lord wither

Ok, I just changed the oil in my 87 rx7 gxl, I used Mobil1 15w50. I think this is good oil. Anyway, I noticed after I changed the oil that I have a lot of air bubbles(foam) on the dipstick. Is this normal, or is their a problem that I need to locate? There was no discoloration with the old oil, just foam. Any help would be appreciated

EmbassyBlack

mobil 1 is ****

TongassT

Wow, your point on the subject is both non-biased and informative, packed full of evidence to support your claim, and also on topic of the original poster! Post of the year nomination!

I guess I should drain all the mobil 1 out of my motorcycle, truck, and car.

Anyway, for the OP, Could be something as simple as condensation, especially if you have removed many of the emissions and the crankcase is vented to atmosphere. Is there water in the oil when you drain it?

kenny senter

I wouldnt run synthetics. The rotary engine is designed to run on regular oils, not synthetics. The reason being is that the engine pulls from the oil metering plate and does burn a certain amount of oil as it uses this oil to lubricate the apex seals (this I learned from reading this forum. It may not be totally correct, but the gist of what I'm saying is true). Synthetics dont burn as well as regular oils and will leave behind heavier deposits, eventually enough to mess up your engine.

Use regular oils, not synthetics

somebody5788

And where did you read anything about synthetic's in this thread?

misterstyx69

iTrader: (142)

Just look Down after the "post quick reply" ..When someone asks a Question 9 times out of Ten it has been covered.So Best bet is Post the Question,then look down there for related Threads..I'm not one to Run Synthetics in the engine,if the OMP is working.The Omp puts it in the Internals for Lube,and is Burned..the Regular "Dinosaur" oil has done my engine for 191KM so I stick with it.sytnthetics,In my opinion "may" have some Additives,and to be on the Safe Side,I don't care to put them into the Rotor housings to be burned up...If I had a "ultimate Engine lube system",it would consist of Synthetic to Run through the cooler and Two stroke to Go into the OMP to Lube the Internals...OR Premix.

Evil Aviator

Was the foam only there right after filling the engine with oil, or is it still there now?

Also, FYI, the synthetic oil isn't going to do anything special for your engine except protect it better in an extreme racing environment and allow for better cranking in cold weather. For most people on this forum it is not worth the extra money.

V
V
V

Turbonut

iTrader: (1)

From the FAQ's:

Can I use synthetic oils in my Rotary engined car?
Yes and no. Mazda officially does not recommend the use of synthetic oils in rotary engines, however, long term and racing use has shown that the better synthetics (Redline, Amsoil, Neo, Royal Purple, Mobil1) are perfectly fine to use in a rotary engine, and will generally result in a 1 to 2% horsepower gain. However use of poor quality synthetics (like Valvoline, Castrol Syntec, Havoline, Etc) will result in build up due to high ash content left from these oils when they are burned. It is believed that is why Mazda did not recommend synthetics, because the couldn't pick favorites.

Other notes:
The Mazda Factory racing departments recommend and use ‘synthetic’ oils including the winning 1991 Leman’s 20-G 4 rotor Mazda 787B.

MazdaComp USA printed manual (now Mazdaspeed) recommends the use of synthetic oils for racing conditions.

Redline, Amsoil and Royal Purple Synthetic Motor Oils have been used in rotary engines (both race and street) for ten plus years with excellent results.

Most Synthetic Motor Oil is compatible with the bearing material, sealing elastomer's, and combustion seals used in a rotary engine

lord wither

Nope, there was no water in the oil, but I did smell gasoline. There is no air bubbles now that I have let it sit for awhile.

lord wither

I have done a lot of research on the different kinds of oils. And Mobil 1 is one of the few "true" synthetic oils that have little to no ash deposits left behind. Ammsoil and Royal Purple are better, but more expensive.

Icemark

If you have the money running a good quality synthetic is perfectly fine. kenny senter does not understand oils if he thinks that synthetics don't burn as well as regular oils. Every synthetic made burns at or less than 500F... considerably lower than the actual combustion temp in a Rotary engine.

