10w30 conventional for 2 bux?"

Thanks to the US law system, we're the only place that we can have Group III as "synthetic" oil

In fact, they all are marketed as Fuel saver.

Who does? but sometimes what they're telling its the truth (although kinda rare that an AD is telling the truth)

Again, if Brand X is saying their brand's product is better than Brand A, then we should be more careful.

nycgps

iTrader: (1)

Yep, I noticed that for a while too (not that long ago actually ... just after I got my FC)

Mazda failed again ?

9krpmrx8

iTrader: (46)

I ran nothing but 10W30 and changed my oil every 3k (had to provide documentation to prove it) and it didn't help a bit. So now people are gonna say, "oh, but 10W30 is not enough, you need 10W40 or 15W40". But everyone was screaming 10W30 was the best.

I have read a lot recently and it seems to be a fact (supported by both sides of the aisle) that most engine wear occurs at start-up.

And, as OD and some other rotary guys have pointed out, Synthetic is better but not a cure all as guys that have run pure synthetics and seen bearing wear. Some people seem so set in their convictions about oil when in reality very few have data to support it.

ayrton012

Maybe. If I take that they recommend the xxw-20 weight oil, that can't bring the 51 PSI/3000rpm/212F data, which is their reference, what can I say? Mazda failed.
They offer you something, which is not offerable according to their technical sheet. ?! To be sure in it, we need more data from xxw-20 users, whose have pressure and temp gauges.

Otherwise I'm a fan of Dr Haas's article. He say's, use the thinnest oil which meats the factory reference in every situation of your driving (your driving conditions!!!).
I use Mobil-1 0w-30 from the beginning.

olddragger

iTrader: (3)

the cst's quoted are good info.
Recommended cst at normal operating temp is approx 10.1
This temps are in C arent they?
5w/20 doesnt cut it. most people are not running 180F oil temps--unless they have done some major mods.
that cst may be listed but how long does it hold it? a 50w will be down to the cst of a freash 30w after just a little.
Did anyone look at the oil analysis studies i posted?
Cars spend much more time in the hot range than in the cold range--load it higher, rpms are higher etc.

9krpmrx8

iTrader: (46)

couldn't see it without a login OD.

nycgps

iTrader: (1)

In the old days, Mazda tells you how to check for engine internal problems, like specs/clearance in the FSM. But u cant find them anymore, too little people know Rotary engines in North America (they stopped making them for almost 10 years for the US market) and it takes too much time and money to train everybody. So I guess thats the reason why they dont allow any of the US dealerships to open the engines up (not sure about any other place but in Japan, they do allow techs in dealerships to open them up)

There is almost no way to know what exactly went wrong inside your engine. Dont forget some of the early rebuilds are pretty crappy. So you might got a bad rebuild in the first place.

Mazda did not provide a chart for "different climates" like older days, they just "recommend" something and "hope" that it works for everybody. Sometimes "hope" doesnt mean it will work. and the result is a lot of people who lives in the hot climate like you, end up with a dead engine.



This kind of chart appears in almost all older car's user manual.

I remember my father's 1995 Nissan Quest GXE user manual has some chart like that too.

but nowdays?? nope. you wont see something like that.

For example, I just scanned my Honda Fit's user manual page about motor oil in :



To me, this simply means that, auto manufactures thinks most user are not smart enough to figure what oil they need for their engines, So? Just "recommend" something and most people would follow, yay ?

If we look at the chart #1 again, temperature anticipate before the next oil change : 5w-30 is good for 0 to >-30c. 10w30 is good for -25 to 30C . the widest is probably 10w40/10w50, -25C to >50c (we be dead if outside temp is over 45celsius. just saying)

Oil technology has changed since 20+ yrs ago, but there are certain things wont change no matter what.

People said most engine wear happens at start up, that is true, but Im sure Mazda or every other companies know that way before even 1/2 of us are here even born. they still put the chart up. and if 20w50 engine oil is so bad for engine start up, they should've change it to something else.

But the result is actually opposite, people use 10w40 in the old days and they dont have a problem. Now? wow, engines are breaking down left & right everyday, every since The wonderful "thinner and supposed to be "better" oil introduced" sheesh.

One more thing, Anybody noticed that they're "recommending" the same oil for My Honda FIT? 5w20 dude. and my FIT's redline is what? 6K ? I dont even rev it that high cuz I get no power after 4.5K anyway.

what our e-shaft will see ? more than 6K right?

and everybody still trying to tell me that 5w20 or 5w30 is "good enough"

Even my Honda FIT dont use 5w20, I put 5w30 into it, cuz I got a good deal on Mobil1 with Mobil1 filters (hey, only cost me like 20 bux for a case of 6 quarts + mobil1 filter, I dont see why not!), when its done (maybe a year or something) Im going to use 10w40 or something for the FIT.

I dont know man. I think Im almost done with this thread.


I can do that, let me just go out this or next week and grab a whole bunch of 5w20, flush it 2-3 times, then test the pressure.

kennyfrc1

iTrader: (6)

Used oil analysis tells the story and the rest is speculation.

Anything that says SM or GF-4 on it should be avoided.

nycgps

iTrader: (1)

Its just sad that most engine oils are getting "SM" certification even tho its actually "garbage" when you compare it to the older SL spec.

in fact, most thinner weight oil got that certification already(sad), its just the heavier oil like 20w50 we can still see SL even SJ spec on it.

