olddragger

iTrader: (3)

the only easy way to increase the oil flow is with the bypass mod.
While i totally agree with RG on many points, i respectfully disagree that the S1 renasis doesnt need more oil flow.
Ash has pointed out the differences in the rotary engines over the years and oil pressure is one of them. The S1 has the lowest oil pressure at the hp/rpm range it has.
Mazda changed the internal flow and the pressures for the s2 model.
They also changed the oil filter bypass pressure.
The s1 engine has shown a high percentage of front bearing wear --among other stuff--at less than 60K miles. I am talking through the copper here.
The best engine builders that I know of suggest a thicker than recommended oil viscosity, e pellet mod and to increase the flow (via oil pressure regulator upgrade). These upgrades to the best of my knowledge have only recently came to light and it is too early to have engine tear downs to check.
Oil pressure in itself is not the issue at all. Its film strength, flow and temperatures.
There is some talk now about the e shaft not being able to handle 9K+ rpms.
The engine needs more balancing in order to spend a good bit of time in that rpm range. I redline ( i have a sc engine) at 7.5k i will go to 8.2K at times(rare)--but na folks are advised to not go pass 8.2-8.5K without more balancing.
Now to try and crank this R3 deal I found--talk about flooded! And I cant get it out of my hilly backyard to pull start it. I have cussed out every tree in my yard.
OD

rotarygod

I didn't say it doesn't need more oil flow. I said more and more isn't better and better meaning at some point you don't need more. The Renesis oil passages are pretty bad compared to the older engines.

In regards to viscosity, don't get caught thinking that a thicker colder oil will protect bearings better than a warmer thinner oil. It won't. What I was saying in regards to that was that when the oil is cold, it relies on it's viscosity to protect the bearings. When the oil is hot, it relies on the formulation and sheer strength of the oil to protect the bearings and other components and these are independent of viscosity. Viscosity on it's own does not necessarily protect well as you can still have very low film and sheer strength. You can have a thicker oil that doesn't protect as well as a thinner oil. There are many examples of this. Synthetics vs conventionals being a prime example.

DarkBrew

Yeah, exactly what I was thinking about on the way into work as my oil temps refused to climb over 75C
Water temps were 80C in five min and held 85C most of the trip (30 min) @ ~125km/h ~4000 RPM
I'm in the range for the pellet to open but it's hard to say if it does.

Edit: I forced the oil over 80C with some higher revs then hit the highway... the temps drifted back down to 75C on the highway.

Looks like I'm making some oil cooler covers...

Edit:
HiFlite999, how about adding the requirement to monitor oil temps in cold weather and adjust the cooler capacity as required to operate in a reasonable range. I'm thinking about oil cooler covers similar to what's used in aircraft for the same issue

HiFlite999

iTrader: (2)

The bypass mod only increases oil flow over stock at pressures above where the stock bypass opens (~75 psi). For warm 5w-20 oil, this is around 5k rpm. Once the bypass is open, increasing rpm does not further increase oil flow. Now suppose a true believer puts in 20W-50 cause he heard it was a good idea (and he sees more oil pressure at idle). Instead of opening at 5k rpm, the valve opens at 4k rpm, thereby reducing oil flow compared to the 5W-20 from that point up. Now suppose the oil is cold on top of that, and the bypass opens at 3k rpm. Houston, we have a problem. With the mod (or the Series II), the bypass essentially never opens which means the flow becomes unrelated to oil viscosity or temperature.

I also rather suspect that 9k rpm is not a good thing to do routinely. One is the unscientific observation that a fair number of "I need a new engine" posts also include "but I ran it to redline once-a-day". The other, also unscientific, observation is that I feel a distinctive shake happening right before the car beeps the rev limit warning at me.

HiFlite999

iTrader: (2)

I have it as #11: (11) If you're driving in winter, particularly a lot of short trips, consider blocking off one or maybe both oil coolers with a piece of cardboard or foam to reduce water buildup in the oil. Monitor temps!