Now, high ash oils should not be used, regardless of if they are conventional or synthetic.

anyway back to the foam in the oil. Foaming oil generally is either caused from Cavitation in the oil pump, or breakdown of the oil by being mixed with either fuel or water/coolant

Or missing emissions equipment.

If your emissions equipement is intact, then I would first be looking at diluted oil (you mentioned a gas smell). Change the oil and send a sample of the oil off for testing.

Evil Aviator

OK, that is what I thought. It is normal to get some bubbles on the dipstick when you first fill the engine with oil. If you notice bubbles from now on, then it is probably caused by one of the reasons mentioned above in Icemark's post.

Sorry to tell you this, but Mobil 1 was sneaky and changed their formula. It is no longer made fully from "true" synthetic Group IV PAO base stock. Here is their official response to the question, which dodges the issue in a manner that may remind one of Bill Clinton, lol:
http://www.mobil1.com/USA-English/Mo...Base_Oils.aspx

JReed

iTrader: (18)

i use royal purple and its works excellent

Slowride R7

I have been meaning to ask this question,

what about the high mileage oils that help seals stop leaking somewhat.

Would these seal conditioners be good or have no effect on the apex seals?

I have used HM Pennzoil with great success in my wifes 328 with a leaky oil pan gasket.

Icemark

In most cases, high mileage oils simply are regular oils that have additional amounts of Zinc in them. Zinc in oil really only helps if there is direct metal to metal contact. If the tolerances in the motor are correct, you will never need or use the extra zinc. In a rotary motor (and some high reving piston motors), additional zinc can lead to plug fouling. You generally want to avoid oils that have more than .15% (by volume) in rotary motors. (Castrol GTX 20W50 has about .12% as a reference, while Kendal GT-1 Hi Mileage and all Valvoline High Mileages oils have around .16%).

Some also add gasket swelling compounds which often help leaks, but at best is a band aid for problems that will eventually resurface.

So if your motor is in decent condition then it probably is a waste of money all together.

lord wither

That is no good. I will definately get Royal Purple or Ammsoil from now on.

lord wither

Ok, first of all what is Cavitation? And secondly, where would I send my oil to have it tested?

kenny senter

looks like I misinterpreted what the FAQ had said about synthetics, obviously. My apologies.

Carry on

Eple

I have Motul 6100 Synergie Synthetic in my car.

Evil Aviator

While Group III is actually a bogus synthetic, it is still better than conventional oil, so what you now have in your car is not bad. While it is difficult for me to keep up with all the industry changes, I am pretty sure that Royal Purple and Amsoil are based only on Group IV. There is a lot of debate on the subject, but some consider oils which contain Group V base stocks (Red Line, Neo, and Elf) to be better for racing. However, like I stated earlier, you are most likely wasting your money buying synthetic engine oil, as I assume you are not a professional racer because you (or your crew chief) would already know this information. For street cars, I do recommend synthetic oil in the transmission and differential where most people can actually feel a difference, and the drain intervals are much longer making the extra cost easier to justify.

Oops, I said something nice about Elf. Now SpooledupRacing is going to find this thread and try to sell everybody a case of Elf oil.

Cavitation is when the oil pump is operating at too high of an rpm, which causes the formation of bubbles (cavities) in the oil. This should not be a factor on a stock engine. If you have a high-rpm race car, then you need under-drive pulleys to keep the water pump and oil pump from cavitating.

A good auto shop should be able to take a sample and send it out for analysis and interpret the results for you. Otherwise, search the internet for "Oil Analysis", and I am sure you will find several businesses with do-it-yourself kits.

Actually, you were correct... as per 20 years ago. Some of the older forms of synthetic oil did not burn properly and created striations on the rotor housings. Rather than list the good brands, Mazda just issued a blanket statement to not use any synthetic oil in the engine.

lord wither

I appreciate everybodies input to my question. Thank you.

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