rotarygod

The biggest problem with the radiator on the RX-8 is that air can't flow through it very easily since it doesn't vent well out of the engine bay. It is too congested. The oil coolers suffer from the same issue and compound it in the when the car is not moving there is no airflow across them since no fan is pulling air through them.

olddragger

iTrader: (3)

cant cool without airflow.
and the oil will follow the coolant. Not so much the other way.
OD

invasion08

iTrader: (7)

Unless you install a fan behind your oil cooler. I know this product was not a big hit with RX8 owners.

REDRX3RX8

I wouldn't try to get this; the qualifier here is "oil wetted parts", and catastrophic damage; not worn seals or rings.

Your renesis will fail from worn or broken apex seals before 300k miles so in theory everyone with rotary could get this deal.

They even list internal parts examples of crankshafts, but no mention of EXCENTRIC shafts.

rotarygod

Unfortunately what is popular and what is the right thing to do aren't always the same thing. A fan as well as way for air to escape from behind those coolers would be optimal.

ctsellersjr

i'm running castrol edge in my 8 and its running pretty good i'll be changing to royal purple after this oil change. just wanted to make sure my 8 wouldn't blow up from changing to syntec

9krpmrx8

iTrader: (46)

Why are you changing? Just curious.

rotarygod

Castrol is one of my 2 favorite conventional oils.

Nubo

I'd like to. Any links to substantial evidence?

Apart from 2 oil changes I've been running Mobil 1 synthetic in my 2004 going on 7 years now and running Marvel Mystery Oil premix for the last 4 years or so. I continue to await the imminent demise of the engine.

Personally I find the oil debate fun but probably a major misdirection of energies. Compared to even the average piston engine, the longevity of the Wankel is marginal at best. A 100K Renesis is a Methuseleh unless you do mostly highway cruising. Enjoy the unique advantages of the rotary. Durability is not one of them. I reckon more than likely you could siphon used oil from the Jiffy Lube and stand a good chance at reaching the average life expectency. That is, there are other factors at work that have a larger effect on rotary life than your choice of lubricating oil.

Brettus

iTrader: (2)

finally - some sense in this thread !

ctsellersjr

true true hey orange!!!!

rotarygod

This is completely false. The rotary engine itself is inherently more reliable than a piston engine. The problem is that you are basing your opinion of it on a particular rotary engine (Renesis) that lacked PROPER lubrication and as a result led to issues. It wasn't an engine issue. It was a lubrication issue.

See above. Improper lubrication doesn't care what type of driving you are doing. If the engine is turning and there is inadequate lubrication, it will ultimately lead to problems.

Again you are basing your opinion on an engine that has a known lubrication problem. Please don't tell me that the FD RX-7 engine was unreliable. It has inadequate cooling and a **** poor turbocharger system. The engine was not inherently to blame. They just didn't keep it cool enough. I have NEVER EVER had a rotary failure and I beat the crap out of them. Their inherent reliability was what allowed them to be so successful as race engines.

You go ahead and try that and report back. Someone who doubts the importance of lubrication should have NO problem in doing this. You are a hyppocrit if you DON'T do this now that you have said this and then report back. Put your money where your mouth is or don't give advice! What's it going to be? Store bought new oil or only used from Jiffy Lube? No excuses.

This is true. You could run it without coolant, run through a sandstorm without an air filter, you could fire off a .50 cal round at the engine block, or you could run it off of a cliff.

REDRX3RX8

Hey, I'm not a piston engine fan myself, but the Chevy 283 v8 was known for going 250k miles in 1965 with the marginal oil before much antiwear additives were put in.

Many Chevy drivers with the 350 v8 in Suburbans or work trucks have put over 500k miles on those engines.

The simple VW aircooled engines have also gone near 1million miles.

So what is the most miles on a Mazda rotary engine of any year?

Or to the point, whats the most miles on any of YOUR rotarys?

That might be a test?

Brettus

iTrader: (2)

Agreed . But a street engine is not a race engine and for the average rotary owner that just goes to work and back the rotary is inferior to a piston engine from a reliability standpoint . Maybe if we burned a fuel that didn't produce carbon - that would change .

Your experience is hardly typical and not relavent to what the average owner experiences.

rotarygod

^Excuse! Nice try. Next...

rotarygod

I've had a couple over 200K at the time I sold them. I've never held onto one long enough to go a million miles. Please don't give me the excuse that many piston engines have gone over that too.

Brettus

iTrader: (2)

Burning petrol creates carbon
Carbon in a petrol engine has a hard time doing anything that prevents the engine from running .
In a rotary engine carbon causes sticking apex/corner/side seals . Reducing compression on an engine that requires good compression just to get started .