Most airplanes have air-cooled engines and many of those have what's called "cowl flaps", which are opened or closed to allow more or less cooling air to flow over the oil coolers and cylinder heads to keep them at acceptable temperatures. Could one do the same for the 8? Probably so, but with limited effect. Reports so far are that one really needs to close off both sides of the coolers to get the oil temps up significantly in cold weather which would be mechanically difficult to do 'the airplane way'. The real problem is that while there appears to be some thermal bypass valve involved in the stock o.c. setup, it doesn't ever shut off flow totally, and opens too soon to act as much of a regulator of temperature. Generally unmentioned too, is that the 8 has 50% more oil to heat up than most cars, plus the e-pellet issue and all the extra surface area represented by the coolers and all the lines running to and from them.

I'm pretty sure there's not a clean quick fix to this problem; it'd take some serious re-engineering.

DarkBrew

Sorry if I missed the reference.
I was looking at several oil cooler covers from aircraft, motorcycles etc.
The one I really liked was one with remote control. Too bad it was almost $400
For certain an oil temp gauge is a must for this car

snash22

I just purchased a 2004 RX8, it has 69K miles. Its birth date is March 2004. For the 8yr/100k mile warranty I have about 18 months or 31,000 miles left. I am likely to hit the 18 months first.

I am in a bit of a quandary deciding whether to try to help extend the life of the engine as discussed in this thread or if I should do the bare minimum maintenance hoping it fails. I would hate to extend the life of the engine and have it fail at 18 months. Conversely, I'd hate to just do the bare minimum maintenance and then have the warranty expire and then I'd be wishing I took better care of it.

My gut says to treat the engine right. But my wallet would sure love a free new engine.

HiFlite999

iTrader: (2)

I added a couple of things as follows:

[x4] [If you decide to eliminate the connection of the coolant lines to the throttle body, do *not* use the screw in the line trick to simply block coolant flow. That line goes on to the rear iron where it adds cooling to a critical area. Do a full bypass so that flow to the iron continues.

[x5] [I've read a couple of comments that overheating with heavy high-rpm operation can occur when a radiator hose collapses under suction. Perhaps heavier-duty hoses would help, or old-style "springs" inside the longer straight runs. I don't know if it's happening, but am recording the possibility for consideration].

The first is pretty clear. The second is ranked as a possibility. Many have commented how their temps really take off running sustained high rpms. Certainly max power = max heat, but should it be so non-linear? One blame given is the cavitation of the stock water pump at high rpm, with a fix of using the mazmart Remedy pump instead. A cavitating pump however, puts a limit on the suction seen by the hoses. No cavitation means higher suction, perhaps higher than the hoses were designed and tested for. I'd welcome any comments, discussion or data related to this point.

bse50

Temperatures spiking may be because of relatively slow speeds\flow through the radiator in the stock overly packed engine bay.
I say this because the issue disappeared after I stripped my engine bay while it was frequent with the stock setup+stock water pump (and a tad less with Mazmart's water pump). Now i have to tape my oil coolers during winter cruising.

9krpmrx8

iTrader: (46)

I can attest that when I replaced my coolant lines after 100,000 miles, that they were as soft and easily collapsible. The new factory hoses I put on were pretty stiff and rigid. So I could see old hoses collapsing easily.

Beodude

iTrader: (3)

I think most of the carbon comes from unburnt gas. If you think about the quantity of fuel that goes through the engine unburnt, and the amount of oil (burned or not) that goes through..... It would be hard to say that oil has much to do with carbon build up.

Also, I could be wrong, but when you lubricate things, stuff won't stick to them as easily. If your rotor housings are well lubricated, there wouldn't be anywhere for the carbon to "grab" onto, and it would go out your exhaust. That would explain the lack of gunk around the oil injectors....

ASH8

The issue is not Carbon on Rotor Housing surface it is the Carbon which only builds up on Rotor Faces and Apex Seal area, and lastly Spark Plugs.

Because of lack of lube, not only does the Apex Seal face wear unevenly, but carbon build up (from gas) restricts the very small movement of the Apex Seal/Spring inside Rotor's Apex as it runs around Rotor Housing.

The Apex Seal jams up with Carbon and usually sticks down hard with no springing movement.

No A S seating means no or poor compressions (1 of the 3 or 2 of 3, even 3 of 3 A S can stick in each rotor).

