No, there are other labs. There is one in Montreal, but it's super inconvenient for me to get to during working hours. Easier to drop things in the mail. I imagine Alberta and BC would have a whole bunch given the amount of heavy machinery deployed there.

 

Second take, this time with 2 AutoX sessions on the oil.

Wear looks fine, but the viscosity additive seems to be wearing out a bit. IIRC this is an issue with conventional oil. Maybe I should change the oil a bit sooner with AutoX events, 2500 miles/4000 km vs 3000 miles/5000 km. Any tips?


Same oil as always, Pennzoil 5W-20 conventional in yellow bottles.

 

^ Eh. You kind of need to tell us what kind of oil it is for this to be meaningful.

 

Oh sorry, it's 5W-20 Pennzoil conventional oil. Comes in these yellow bottles.

 

I had some Castrol GTX 5W20 samples several pages back in this thread for comparison, but the pictures have disappeared for some reason. I'll try to remember to re-post tonight. I had track days on my oil, and it came back within spec. Even so, I started using Mobil 1 0W40--at least in the summer.

I feel like I should have mine tested again, but it will have to wait, as I currently have dealership mystery oil mixed ~50/50 with the aforementioned Mobil 1, plus an unknown quantity of Valvoline Synpower 5W30 top-off oil. That witch's brew is probably not worth testing. It does show my commitment to the idea that what kind of oil does not much matter, but the frequency of change does. I'm still changing the oil at 3,000 miles and changing the filter at 6,000 miles.

 

I see nothing wrong with oil or engine. The lab seems to think it's straight sae 20, and it does seem thicker than any multi grade 5w20.

 

Thanks a lot Steve!

I do change the filter with the oil every change. They are only $10 a pop at the dealer. Maybe I should do it every other change as well, but I thought 6000 miles might be a wee bit too long. Even with the Owner's Manual's overly long interval, they say the oil should be changed with the filter every 5000 miles.

It's interesting to see the results because I have seen that couple of years back, people were bashing on 5W-20 a lot, saying it's too thin. That said, if I live in the Texas/Cali summer, I will probably use 5W-30 as well.

Also, your dealer is okay with filling up synthetic and 5W-30? Lots of dealers aren't. Last time I checked with my dealer, they still stand by 'no synthetic', even though people are fine using it.

Wear and additives are completely fine.

I looked up the specs for the Pennzoil 5W-20 conventional and it seems that the oil has indeed got thicker than it's supposed to be at 40 C. Could just be the viscosity control additive wearing out.

 

But oil gets thinner as it ages. The additives are long chains that give it viscosity, and they get chewed up by oxidation and heat stress. I would question what oil was actually in there. Perhaps your previous fill was a heavier oil and a bunch of it remained during the last change?

 

I do my own oil changes and I have always poured in 5W-20.

 

I may have left out an important detail or three...

My oil change regimen is as follows: I take it to the dealer every 6000 miles for an oil and filter change. They use who-knows-what bulk oil, although they claim it is Castrol GTX 5W20 in the winter or 5W30 in the summer.. From there, I will drive the car 3,000 miles OR take it to the track 1 time. Then, I drain and fill with Mobil 1 0W40. So, at any given time, my car has roughly 2.5W30 semi-synthetic in the sump, since we are able to drain ~half the oil.

I take it to the dealer for 2 reasons: 1. Maintain the paper trail, as my engine is still under warranty; and 2. I can't beat their $20 or $25 price with coupon by doing it myself with an OE filter and any given oil. When I do my own drain and fill, I go to MyMazda.com to enter a service record to document it. Either way, I am technically within Mazda's recommended interval of 7,500 miles, so warranty work should not be a problem if needed.

As for how I ended up with the witch's brew I have in there now, consider 1 dealer change, 1 of my changes, and make-up oil from what I have on hand for my truck. BTW, Valvoline Synpower must be pretty good stuff. It is all I have ever used in my 2008 Tacoma, and the truck just turned over 235,000 miles with plenty of towing and other hard use, and the engine is still purring along like new.

Here is that Castrol GTX 5W20 report with a track day on it, but only 1,000 miles. This is back when I was using Castrol GTX 5W20 myself, and the dealer claimed to be using the same. At that time, I did a drain and fill with Castrol GTX 5W20 after every track day.

 

Right, your warranty is based on the Schedule 1(non-severe), while we Canadians follow Schedule 2(severe). I don't have a warranty anymore anyway.

My dealer said they use Shell oil. Not that it matters since I have done oil changes myself since I purchased the car.

 

These kind of multigrades start with very thin like 5 Sae and put vi improvers which are like saggy long springs to keep from thinning when hot. They can get chewed up which would take oil thinner. Only way to get thicker is oxidation of oil, too long used or hot.

Your conventional really specs at Sae 20 straight weight which is what analizer said.

What is that additive control measure?

 

I'd be curious to see how a broken-in engine UOA compares with 0w20 synth and 0w40 synth (with 2 stroke for oil injection via SOHN). I may send some samples off after I get 10,000mi on my new motor. I'm still trying to decide which I'll run, though I'm leaning toward 0w40 to start.