So : unless you drive it like you stole it , carbon will build up eventually lead to poor starting .

This in turn puts the rest of the starting system into high stress mode leading to , draining the battery , stressing the starter motor , fouling the plugs etc.


All of which we see here on this forum on a daily basis .


Notice I didn't mention lubrication once ?

rotarygod

Carbon is mostly caused by the gasoline. This is true. What does that have to do with the oil or rotary reliability??? I have seen many engines that had huge amounts of carbon in them that didn't fail and so have thousands of others. What usually happens is that the intake valves on 6 port engines get stuck shut. The engines keep running. I've personally had a least 2 spark plugs fail and had their ceramic elements break off and fall through the engine yet they keep running.

The rotary engine is one damned tough little machine! You can hold it at redline for hours on end and as long as you keep it cool and lubricated it keeps going. That's why it is popular in small airplanes. It is reliable and durable. On the contrary, look up how many LSx engines have been put into small airplanes that didn't fail. If you find one, I'd love to hear about it! The pistons engines that are successful in planes for long periods of time are low rpm engines. A rotary will be held at 6K at full load for hours on end and will be just fine. It's durable.

The rotary is not tolerant to a few things. It isn't tolerant to poor lubrication, poor cooling, or poor tuning when under boost. When a rotary fails, it is almost always one of these things. Keep them cool, keep them lubricated, and keep them tuned well, and they'll go until the seals literally wear themselves down to the point that they don't seal anymore. Due to the mass of the apex seals this is somewhere above 300K miles in normal stop and go driving. It is much longer on the freeway at steady speeds. Take the engine apart, put new seals in it, and send it back on it's way. I know there are piston engines that have topped this in mileage but let's be realistic, how many people will ever see that many miles on their car and how many of those engines are making full power anymore anyways? The rotary is tough!

Brettus

iTrader: (2)

Found this interesting

http://www.rotaryresurrection.com/2n...nt_damage.html

And again . I agree with what you are saying about rotaries in high rpm/load situations . But I still belive the design is floored for the average Joe in his daily commute .

bse50

Brett did you receive my mail?

9krpmrx8

iTrader: (46)

It's funny because I go to a RX7 meet once a month and I have never personally seen a rotary with over 200k on it. I'm not saying they do not exist, but they are very rare (at least in San Antonio anyway).

Here at work I have a 2002 Toyota Sienna with 289,000 miles on it and it runs better than our 2006 Mazda MPV with 60k on it. Of course it has had 3,000k oil changes its entire life but it is a patient transport/errand vehicle and is driven by many employees and often goes week or more at a time without being started.

If you maintain them, most engines will last quite a while but the rotary has a history of generally being unreliable as a DD for a reason. But I will find out soon, I am buying my son a meticulously maintained FC with 40k on the motor (originally lasted to 80k) soon

Nubo

Agreed -- I was referring to the Renesis. And while some of its problems may have been lubrication-related I don't think that necessarily implicates the *brands* of oil people have used or even the quality of the oil. Synthetic or mineral -- if the problem was inadequate oil supply, all of the fury around the Synthetic debate is superfluous. And of course there are other enemies of the Renesis -- heat and Carbon.

These are all design problems. That the cooling of the engine is inadequate is just stupid engineering. The Carbon problem is inherent with the side-port design, and in the end were driven by emissions and efficiency requirements. It's exceedingly difficult to meet those with a rotary. The Renesis was hailed as the savior of the rotary concept. But the side-port design that enabled it to run more cleanly, also presents problems with clearing Carbon.


I was using some hyperbole to make the point that our fascination with engine oils is overblown. I use Mobil1 mainly because I'd used it on previous cars and saw the tremendous difference in engine cleanliness on those cars. I also think a synthetic may provide some marginal protection during extreme heating. Do I think it's the fountain of youth for the Renesis? No. And in fact, your source at Mazda think's it's the Devil's Oil. And yet my engine continues to survive -- so what is one to make of all the theories? My conclusion is that they're not very meaningful and that more attention should be paid to cooling and that pre-mix is probably a good idea. However, pre-mix will increase emissions and we get back to design constraints. Mazda engineers may agree that premix provides superior lubrication. But aside from the marketing problem that presents, the emissions issue takes it off the table.

Hyperbole is a fun way of making a point.

9krpmrx8

iTrader: (46)

^ Agreed. Normal people will think premixing is a hassle and I would assume if affects emissions but I am no scientist.

REDRX3RX8

Nubo,

+1 here, too!

ctsellersjr

wow lots of info to take in keep going this is very informational