Best attempts to free them up is pouring excess AFT or 5W20 direct into Rotors and AS, or seafoam..IMO has about a 30% success rate, usually short term.

But for the average rotary user, you can not escape carbon build up on Rotors, it is just not possible, unless you are running only Hydrogen as a fuel.

Beodude

iTrader: (3)

I would imagine that premix and a good tune would go a long way to preventing all that stuff.

9krpmrx8

iTrader: (46)

I would almost like to put one of the those small surgical camera in through the spark plugs holes to see what it looks like in there in my engine after 25k with premix and the SOHN the whole 25k

HiFlite999

iTrader: (2)

It might be fun, but could one really see anything useful throught the spark plug hole. As I understand it, the real carbon action is more at the corners than the center.

It's been suggested too, that water/meth injection may, besides its other benefits, serve to clean the combustion chamber. If anyone has direct experience along this line, it'd be interesting to hear from you.

9krpmrx8

iTrader: (46)

Yeah I doubt you would see much depending on the position of the rotors.

ASH8

Huh, Whatever your spark plugs look like is a good indication of what your rotor condition is.

Plus you can see Apex Seal face and area around Leading spark Plug hole if you use a small light....but yes you do not see much at all...provided rotor is in the correct position.

Pre-Mix does not cure carbon build up, it just helps (mainly in lubrication).

9krpmrx8

iTrader: (46)

I dunno, I have changed plugs on many 8's, old and new and for the most part they look pretty much the same. Do normal plugs charts crossover to the rotary world?

ASH8

Sorry mate, don't get that one?

And exactly, the pretty much the same plugs mean pretty much the same carbon build up etc, etc.

Frankly this Red-line a day is a little confusing and a little BS, does anyone honestly believe that a few red-lines is going to clean up a rotor??.

Sure if you can drive around at 7000 RPM all day, it may prevent build up, but realistically it is the low RPM use which is the engine killer...as we know.

All the red-line does is help..I say help clean the **** off your spark plugs.

9krpmrx8

iTrader: (46)

I totally agree about the redline a day crap as well. I went through two motors and both were redlined regularly.

This chart, do you guys think it is the same for rotary engines?

Brettus

iTrader: (2)

Yeah , I agree as well . I would substitute "redline a day" with something like "don't drive like a granny" .

DarkBrew

+1

Driving hard does the following

1. Vastly increases the OMP flow
2. Reduces carbon deposits and may help to burn some off
3. Exercises the intake runner valves
4. puts a smile on your face and reminds you why you own the car

Cole33

What do you guys use to cover up your oil coolers in the winter? I have heard some people use tape, and just tape over them. I just wasn't sure if there were any other options.

The weather around here is usually between 20-30F here, with dips down to the single digits. I use the 8 as a DD, so I do make short 5 to 10 minute trips to school on a regular basis.

ASH8

Totally agree with 9K, Brettus and DarkBrew..

Don't forget I am talking Daily use of the Renny, not a track only car..

IMO, all of what you guys say....it is those who travel below 3000 RPM all the time are those that will kill the engine, not so much because of lagging or low RPM, but the fact you are not "exercising" the Engine properly as it was intended and designed for.

You need to use All the RPM bandwidth but keep the ultra high RPM stuff for track, otherwise you wont have a drivers license for long or even worse.

Again IMO you need to keep engine RPM above 3000, preferably 3500 and above for basic driving, the 3800-4k is a good one which will return "reasonable" economy and provided you exercise engine also a reasonable engine life...using your stick gearbox.

Another reason why Auto Renny's have failed, not enough engine "exercise", just constant low RPM with little variance..

SSV Valves not even opening, etc, etc.

It is all part of the FUN in owning a Rotary, too many want to compare to Banger engines, which also have limitations and issues that a rotary does not.

ASH8

OH, and yes 9K much of those Spark Plug pics and diagnosis can be crossed over to a rotary spark plug condition...frankly I can't see many that do not.

Unless you are running VERY Lean (AP), or another fuel source, or constant track use (above 7k), you wont see plugs as clean as newer piston engines of recent years, main reason being the Rotaries Engine Oil Burning and Pre-mix if you use it, will add after-matter to the Spark Plug.