Why? cuz most people think latest/newest is always the greatest.

nycgps

iTrader: (1)

Yep.

I dont know why everybody said Renesis's usual engine oil temp is 180f ---- I barely see that, at least not after 15 minutes of stuck in traffic conditions.

Even at cruise , about 85f outside, I will see at least 85-90 Celsius --- which means 185-194f.

nycgps

iTrader: (1)

One more thing --

I dont know why newer Rotary people are so afraid of using heavier oil weight, and will try to find tons of so called "information" so they will say "we got this to back us up"

if I never got my FC I might agreed with you guys, but after I got my FC, not sure if anybody noticed me but, I was "pretty much disappeared" from the rx8club, while Im doing my "studies" over at other 7 forums (like fc3s, Rx7club, etc etc) and I was actually pretty surprised that most people will say you are nutz if u tell them you use 5w30 for your rotary (5w20 they will tell you to fuxk off)

Forget about Rotary for now, Look at what BMW recommends for their M series, BMW actually recommend 50 even 60 weight for their M series. Dont tell me M series got no high performance engines.

Spin9k

I don't either buy this fascination and belief in the urban legend of "the most engine wear occurs at startup and so I MUST use some such low viscosity oil before I think about any other oil performance critera. It's shear and utter bullcrap to think that way in all but the most extreme cases (Canada, the artic, antartic, and other cold places )!

Do we start and stop our engines after 5 or 10 minutes wait for the cooldown and then repeat over and over? of course not. Startup/warmup is such a miniscule percentage of the total engine run time as to be insignificant to overall wear. People start their car, and unless you're a douchbag you probably don't immediately do successive 7000rpm launches in the 1st couple seconds or even minutes...I would think anyway. You drive and go reasonable, or even long distance or long timeframes compared to the seconds of startup.

How can it be proven beyond a reasonable doubt that during the short period that the higher viscosity of ANY oil quickly wears any part in an engine? I've never seen that study, report or anything else. It's a myth until someone can show me proof.

What does destroy engines is using the incorrect lub for the work the car will be asked to perform or not changing the oil when it needs changing and therefore the accumulated dirt particles/debilitated oil performance causes wear. Everyday use like that kills things in an engine. Carbon builds up over long periods of time, seals wear or break over time or due to abuse. Housings...well there's one remote possibility for startup wear, but again I'd say remote. Housings aren't made of pot metal - it'll take a long time to wear unless subject to abuse. There are cases of bearing wear, but this is not the primary failure mode, and again who can prove that wear occured during startup?

Bottom line, we should focus on the primary normal uses oil needs to perform, and when it is at it's normal working temperature or above for heavy duty use. Pegging a choice on startup is so shortsighted in most cases, you'd be better off choosing on whether you like the color of the oil or not.

Charles R. Hill

iTrader: (7)

The flip side of this coin is that some may think the perceived "mad dash" to use higher viscosity oil is equally reactionary.

The fundamental aspect to the dicussion, as it now stand and as I see it, is how much priority one wishes to place on the cold-start concern versus the operating temperature concern.

BTW, I have used 20W50, 15W40 (long before it bacame a discussion around here), 10W40, 10W30, 5W30, 0W30, synthetic, "dino", blends, etc.

Perhaps I will next try some 0W40 and 0W50 just for fun.

Charles R. Hill

iTrader: (7)

I remember learning this in school but that was 25 years ago so I may not be able to quickly access the SAE study that such a premise was based. I am sure someone around here can link us to it, though.

Charles R. Hill

iTrader: (7)

There is a reason the OEMs take this approach. I can explain it, if you like. I may have already done so in this thread, anyway.

nycgps

iTrader: (1)

I know you've try almost everything, damn you bastard if u have so much free time, stop playing with oil and go make some cool stuff for BHR !!!!!!

Well I mean, all engine oil will work, but is it ideal ? everybody has a different answer.

and my own answer is --- 20w50 works, and probably the best for this type of high rpm engines. your opinion, flash, or my neighbor's opinion will be different. so ... i dunno man, Im really really almost done with this thread.

Spin9k

If it was done over 25 yrs ago I would say it is no longer valid given improvements in oil formulations, not to mention synthetic oil, and improvements in the hardness and wear ability of metal surfaces; bearing, coating, and such.

How about something done at least this century old guy or I won't budge my 'urban legend' claim!

Charles R. Hill

iTrader: (7)

Since this thread has run it's course (for the most part, anyway) please allow me a slight "threadjack";

1) Free time? Hardly. The best example my own car serves is to demonstrate the carelessness one can exercise with the Renesis/RX-8 and have it still run like a top. All I do is keep the air filter clean and check the OMP and oil pan oils often. Ask the BHR crew and they will tell you.... I have no time to even work on my own car and I do not even WASH it as often as the rest around here. I had to set aside time the other day just to check and confirm that my swaybar end-links are bad. They are and have been for over a year!

2) I am not promoting any particular viscosity or brand of oil. All I am trying to do is educate others on how the OEMs develop the processes they have and why they take certain approaches on things so they can make the best-informed decidions for themselves.

3) We don't need to be done with this thread if we allow ourselves to delve into other related issues. Otherwise, you are correct.

Spin9k

Hey, I'd like to see that one... "yellow is better...thin like ****, orange is not so good .. to many additives...brown is well, like ****, no good - get it outa there!" is that the rationale of which you speak?