There is a lot of old information out there on oils that may not be relevant anymore and it is hard to separate it from what is current and trusted knowledge from the industry. 0w20 worked brilliantly on my Sky-G car (Miata), and I run 5w30 on my other vehicles without any fuss (including an LS* V8). Seems Mazda's Idemitsu-derived 0w20 synth (with moly) has tested well in UOA on high-compression/DI piston engines, as has their bulk dealer oil, Castrol GTX Professional 0w20 synth (with moly). I've used both and noticed no difference between them, both seemed to manage 5k miles of hard driving without a fuss.

 

Question:

Is there any existing spreadsheet with any decent number of UOAs from this thread? (The last reference in this thread is from 2012)

I'm working on a central repository for them, hosted on google docs and accessible via my website or direct link. I already have a form set up to attempt make data entry a bit faster, as well as simple and accessible for people looking to add their own. Just wanted to check to see if there is anything i could import in before i start the manual slog.


...or if anyone wants to help take on a chunk of the work to help me out

 

Hi RIWWP, good to see you here.

I think there would be a lot of data to include other than the wear number, such as the driving style and location(and thus, the climate).

I personally don't see a point to use anything thicker than 5W-20 in my area, but if I track in Texas, I am definitely going up in viscosity.

 

I only agree to an extent. Generally, the climate will influence the cold wear, but not the hot wear, as the hot conditions are thermostatically controlled. I could in theory use the location information from each post to retroactively 'report' on that, but it isn't reliable and adds a layer of tedium

Driving style, namely track vs not, average trip length, could definitely make an impact, as they give an indication of the ratio of high RPM vs low RPM and ratio of cold wear to hot wear respectively. But they haven't been reported for most of what I skimmed through, so it would be hard to get them added. :/

From a simplicity perspective, I think that just reporting on the straight factual numbers rather than subjectives would produce the cleanest data to really use.

 

Cool, I will upload the two data sheets I have here to RX8Help then.

BTW, what do you mean makeup oil? Just the amount of engine oil added in between intervals?

 

It's the line from the Blackstone Labs report, and my understanding is just what you assume, it's the amount of oil used to top-off between changes.

 

GTX 20w50 SN. Pretty happy with this oil in this engine. Some weird stuff though. This is Smutterbutter's home rebuild at 17k miles. (purchased from him 6/2018) No track use, but decent amount of redline work, in Arizona heat. Two prior oil changes with this same oil. This oil was run in ambient temps over 115F. Sohn with Maxima super M injector and running that as premix also. OMP modded to inject more oil. (change to 2 large pumps, instead of one large one small). The "additives" they mention I added is the 2 stroke oil. ZDDP was amazingly low, but overall I was pretty happy with this result, and the lack of wear metals. They mentioned that additives may be diluted and wear metals also, but the moly content is about the same as some other UOA I can find for this oil, the and the viscosity is the same also. The 10w at 100c 2 stroke oil would definitely thin it out more if that what was causing the missing additives. But TBN was good. Some additives are "missing" though, in an inconsistent ratio. Where did they go? My aim was to run this oil and change frequently since it was cheap, and I was worried about fuel dilution. It seems to be better than I hoped. Interestingly, there is another test of this SN oil recently on BITOG that was strangely excellent also, in a 300zx. Hmmm. Its in the oil pan again, so I will get another test and see how it does. Comments welcome.

 

Looks like very low wear, and the low ZDDP might be a feature of the SN oil to go easy on cats.

I don't see how a significant amount of OMP or PREMIX can get into sump oil on a rotary.

There's not even much dirt (silicone) in oil since over 12 is high number, and some oils come with 7 from silicone as anti foam.

 

I like how they're impressed you didn't have to add oil
But looks good! It was about due.

 

Yeah but that zddp is super low, even for SN. I can't really find many other UOA or VOA on this oil for comparison, because WalMart shoppers like me who buy 20w50 don't usually spring for oil analysis on $3/ quart oil! Maybe others will join the cheap 20w50 club and add to the data.Maybe.

 

What oil did you run before this? Because the zinc in ZDDP is deposited as a protective film on metal surfaces, so you expect to find less of it in used oil than in virgin. Eventually you reach equilibrium where it's deposited at the same rate as it's consumed, but I have a feeling it takes a long time to get to that point, perhaps even never for a single oil change.

 

Good point. But, I have done 2 other oil changes at a shorter interval as a flush. So about 3K miles previous to this change running this oil, about 6k total. Before that, I believe the PO used Idemitsu 10/30. But maybe that's not enough time to build the ZDDP equilibrium in this relatively fresh engine with the Castrol.

 

This sample had a few cold starts (just less than 30 degrees F) which was no problem, and the pressure on the mechanical gauge built quickly. The fuel dilution was from the colder weather here I think. I did run the car harder in this sample, but was still street driving, no track stuff, so it wasn't really that hard. I am still surprised at how low the zinc and phosphorus is though. It is a SN oil, but that is strangely low, I think. Both samples shown here are GTX 20w50 SN.