nycgps

iTrader: (4)

who said those Synthetics are expensive

I can get Mobil1 with any oil change special, 30 bux with Mobil1 filter (sometimes K&N), and every 5 points from Autozone gives me 20 bux credit to spend.

For Royal Purple and Redline, I can get them much lower than retail price (retails around 8-9 bux a quart for RP and 10+ bux for Redline, but I usually can get them around 20% off. not bad )

so its not that expensive really

I got them because they're "real" synthetics. not some bootleg fake wannabe crap like most of Castrol Syntec, Pennzoil, etc.

ZDDP kills CAT, it is somewhat proven BUT what they're doing is they lower engine's longevity for CAT's life. to me thats just stupid.

D Walker

iTrader: (1)

I am not 100% in agreement with the above, but again it is extremely difficult to actually prove anything about oil due to the myriad of variables involved.
Some things I have noted over the years-

Using Redline, Eneos, Torco, and the old formulation Mobil 1 oils we saw decreased wear, heat, and deposits in various engines, used both for street and race duty, over the oils used previously.
When I do use a conventional oil, I use Valvoline. Why? Because at one time they supported the SCCA Club Racing. I used Castrol because thats what the filler cap on my MG's valve cover said to use. A friend pointed out that Castrol was not paying me to be there but Valvoline was making it possible to be there. I switched to Valvoline. No other real reason. To this day I still use it, because no one pays me to use anything else.

I tend to not use Pennzoil, QS, etc because it is very hard to tell how much recycled oil they are using and there is no law making them disclose which of thier oils use recycled oil stocks and how much of a percentage is contained. Probably has no bearing whatsoever in reality, but once I dump oil out of my engine it needs to be used for something else, like making plastic lawn chairs.

All of this is opinion based on what I have seen over the past 20 years or so since I started paying attention to oil, which was probably about the time I started paying for my own engine failures.

arghx

iTrader: (3)

more internet forum hype

adding ZDDP to your oil might make you feel better, but it won't protect your engine from a catastrophic failure (overheat, detonation) which is what kills these engines anyway

I repeat: If you lose a non-original engine that was properly rebuilt, it will most likely be due to a catastrophic failure. The oil or additives you use will not save you from a leak, a tuning mistake, an overheat, or all the other things that directly destroy motors.

jackhild59

iTrader: (7)

If I was running a flat tappet Old School V8, I would really focus on maximizing the ZDDP up to about 1600 ppm.

I'm not.

j9fd3s

iTrader: (3)

the bearing wear could certainly be from the fuel not just the oil...

anyways, when dad and i cleaned up the Tr3 he looked into oils for it. he likes to make sure he's got the right oil, he runs german cars, and they demand it. rotaries seem like they are fine as long as there is something wet and slippery in there.

so anyways, after looking he likes castrol HD40. i have too. i've been running it in the Tr3, and its happy, and ive also put it in the P port.

on the P port mazda wants a straight 40 weight oil. there is some evidence to suggest that the polymers needed to make an oil a multi weight contribute to foaming, which the rotary is bad with.

not saying i found some magic elixir or anything, but it does seem to be a nice oil, and its not too hard to find either.

jjwalker

Dude, go put a bottle of straight 40 in the refrigerator for a few hours and then try and pour it. Holy **** it's like molasses.

In my old truck, I would run 10w-30, delete one quart of that and pour in a quart of straight 40. Once winter hit, I noticed this during an oil change and I stopped doing that (the bottle had been sitting in the garage overnight).

dimitry04

ok. well then in this case cuz i gotta fix an oil leak. involving removing stuff and all oil will leak out so i just gonna do oil change anyway. what should i run then. oil wise? i figured id ask here since there is an oil convo going

nycgps

iTrader: (4)

Ohio?

0w40 if you're lazy,

if you're not that laz use 20w50 for spring/summer/fall, use 0w40 for winter.

jjwalker

I run 20w-50 VR-1 like mentioned before. I live in Texas so it doesn't get cold enough for that to be an issue.

Don't know ohio's climate, but most racing oils are heavy weight.

dimitry04

ohio gets cold as hell in winter and hot and humid as hell in summer. lol. spring and fal are inbetween

D Walker

iTrader: (1)

Unfortunately, this is not correct. 20w oil at 80 degrees is still very thick and harder for the engine to pump.

In racing I use the lightest possible oil for the job, usually 0-30 or maybe 5-40, depending on what my expected oil temperature is. In AIR COOLED engines I will run a 0-50 Eneos or similar. If it is a true racing engine where the oil is heated before starting, maybe a 15-40 or 15/50.

Still, I prefer 0 or 5wt COLD oils. Knowing what we know NOW about dry starts and engine wear, it borders on irresponsible to use anything heavier in a street car, especially if you do the short trip thing where the oil never really gets warmed up.

dimitry04

ok walker you seem pretty good. what do you suggest for rapid change in temp?

j9fd3s

iTrader: (3)

good point, the two cars i mentioned arent DD's (they won't let me drive a P port on the street, and YOU drive a Tr3 when its 40F and rainy, i'm not!), the DD (stock FC) gets whatever is handy, 5-20 or 10-30 is fine, in the summer 20-50 is ok too.

the rotary seems fairly insensitive to oil weight, at least in a stockish street car. and hey mazda sells the rx8 with a 9000rpm redline and wants 5-20....

we're sort of lucky this way, some cars the oil you use really matters. i have heard of people missing an oil change on VWs and then the cam eats the lifters, @20k miles.

nycgps

iTrader: (4)

that is also why there were mad bearing failure in Renesis.

its a pretty common thing in the 8 community that 5w20 is such a failure and they recommend it only try to get as close to CAFE requirements as possible. of course there are always some ppl will say "oh Mazda knows more than you/in the manual they recommend 5w20" but the same people never listen to the part that saids "Mazda recommend to visit Authorized Mazda dealer"

My 8's original engine failed compression test @ 43K miles, in the 5 range. not sure what exactly happened, it was tested about 9 months before that and I got 7.x something that time. but worn out bearing might have something to do with it (increases Apex seal wear, poor injector location, too little OMP rate, etc)

The original engine sees 5w20 for around 5K miles, then it use 5w30 for quite some time before I switch to 10w40/20w50, but damages has been done and there is nothing I can do about it.

