Okay, this being my first time owning an Rotary based vehicle I spend alot of time reading different articles. And there are plenty to read. I just want to confirm this. DO NOT USE synthetic oil in FDS3? Use the good oil 25w-50 oil and change often? Thanks for confirmation.

 

Sweet Jesus. There are about 500 threads on this board on this topic.

 

Yes I know, the more I read, the more confused I am getting. Maybe it's just my brain fighting with me...

 

Change you oil every 2-3k. Beyond that, it really does not matter what oil you put into the car assuming its weight is close to factory specs. I have not seen a single piece of objective evidence that has demonstrated the superiority of one oil over another in practice. People who think a particular brand makes their car drive more smoothly than another brand are delusional.

 

I use regular oil. You can use synthetic, Mazda only recommends conventional oil like Castrol GTX. Many people swear by synthetic but it is also not necessary. Some have proven that the synthetic does burn and will not screw up the engine (Racing Beat is fine with royal purple and I think Amsoil) but again it is not necessary. If you change it often it really does not matter. Look into adding some indemitsu pre-mix to your gas. http://www.rx7.com/store/rx7/fdengine_maintenance.html

Most people have an engine failure on the FD before they ever have a chance to wear it out due to wear and tear where a synthetic might have helped some.

 

Reportedly synthetic oils degrade carbon seals (turbos) - other than that, you should be fine

Then again, these engines contaminate their oil so fast I don't think synthetics offer much of a benefit unless you're tracking the car. I run Valvoline VR-1 SAE 60 (straight weight). Within a relatively short time, it thins out to a 30 weight (verified by oil analysis).

 

There has been objective data. What about the used oil analysis thread? We don't have a very high sample but its better than nothing and not data I would discard.

I'd say change your oil every 2k max or 3 months whatever hits first. If your oil looks dirty or watery when you check the dipstick, change it. You should be checking your oil fairly regularly.

 

Note the "in practice". While I don't doubt that different oils will generate different wear profiles that can be seen in an analysis, the apex or coolant seals will have failed on an FD engine well before any any wear differences could be remotely of practical consequence.

A 3 month oil change interval would equate to me changing my oil every 300 miles! If I had a car that required that type of effort, I would sell it.

 

I use vegetable oil in my FD. you only have to change it every 2 years or so

 

I don't know what it is but my oil dirties up or gets watery really fast. I have to get it changed right now and I don't have many miles on it at all. I think the oil was changed for the Carlisi bbq. My oil was definitely dirty from the year or so it was at the bodyshop thats for sure . I also remember my oil being clean but really watery another time (30w). OIL CHANGE!

 

Get it tested next time. You need to know how where the viscosity stands after 2-3k miles, and what your % fuel dilution is (which is generally what causes the "watery" consistency - that is, loss of viscosity - and smell). 10w-30 doesn't cut it in these engines - I was seeing indicators of excessive bearing wear

https://www.rx7club.com/showpost.php...8&postcount=42

 

You need to spend some time on BITOG. Several members on S2KI also post UOAs all the time, they are very informative. Most modern synthetics are pretty good, but to say there is no difference in performance with standardized wear tests and/or relative UOA performance is simply ignorant.

If ANY street engine needs regular oil testing, a turbo rotary is it....

 

Fuel dilution is the main problem turbo rotary's have. Change it regularly and you should be ok. I change mine every 1k miles or whenever it turns black and smells like fuel.

As far as what type of oil to use, just use what makes you happy.

 

My oil turns black and smells like gas within a couple hundred miles, depending on how much I'm on the boost. Changing it every 1k is a bit nuts if you ask me, and it can thin out well before that time, anyway. Running 50-60w racing oil anticipates thinning, and seems to be a better overall solution. The oil thins fast when exposed to fuel, then reaches an equilibrium point where it doesn't seem to get much worse with additional mileage, at least that's my experience after running several of these tests now.

You don't run the same viscosity in these engines you run in a Civic, I think that's axiomatic.

 

Everyone forgets this was gospel as of TWENTY+ years ago. Things have changed.

there are many many people out there successfully using Mobil 1, Idemitsu and many other synthetic oils.

 

today

 

I would not recommend changing your oil once every summer even when you running Mobile 1 20W-50. That is the oil change interval the previous owner was using, and now having torn the engine apart to "fresh'n it up" I have to replace all the bearings, and a couple cast irons....


On a positive note, non of the bearings spun...................... yeahhhhhhh sythentic ~

 

Yep.

 

i run non synthetic valvoline. no oil related problems yet.. guess you cant really go wrong as long as you keep up on oil changes.

 

This argument is dumb. The fact is some rotaries last well over 100,000 miles - even 200,000 - with original apex seals. The lazy/apathetic person just throws their hands up in the air and says, "well it's going to blow anyway - f* it". I've spent alot of hard earned money on my engine and I'm going to do everything possible to keep it healthy for a long time. The best way to do this is 1) never run more boost than you can reliably support, 2) change the oil every 2k and use a straight weight racing oil, expecting fuel dilution because you know it's going to happen with a turbo rotary, 3) pre-mix a high quality synthetic two stroke oil and/or inject water to keep the rotor faces from getting carboned up. Yes, coolant seals can fail at 70k, but they are relatively straightforward to replace, and some of the newer technology seals promise longer service life.

I've already seen a dramatic reduction in bearing wear by just switching from 10w-40 to VR 1 SAE 60. You don't have to resign yourself to accelerated wear in these engines.

 

Not trying to thread jack, but I've been running Castrol GTX 10w-30 for about 8 months. However, I just moved to Italy and they don't even carry that here. I got choices of Mobil 1 Synthetic and some Semi Synthetic stuff and conventional oil from no name brands. What do you guys recommend I do? If i make the switch to Synthetic or Semi-Syn, can I just switch during an oil change? Will it be ok?

 

^ Nothing wrong with that.

thewird

 

Read again. Apex seals or coolant seals. I would bet a lot of money that less than 1% of the FDs make 200K on an original engine. I have never heard of anyone doing it.

Fact: Turbo cars generate more heat.
Fact: More heat kills coolant seals.
Fact: Coolant seals blow out before oil related wear requires a rebuild.

 

This is true only if you consider removal and COMPLETE disassembly of the engine as "straightforward".
IMO straight 60w would not be appropriate for many areas and seasons in this country for a streeted car. IIRC, VR1 retains it's ZDDP. That may be more of a contributor to reduced wear than viscosity.

 

I agree with using reg oil if you change it often anyway and/or if you don't track the car. I have tested mult oils at blackstone and royal purple in my case had promising numbers and didn't break down as fast as mobil 1 syn and castrol gtx. But buying oil at 7.50 a quart just for me to change it at 1500 miles is a waste of money and im sure reg oil would protect the engine/turbo just as efficiently as me using an expensive syn.

Now if I was gonna track the car, a good syn is going right into the engine. No doubt about that. And yes a good premix is recommended if you go syn.