Thanks Iluvrevs

Update:

http://www.flickr.com/photos/9krpmrx8/6595046221/

I have this as well in case you don't get them

http://www.flickr.com/photos/9krpmrx8/4390637228/http://www.flickr.com/photos/9krpmrx8/5405404751/http://www.flickr.com/photos/9krpmrx8/5407309753/

All good, did come across those and collected the results.

Im sooooooo confused on what oil to use after reading this thread... I have 87k on my car... not sure its the original motor as i got the car with 84k I need an oil change what oil should i use? also i live at 5000ft. alt.

I think the conclusion to draw from the data is that damn near any oil will do, leaning toward oils that retain their viscosity. Some of these oils definitely don't keep up the viscosity.

To me I think that means overpriced synthetics or cheap diesel oil. The 15W-40 cheap diesel oil works for me.

I sent in a sample 2 days before Christmas and added mail confirmation; apparently it's still sitting in the post office. :(

If your car is out of warranty or you are not worried about the warranty, then many people recommend an XXw40 oil. I have used Castrol 5w30 with good results and am still using a 5w30 because I am under warranty; several people on here use 5w40 or 0w40 synthetic. A lot depends on how you drive (street/track/stop and go) and environment (heat/humidity) and mods to your engine.

Most agree that the factory recommended 5w20 dino is too weak to provide proper lubrication/protection. My local Mazda dealer uses 5w30 Castrol so I figure they would have a hard time turning down a warranty claim for using 5w30.

The MOST IMPORTANT thing you can do is use a good quality oil (dino or synthetic) and change every 3000 to 5000 miles while checking often and keeping it topped up. Some poeple change their oil more often, few would recommend a greater than 5000 mile OCI althought the manual says up to 7,500...:dunno:

I use 20w50 in my 1979 12A motor.

Looking at the analysis I did and had posted here via an Excel pivot table its not real clear what factor oil plays in our engines. However, in manipulating the pivot there are additional trends that may be meaningful but as with this view they are still not obvious. If anyone wants the Excel version PM me your email addy and I can forward.

Keep in mind that even among trbology experts there are varying opinions as to whether or not a UOA provides any indication of engine versus simple the condition of the oil. So with that following are the patterns I see.

There appears to be some minimal reduction in Chrome and Copper occurrence in the samples that seems to relate to the use of 10w and 15w40.

There appears to be some minimal reduction in Iron occurrence with the use of 5w20 and 10w30.

And oddly enough there seems to be more significant reduction of the occurrence of Aluminum with the use of 5w20 and 15w40.

These 3 observations are adjusted for mileage on the OCI.

Then when I manipulate the pivot to account for ZDDP I see NO indication that the occurrence of any potential wear metals is impacted by additional quantities of the additive.

Manipulation again for Molybdenum and Boron, both of which serve as antiwear additives I still see no indication that there is benefit to higher quantities of these additives.

One pattern that sticks clearly out from additional manipulation of the pivot is the occurrence of potential wear metals increasing as the engine accumulates mileage beyond 50,000 or so. This is clear, but not still not terribly clear. Maybe this is from bearing and gear wear causing more movement of the rotor? I’m not knowledgeable enough to say.

Another thought I have is that we aren’t interpreting these UOAs correctly. We have a much smaller engine than the piston type possibly meaning the acceptable potential wear numbers should be adjusted down accordingly.

My final thought is that while the variations in metal occurrence between oil grades in minimal the slight advantage to 10w40 and 15w40 may support what some of the engine builders here have said with regard to viscosity and engine wear. To be more comfortable with this logic we’d need some 50wt UOAs and preferably 20w50.

Revs, try the numbers around measured viscosity in the UOA rather than claimed initial viscosity.

Update from Iluvrevs

http://www.flickr.com/photos/9krpmrx8/6685858517/

Coming shortly, stand by.

