Moly is very corrosion and can fall out if not formulated right. Maybe thats the residue.

Also, he says maybe there's polishing compound in the oil which tells me he's not up to speed on oil.

Oil has detergents that keep ash and dirt suspended until filtered or drained.

I'll throw my wild theory out there that some of the iron in these reports isn't wear, but cleaned up rust off housing.

No need for polishing residue, and that stuff he burned would be in the combustion area , not the oil sump.

 

That is a good point about the iron coming from the irons.

 

so you guys are sayin diesel oil will run better then a synthetic gas oil?

 

Welcome to the forums.

Read the test results and come to your own conclusions. My own conclusion from my testing, rx8convert22's, and others is that the 15W40 (Rotella T specifically) is the only oil that retains viscosity over the life of the oil in track-driven RX-8s. The others I've tried show less than the minimum acceptable viscosity at the end of their life.

Synthetic doesn't appear to offer any benefits over dino 15W40, and costs much, much more. No benefit, higher cost, why bother?

Then again, it probably doesn't matter at all what oil you use since the primary failure mode for the RENESIS seems to be loss of compression from side seal and sometimes apex seal failure. I dont' think I've seen a single RENESIS die purely from a lubrication failure (as opposed to hose, cooler, or pump failure). Use the cheapest crap available at Wally World and you'll likely get just as much engine life. See the "Oil is Oil" links in my sig.

 

thanks alot i appreciate the insight

 

Mobil 1 0W40 is like $25 a gallon though.

edit: welp nvm, didn't know the Shell 15W40 was $13 a gal

 

Typically M1 costs about $12.00 more than conventional oil. My car is not a daily so I don't sweat the extra $12.00 expense every few months. But the cost consideration is a personal decision.

 

Yeah but the M1 0w40 has held viscosity the best of any oil since the SN update so the 12 is money well spent. Pretty much isn't shearing anymore versus everything else.

 

Good point.

 

First UOA after just over 900 miles on reman engine core.

 

Chrome seems high, likely housing where reused.

Get a Sohn, and stop using 5W20!

 

Yeah man imagine over 3,000 miles. Get some 10W-30 in at least. But really a good 5W-40 or even better 0W-40. Thanks for sharing.

 

I put in 5w-30 this time. I'd like to put a SOHN in but my warranty is still good thru 8/2015 so I don't want any hassles with service at Mazda in case something comes up.

 

I was actually wondering about this. I will be going home to egypt for a while and will probably be buying a car for there andb it will be an rx-8. The issue is the only way to get maintenace done there is at mazda because there are zero specialists anywhere in egypt. Ive been reading up and its been said that in seriously hot weather year long its Bette to use at least 10w40 or even 20w 50 in a country as hot and dry like egypt. And it does get a little cool in the winter season (5° c at night and 15-20 or so day time)...in which case I guess 10w40 would be the optimal choice. What else should I do ? In know over here in canada they have gas cleaner so if I find some there at the game stations I guess itd be a good idea on a 10 year old car

 

First of all the statement that oil is oil is a lie. Mazda recommends synthetic 0w30 for the RX8. 0w30 gets better fuel economy, lower emissions, reduced wear and longer engine life compared with a petroleum 5w20. 0w30 also reduces deposits on the apex seals.

Now if oil is oil try and find a petroleum oil that meets the 0w30 specification. Such an oil does not exist because it is impossible to formulate a 0w30 oil that meets warranty requirements without being at least a synthetic blend.

 

Hello androbot, welcome to the forums.

Please read a thread and related links thoroughly before flying in like a seagull and crapping all over everything. Do your homework.

Mazda does not recommend 0W-30 oil. If you read your owner's manual you would know that. in fact it even says what oil to use right on the filler cap! Bet you didn't read that either, did you?

In fact Mazda recommends against synthetic in all rotary engines. From the 2009 RX-8 Owner's Manual: "Do not use either synthetic or semi-synthetic motor oil. Otherwise engine starting performance could worsen." So you have that warranty nonsense completely backwards too. Synthetic may void your warranty.

If you had read the relevant posts about the fact that oil is oil like the ones linked in my signature you would have read this:

If you're a troll, as many of your posts appear to be, I applaud your work. I took the bait.

 

Wankelbolt, They recommend different oils in different places.

 

While you are not completely wrong, you are also not completely right. Deposits don't form on the Apex seals, ever. But I agree a full PAO 0W is good stuff. But GC 0W-30 did not perform all that great in my 8 during a short 1500 mile OIC, so yes not all oils are the same. I have several test results here you can look at.

 

Had an overheat about a month ago, starts and runs great. Thoughts?

 

Iron and magnesium are really high. I would expect some internal damage.

 

Yeah way out of whack. No coolant in the oil but you could have warped hard parts.

 

Time to boost it till it pops! I wish my engine was on its last legs, I would destroy it and probably enjoy my car more in those couple hundred miles than all the thousands I have already.

 

UOA from Grungepups car (07' with 30k on a Mazda reman). Notice the high Boron, it is used to harden metal.

 

Anybody use Idemitsu? I use 10-50 and it seems to be pretty good. But it goes black kind of quick. About 1500 miles in it looks about as used as my old civic after 3000 miles. Does anyone else have any positive stories on Idemitsu oil?

 

There is really no reason to mess with running Idemitsu but I am sure there are people who do run it. I would like to see it tested. FYI, the look of oil has no bearing on how it is performing.