Stationary bearing wear appears to be due to lack of lubrication, perhaps on start up. Heavier oil would not help this situation. Based on my observations with my Defi oil pressure and temp gauges the RX8 takes a tremendous amount of time to get the oil up to temp. The stock gauges indicate that the engine is up to temp when it is far from it. Many RX8 owners are pushing their cars hard before the oil is up to operating temps. IMO 5w30 would help protect the bearings on intial start up when most of the wear occurs. I will change over to 10w40 in the summer for track event but will change back to 5w20 for the colder monthes. BTW I use RP oil and have the mazmart wp.

 

And maybe a little machining on the block so the bearings line up better?

Ken

 

Wow.... a lot has happened since I visited this thread last. Took me over 1/2 hour to read and look at all the pics. Looks like I'll be changing from 5w20 as well and will start running 5w30.....at least for now and may go up to 10w30 for Summer.

 

I dont know if this link would be useful to anyone but it helped me a little to the understanding oil and what they use to make it

http://www.ecoadvanced.net/pdf/motor-oil-bible.pdf

 

and i just bought about 20qts of 5w-20 o well

 

my only problem with this argument is that higher viscosity doesn't automatically equal more protection...

 

It could be but if you already have a more heavy oil that is in there, it would provide that buffer instead of the lighter oil just being "pushed out". It also makes sense for "everywhere else in the world" that possibly a 10w40 or the like is recommended because of the 13B engine having a higher temperature output. The wear on the bearings doesn't necessarily have to be just from the startup. It could also be from the oil being broken down more quickly because of the engine's higher temperature output too.

I was told by a professor within the last year that the strict standards (Tier II emissions) that California has affects most states in the US also because Southern California has about 10% of the car buying power in the world.

 

Viscosity people refer to is "thickness" because of the oil weight and look that it "appears thicker" as you get to higher numbers from 5w20 to 10w40. But viscosity really is the measure for the resistance of the fluid before it "breaks down" or reaches it's threshold to be quickly broken down (i.e. extensional/shear stress on the fluid, higher temperatures, etc.).

So going a higher viscosity oil prevents the oil from hitting it's stress point. If say 5w20 is being broken down more quickly because of the conditions, the oil was rated to last 3,000 miles, now is being broken down quickly and now only lasting 2,000 miles. Once that oil starts to degrade, you would have more of a wear because of the oil not able to lubricate the gears anymore.

 

i can easily argue there are 5w20 oils out there that beat the pants off of 5w30 oils out there

 

From what I've seen in all the pics nothing is abnormal in the wear department. I have seen bearings like that for years. The amount of wear on them is so minimal. As to measured with a micrometer.
One thing you must remember is that the eccentric shaft flexs a small amount on the ends. Sustained high rpms will do the same to the bearings as will the oil, or lack of it on start up.
I see an engine that looks normal for it's life. If not, very good.

 

You'll always find some companies producing better quality items than others. Some adhere to the bare minimum standards to call it a 5w20 oil. Other companies will add the extra umph or mile that makes them the "recommended" choice.

 

That statement gets to the core of many wear issues. It's something to remember for all engines, not just rotaries. Good observation.

 

I personally believe that is the BIGGEST problem for a big majority of car owners..

Forget an immaculate service record, use of synthetics or if you change your oil and spark plugs every 100 miles.. people need to get it in their heads that engines need to properly warm up (not just for old cars)..

Even 15 seconds idling makes a huge difference compared to one that gets driven off immediately.. 3 minutes if possible.. and at least 10 minutes before it gets heavy load or high-rev action.

 

It takes a while for engine oil to warm up, especially for places like NYC, if you have some Temp gauge installed like me, you'll know that it takes REALLY LONG time for oil to get to even just 75 Celsius.

From now on Im going for 5w40 and 0w30. I'll save the 5w30 for my other cars.

 

another point for getting REAL gauges.
OD

 

How long is really long? How many minutes after water temp is warm?

 

Does 30 minutes sound long ?

its *pretty long* for me.

When the outside temp is around 15-30F, it takes around at LEAST 30 minutes, well, it should be first 3 minutes for warm up idle, about 15 minutes of easy driving, then the rest is regular driving. but sometimes I still cant get it to 75 Celsius.

30-50F , about 20 miutes.

50-70F, 10-12 minutes

Anything above, Within the first 10 times.

Water temp gets up much faster (as always), With the outside temp around 15-30, maybe 15-20 minutes. **** sometimes I see the water temp gauge drop back down (!!!) to 75-ish Celsius, if I go fast enough, then the Thermostat gonna close and I just wait again for it to open up.


I think the biggest problem is that *most* people dont do *warm ups*. Even if the outside is warm you should always let it idle for a bit before you move out.

I seen ******** just get on and drive their car away when its like 20 degrees outside. I was like what the hell. Good luck with the car. I be laughing if I see his car *dead* on the side of the highway.

 

errr.. no.. viscosity is just simply the more viscous something is, the more stress it takes for the liquid to shear.

 

We used to see bearings looking like this at 180 to 200k. The front bearing is wiped out (Beyond being re-used). It's down to the copper, the last stop before the steel. This is not good. The reason I made the controversial statements regarding viscoscity at the beginning of ths thread is due to the number of these engines (Renesis) we've built and the common observations vs rotaries from the past when Mazda was recommending 20W50.

Paul.

 

Of course rotaries from the past didn't turn 9k routinely as street cars and this motor has seen track time. This one has been taken care of and used 5W20 RP synthetic for 40k miles or so. What we've seen in the others we've built still leads us to recommend 10W40.

Here's the important illustration again on this motor.

Paul.

 

Very good reading. Thank you.

Paul.

 

Would your recommendation of 10w40 apply to cars w/ Forced Induction as well??

 

Paul,

I again would like to thank you for taking time out of running your business to post the photos and your comments. Unless you plan on making a “ in conclusion “ post I do have some follow-up questions. As an owner of one of Rick’s ‘children’ I want it to last and perform as long as possible.

Viscosity issue aside, is there any indication the use of Synthetic oil had any positive / negative effect on my former engine?

Did my use of pre-mix harm or help extend the life of my motor?

Was the bearing, Apex Seal issue the cause of my recent oil leak issues at the track? But driving around town (under 7,000) not an issue because of the reduced engine load?

Based on what you saw do you think the compression test I had at 98,000 was preformed correctly?

What would have happened if I didn’t get one of your engines? Was it just a matter of time before I either broke an Apex seal or had a bottom end problem?

Just one more thing from me if you plan on keeping your RX-8 a while find a shop that knows something about rotaries and has no connection to Mazda USA! If it wasn’t for this site I wouldn’t have found Paul & JPR Imports. I would have giving the dealer $2,500-$4,500 dollars and they would have never found the Apex or Bearing issue! It’s a sad fact but Mazda service is not the best thing if you plan on keeping your car for a long time.

 

Paul that's not bearing wear. That's called clearancing!

 

Does our oil cooling system have a thermostat built in? If not, some cardboard (or something slightly more visually appealing) in front of the oil coolers should do wonders for oil warm up time...

Care to elaborate for the rest of us?