ROSHX7

So many people using so many different weights..its so confusing. Ok, can some EXPERT hear set the record straight...if you really really care about your ROTARY engine and want it to have only the BEST stuff...I guess a great quality oil like MOBIL1 is a good place to start..but how about which WEIGHT to get?? What you guys ULTIMATELY recommend!??

thomasmeisch

Any high quality 10W-30 will work fine, the most important thing is to pick your brand and stay with it. The different additives they put in there products dont agree with each other and cause gumming and buildup. I run Castrol GTX 10w-30. My mech. recommends it and he should know hes been working with rotory's for 27 years!

tesla042

I use gtx 10-30 also... maybe 20-50 in the summer, but there's nothing wrong with 10-30 all the time..

just, DO NOT use synthetic..

-Tesla

ROSHX7

Thanks guys, I'm going to stick to 10w30 then. Since its cold out here in Canada most of the time. I tried using PENNZOIL SYNTHETIC with Pennzane last oil change...i was worried about it. It burned a lot faster, like It would use up more oil then normal. I had to keep adding in a liter 2 weeks. So now I switched to regular PENNZOIL, and it doesn't burn as much....like needs a liter every month instead. DON'T know what's up with that?! Oh the PENNZOIL Synthetic was 5w30 and the regular one I'm on now is 10w30...don't know if that matters much.

blue88gxl N/A

nice car roshx7
Do you got any pics?



fellow rex owner

go_speed_go

Yeah, because the guys at Racing Beat and Rotary Performance don't know what they're doing ...

tesla042

Also..I heard that pennzoil has some certain property that makes it absorb water..or not absorb water..or something.....that makes it bad.. or, at least, worse that other oils.. heh..

-Tesla

tesla042

the original "don't use synthetic" argument came about back when synthetics weren't as advanced as they are now. They didn't burn as cleanly as regular oil, so they left a larger amount of deposits in the rotor housing, and on the rotor. The general concensus of the forum seems to be that the newer synthetics probably won't hurt, but why risk it?

Are you referring to a specific car from RB and/or RP? Maybe they blocked off the oil injection and ran premix.. in that case, it's perfectly fine to run synthetic, with no risk.. Or, maybe if it's a race car, they expect to tear it down often enough that the little deposits synthetics MAY leave are going to be cleaned out...

I hear synthetic oil does wonders for turbochargers... if i had one, i'd probably block off the oil injection and run it...

-Tesla

ROSHX7

Yeah for sure man, here is 3 I just took a week ago.
http://www.rosh-site.cityslide.com/a.../102468/959073

http://www.rosh-site.cityslide.com/a.../102468/959072

http://www.rosh-site.cityslide.com/a.../102468/959074

ROSHX7

OH CRAP!!! I only used it cause a bunch of mechanics swore that Pennzoil Oil is the BEST, but I guess its because it causes more engine failures so they get more BUSINESS!....****!

go_speed_go

Racing Beat recommends Royal Purple for Rotaries. I ran synthetic on my '84 and my '90 without a problem. The '90 had been overheated once by the DPO, so the motor only lasted to 130K. When it was torn down, I had been using synthetic (Amsoil 5W30 & 0W30) for the last 40K miles. The inside of the engine was immaculate. No sludge, no deposits, no carbon, just a hairline fracture in one of the coolant passages.

Synthetics were not recommended in the early days bacause one (and only one) brand (in the 70's) had problems with burning off. Mazda did't want to single them out, so they decided to only recommend conventional oil. This isn't folklore, it was in a magazine article back in ~'95 which was an interview with a Mazda exec discussing the rotary engine and the demise of the FD.


Oil type for rotaries is a very personal decision and either side can be justified/correct. I just can't stand reading "Never use.....".

thomasmeisch

Nothing wrong with penz. Its additives are pat. so not used in any other oil. This is why it is NOT good to mix oil brands. The additives cause the problem when mixed not the oil. I did a paper on oil a year ago learned alot. Never thought it would be useful to anyone but me though. 230,000 mile on my Blazer, 5w-30 Penzoil ran in it since I picked it up with 230 mile

Long, detailed, more then you want to know about oil deacription........

The proper viscosity is the single most important criteria of a lubricating oil. The basic performance of machinery is based on the viscosity of the lubricant. Viscosity is, if you like, the resistance to the flowability of the oil. The thicker an oil, the higher its viscosity.

Multigrade oils work by having a polymer added to a light base oil which prevents the oil from thinning too much as it warms up. At low temperatures, the polymers are coiled up and allow the oil to flow as it's low number (W number) indicates. As the oil heats up, the polymers unwind into long chains which prevent the oil from thinning as much as it normally would. The result is that at 100°C, the oil has thinned only as much as it's higher rating. Think of it like this: a 10W30 oil is a 10-weight oil that will not thin more than a 30-weight oil when it gets hot.
The viscosity index of a lubricant is an empirical formula that allows the change in viscosity in the presence of heat to be calculated. This tells the user how much the oil will thin when it is subjected to heat. The higher the viscosity index, the less an oil will thin at a specified temperature. Multi-viscosity motor oils will have a viscosity index well over 100, while single viscosity motor oils and most industrial oils will have a VI of about 100 or less.

sorry had to get that out of my system

Icemark

A couple of things:

Temperature has the biggest thing to do with it.

If your average temp when starting/driving the car is:

Above 0F you should be using 20w50.