Rotary engine DOES care about oil weight, in the older days when almost everyone runs nothing but 20w50/10w40, not much issue. ever since 5w30 weight showed up engine life got shorter and shorter. and this applies to all engines. not just rotary.

not saying its 100% oil's fault but it does play an important role in engine life.

D Walker

iTrader: (1)

I have given my recommendations a couple of times above. I tend to use Redline for street and race cars, Eneos is good as well, and Torco is great when you can get it.
As far as weights, 0-30 cold weather, 0-45 or 50 when its hot.

nycgps

iTrader: (4)

Its kind of hard to get Torco and Eneos in NYC. have to be special ordered and price is not cheap for 0w50

Royal Purple / Redline much easier

D Walker

iTrader: (1)

I am going to dis-agree with this for the most part. The problem with Renesis engines and bearings is heat and contamination, not nec the weight of the oil.

I had at one point in time a very very good article on engine oil that I can no longer find. One of the key points was that you need to adjust the weight of the oil to maintain a specific oil pressure at a given RPM as recommended by the manufacturer. What this means is that if you are using say 0-45 oil and Mazda says you need to have 60psi of oil pressure @ 2000rpm hot, and you have 80psi @ 2000rpm hot, then you need to use a lighter oil, say 0-30 or 0-20. And by the same logic, if you are using 0-20 and you have 40psi when you should have 60psi, you need to use a heavier weight oil. NOTICE that you only adjust the HOT weight of the oil. 0 or 5 weight is still really too heavy for cold start even at 80deg ambient, but the aditive packages do not yet exist to make an oil act like a sewing machine oil cold and act like a 40 weight oil when its hot.

Mazda made some (bad) decisions regarding the RX-8 and some (really bad) assumptions regarding the service the car would see in the feild.

13B-RX3

iTrader: (2)

https://www.rx7club.com/showthread.p...highlight=zddp


Interesting read!

nycgps

iTrader: (4)

why I said weight because even with stock engine, with 5w20 there is no way you can reach the "recommended" pressure. you need at least 0/5/10w40 weight oil to get even close to it.

Lots of people ran test on it and had the same result. I even installed a Defi gauge just to monitor it.

Heat is another problem for engine with only 1 cooler(AT)

MT has 2 coolers and its keeping the temp in check (have oil temp gauge for that)

failures came from both AT and MT.

Mazda made a lot of bad decision on the Rx-8. they fixed all of them in the S2

rx7racerca

iTrader: (1)

This may not be the article you were thinking of, but it is a good source for choosing oil weights. It's track oriented, and assumes you have accurate oil pressure and oil temp gauges, but still holds regardless of the application.
http://grassrootsmotorsports.com/art...lippery-slope/

The gist of it: use heavier weight oils only if oil temps rise outside of the acceptable range, or pressure is inadequate. Most of the time, factory recommended oil weights work at the track as well, and many run too high weights.

Nice to see a useful oil thread.

K-Tune

iTrader: (26)

You're absolutely correct. Our engines don't have anything that simulates "flat tappet" friction, all of the friction surfaces in our engine are oil cushions. The need for high zinc and phosphorous in rotary oils is quite low.


Rotary engine oils biggest problem is fuel dilution, which is why many of us run "thicker" weights so as to offset the thinning effect of the fuel dilution.

jackhild59

iTrader: (7)

I haven't heard anyone mention the fuel dilution issue lately, maybe because much of the 'Old Guard' left the forum.

There are many old threads that speak to the issue of rising oil levels due to fuel accumulation/oil dilution.

This can become an issue when the OMP is removed for premixing. Oil is not used and replaced as on a stock system. It can be further magnified when the AFR is 'tuned rich' to prevent detonation. Unburned fuel accumulates in the oil. Now apply the situation to a turbo car that is making lots of extra Hp, is driven hard but is not driven long enough at a time to have the extra fuel driven out of the oil by heat and run time.


That would account for some of the bearing issues, would it not?

nycgps

iTrader: (4)

there is a huge thread about the fuel dilution on the 8 forum, with oil reports and details.

Same conclusion, use 5w20 means you hate rotary engine.

K-Tune

iTrader: (26)

The severity depends on things like side seal clearance and tune, I don't believe with 3,000 mile oil changes that the dilution causes that much of an increase in the acceleration of bearing wear. With extended oil changes however...

D Walker

iTrader: (1)

Yeah, fuel dilution is a seriously individual issue. Personally, my cars never see serious fuel dilution because the oil gets changed. On the e85 car this was a concern, but with good premixing (and soon the OMP with external feed) no issues with dilution or other contamination.

As an aside, modern oils, regardless of zddp content should handle a fair amount of fuel dilution before it becomes a concern. In a 4G63 turbo motor we once saw a fuel issue that resulted in oil that literally smelled of gasoline, and had been run that way for at least 2k miles. A later tear down due to HG failure showed virtually no bearing damage or damage to the cylinder bore/piston skirt.

As always YMMV