Sorry man, got super busy yesterday afternoon.

http://www.flickr.com/photos/9krpmrx8/6690178673/

i thought this would be good to include in this discussion:

Metal Tests

Some of the metals tested for and usually included in analysis of an oil sample and their potential sources are:

Aluminum (Al): Thrust washers, bearings and pistons are made of this metal. High readings can be from piston skirt scuffing, excessive ring groove wear, broken thrust washers, etc.

Boron, Magnesium, Calcium, Barium, Phosphorous, and Zinc: These metals are normally from the lubricating oil additive package. They involve detergents, dispersants, extreme-pressure additives, etc.

Chromium (CR): Normally associated with piston rings. High levels can be caused by dirt coming through the air intake or broken rings.

Copper (CU), Tin: These metals are normally from bearings or bushings and valve guides. Oil coolers also can contribute to copper readings along with some oil additives. In a new engine these results will normally be high during break-in, but will decline in a few hundred hours.

Iron (Fe): This can come from many places in the engine such as liners, camshafts, crankshaft, valve train, timing gears, etc.

Lead (Pb): Use of regular gasoline will cause very high test results. Also associated with bearing wear, but fuel source (leaded gasoline) and sampling contamination (use of galvanized containers for sampling) are critical in interpreting this metal.

Silicon (Si): High readings generally indicate dirt or fine sand contamination from a leaking air intake system. This would act as an abrasive, causing excessive wear. Silicon is also used as a anti-foam agent in some oils.
Sodium (Na): High readings of this metal normally are associated with a coolant leak.

Now remember we have twin oil coolers and those big old stationary gears that chew the oil up--lol. We have a huge exposure for the oil in and around the rotors---so a rotary engines percentages will be different than a recips. I am not sure how they compare samples.
Heck its looks like the 30 wgts are doing pretty good.
I have heard from a few of the possibility that the new shaped side seals can't handle the heavier viscositys the 40/50 wgt stuff? no proof offered yet.

2nd Pivot
 

Yay in that it wasn't lost in the mail afterall, boo in that the chromium won't go away. :(

http://dl.dropbox.com/u/25219728/rx8uoa.JPG

FWIW, I have switched to Valvoline 5w30 full synthetic after this oil change (was previously using Valvoline 5w30 conventional).

Ferret, changing from dino to sythetic will not likely make any difference. I think you need to step up the viscosity.

And would somebody explain to me how chromium from the apex seals gets into the oil when the apex seals contain no chromium? And any chromium they scrape off the housings is going right out the exhaust port. The only "action" you could take is rebuild the engine (or better, switch to a higher viscosity!). Methinks Blackstone don't know der Wankel...

I agree, and plan to do that once winter is over with ... or should I just do it now? :dunno:

If you are worried about the cold go with Mobil1 0W-40.

After reading all the goods about it (from you ;) ) I actually ordered 2 cases of the stuff instead of my usual royal purple regimen . Will post some UOA's of my runs with it.

Meh. I run 15W40 year-round now. No trouble starting in bitter cold (and I have original less-powerful starter). I just keep the revs and loads down by driving gently until the temps come up.

Oh, and I have the radiator almost completely blocked once the temps drop below 40. Otherwise I can't get above 175 and more like 160-165 on sub-freezing days. With the rad blocked it goes up to 180-185 and just sits there. Important for keeping viscosity up and moisture out. I don't get any mousse under my filler cap.

I ran some 10W-40 dino oil during break in and I saw no real difference in oil pressure or how the car ran when I switched to my normal 0W-40 last weekend. But, the 0W-40 has performed well for me over the years so I'll stick with it. I'll probably do my first UOA on this engine in 2,000 miles.

I think I will, thanks! Do you use that year-round?

Yes, but it stays warm here year round for the most part.

Gotta hand to the Valvoline for holding viscosity in grade. But, not doing a thing for wear prevention.

I actually did yet another analysis if you guys are interested. M10w40 actually showes as the best choice so far, though it would help to have more samples.

Wankle, how long have you been running 15w40 in the cold? Also, whats your avg cold and max?

I'll have a UOA soon enough and REDRX3RX8 should have a sample coming up I would think as well.