Below 30F you should be using 5w30.

10w30 should be used only if you temp average is between -10F and 80F. You should not be using 10w30 if your outside temp is above 80F in a rotary. You are just asking for oil failure and ash/carbon build up if you do.

Never ever ever use 10W40 or 10W50 in a rotary...there are too many additives to get that viscosity range.

Too many people confuse what works fine in their S10 pickup to what oil a rotary should use. Two different engines with two different shear loads. Remember a 4 stroke engine only has a 50% duty cycle, while a rotary and two stroke has a 100% duty cycle.

BTW: the Pennzoil thing... Both Pennzoil and Quaker State were Paraffin based oils only a few years back. Paraffin oils had a tendency to cause more sludge in higher revving motors as found in most imports. This was a bad thing. But both companies have been buying oil now from alternative sources so the amount of paraffin based product is considerably lower. That’s were the don’t use Pennzoil or don’t use Quaker state comes from.

I personally use Castrol in all my cars with the correct weight for the engine, not because I have used 10W30 in my truck forever.

As too synthetics, both Mobile One and Royal Purple have burn off rates very similar to a conventional oil and would be fine to use in a Rotary, however, the extra cost does not generally justify using the oil unless you have special circumstances, such as you have a racing motor that you don’t want to tear down after each race, or you need your motor to last to 300k miles, because you are too cheap to buy a rebuild at 200k miles instead. Or you are using a turbo or some other forced induction. You will not gain any extra HP using a synthetic!

You would not want to use any other Synthetics than those two at this time. You of course would still want to do your oil change every 3k to 5k miles even if you are using a sythentic.

tesla042

Also, switching to/from synthetic in the middle of an engine's life can promote a little bit of leaking. Since the synthetic oil's molecules are smaller (..why it's better in the first place), they may end up finding spots to leak out that conventional oil wouldn't.. Not the biggest of deals, as it would probably be very small..

-Tesla

StarionX

This seems a little contradictory... is it just a typo in the numbers?

ROSHX7

I think this is the EXACT reason, that when I used PENNZOIL 100% SYNTHETIC last oil change (for the very 1st time), I was using about 1 whole liter of oil every 2 weeks!!!! Either it was burning off or leaking somewhere. But for the current oil change I went back to REGULAR PENNZOIL and now it doesn't burn off nearly as much...like I usually add a liter about every month now.

JerryLH3

iTrader: (11)

No, it probably wasn't. There is usually overlap between in these type scales. Proof is in the owner's manual with the recommended viscosity of lubricants in the back. You will see their is overlap.

Icemark

No typo... as JerryLH3 says there is a bit of an overlap. And I am posting that based on average temps.

ocassionally at 0F low is different than everyday at 30F as the high.

turboshjosh

i live in florida and drive a tII, i'm currently using 10w-40 castrol gtx, is this bad?

Rotorious7

iTrader: (1)

i have been using AMSOIL since i found out about it. In the gearbox, diff and engine. One thing though, at first you will notice a big difference when switch from conventional oil. Synthectics are higher detergent oil and protect under extreme (dissapate) heat. You will notice a little more burnoff at first, that is usually the removal of sludge build up from petroleum base oil. Once your car has run synthectic for a while the burnoff will slow as the new oil starts to get compatable with the seals in your engine. The best oil are rated in order from Amsoil, Mobil, Castrol, etc. Amsoil been the most expensive because of its ability to last 25,000 miles and beyond with special bypass filters and test every so often. No true racer would ever run at this lenth but the protection in knowing is always comforting

thomasmeisch

Manufacture Chevrolet recommends 5W-30 in it Blazer, it still running at 230,000

Manufacture Mazda Recommends 10W-30 for N/A and 20W-50 for Turbo.
My '89 has 112,000 on her and runs like it did 12 years ago when I bought it.

There is no confusing an S-10 with a RX, but in a stock set up the ouside ambient temp is the factor not the engines duty cycle. As you pointed out.

Your few years ago was 1987-1991, in 1995 Penz switch to a purebase method of refinery that clear out 99.99% of the impurities in oil even pariffin. The build up you speak of was rare and limited to high performance.

So pick your brand, ask your local Rotory man or Mazda Dealer what is recommended in you area of the country and be happy

Icemark

Actually the numbers are from under the hood on the factory hood NA sticker and the factory shop manuals other than my recommendation away from 10w40 and 10w50, which is based on both the petroleum institutes and BR racing burn and flash test results.

Again the factory sticker says do not use 10-30 at above 80F. Whoops, I just double checked it says don't use 10W30 above 85F on the factory hood sticker. Either way the 20W50 will provide a better temp range if your tempatures are above freezing.

But you are correct in that the temp outside makes the biggest difference and you should pick you oil accordingly.

thomasmeisch

I dont have a sticker under my hood, Just the belt diagram. Damn UK RX!!!!!!!!

thanks for the debate though

kevinmfaust

You should not use 20w50 oil in a turbo engine. Yhe oil is too thich to flow through passages in the turbocharger. That is why EVERY turbo engine built calls for 10w30 oil in warm temps and 5w30 in cold. 20w50 is also way to thick at start up.
Kevin

ROSHX7

Yeah, that was my EXACT same thoughts too. The turbo oil feed line is pretty small, so thicker oil would flow somewhat harder through this line, so you'd want a thinner oil for sure. 10w30 seems like its the way to go, plenty thin at startup, thick enuf for under heat.