Jump to content

Shell Rotella at 2.4 hrs

By aj_yz426,
in YZ400F/426F/450F/450FX

 Share

Recommended Posts

Contributor

aj_yz426

Posted
Posted

More FYI for anyone interested, but I also have questions at the bottom if anyone can help interpret this.

Shell Rotella 15W40 oil tested at 2.4 hours on the hour meter (report says 2 but I guess they didn't care about 10ths of hours when I wrote down 2.4).

2001 yz426, after riding in very sandy conditions, basically a big sand dune with lots of hill climbs and single track around an old ski hill(Black lake ORV scramble area in Michigan). Very dry dusty and fine sand that day.

rotella.jpg

Here are my questions:

1) The report says copper could come from bearing wear or the combination of silicon, copper and lead could be in dirt that is getting past the air filter. I also had a fresh clean and oiled uni foam air filter. I never have run race gas or supplements with lead. I still use hiflofiltro brass screen oil filters since I got a bunch with the bike when I bought it (I know they are not good and I'm ordering a Scott's now). Could the brass mesh filters contribute to the copper,lead or silicon in any way?

2) Lead seems pretty high. I never used race gas, but the guy I bought it from told me he had used a 50/50 mix of race/pump gas, could that leave traces of lead this far out? Its had many tanks of pump gas through it over the last 6 months I've had it, but I guess its never been fully drained dry.

3) Is sand/dirt the only cause of high silicon?

4) The viscosity at 100C is 12.3, I believe 40 wt oil should be at least 12.5 so its just out of grade at 2.4 hours, right? This supports a 2 hour change interval if I continue to use this oil.

Thanks

  • Like 1
Link to comment
Share on other sites
Grand Master

grayracer513

Posted
Posted

1&2) The metals aren't really elevated that much. There aren't any bearings in the YZ that I can think of readily that have any copper in them, but there is the clutch, and many aluminum alloys contain both copper & silicon, along with other metals. Frankly, I'm surprised there isn't more iron with the transmission involved. I don't see much there to be real worried over. If you forced any old carbon into the oil, it could have carried deposited lead with it.

3)No. Like I said, where there is elevated copper and aluminum, you'd expect a little silicon to go with it.

4) There's a little disagreement about exactly where 40 ends, and 30 starts, but whether it's 12.1 or 12.5, it's close to the bottom of the range. Unless I am mistaken, Blackstone uses SUS viscosity testing, then does a conversion of the SUS numbers to yield centistokes (my apologies if this is incorrect). The trouble with that is that SUS testing is a wee bit fuzzier than true cSt testing, but the equipment is much easier to afford and use. It would be interesting to know what the oil started out at.

  • Helpful 1
Link to comment
Share on other sites
Grand Master

SUnruh

Posted
Posted

i have been doing oil analysis via blackstoned for 8.5 years now and over 60 tests.

1) take a big magic marker and cover the text with it. they dont have a clue.

2) the aluminum is just about normal for 2.4 hrs in the sand. usually it is from the clutch assembly (the entire basket, plates, pressure......)

3) iron is a hair high, but nothing to worry about. problably from the hard use in the sand.

4) copper is fairly high. usually it is from the sleeve inside the basket that the power shaft goes through.

5) silver of 5 is a wacko reading. i've had a 5 once as well.

6) a silicon of 26 means you need to be running a pre-filter and i use "filter filters" and they rock! oh, and clean the inside of the carb lid.

7) lead is from the former race gas. dont worry

8) the susvis is right in line with what i would expect from a day in the sand. a hair under 40wt. believe me when i said it held up better than most would have dreamed of.

9) the low flash of 370 is from the fuel. did you idle back to your truck or wash the bike and start it and let it idle for a while before taking the sample?

10) if you ever see titanium go above a 2, the valves are toast.

all in all your report is pretty typical of a hard ride in the sand & dust.

  • Helpful 1
Link to comment
Share on other sites
Contributor

aj_yz426

Posted
  • Author
Posted

Thanks for the input. Its reassuring I'm not about to lose my engine.

1&2)It would be interesting to know what the oil started out at.

someday if I feel like throwing some extra money at it I probably will try a before and after.

9) the low flash of 370 is from the fuel. did you idle back to your truck or wash the bike and start it and let it idle for a while before taking the sample?

I had intended to take the sample right after the ride while oil was hot, but forgot all the stuff to do that, so I took it after warming up the engine when back home (just to get the oil into the frame so I could suck it out from the tank). That introduced more fuel into the oil.

Link to comment
Share on other sites
Grand Master

grayracer513

Posted
Posted
I had intended to take the sample right after the ride while oil was hot, but forgot all the stuff to do that, so I took it after warming up the engine when back home (just to get the oil into the frame so I could suck it out from the tank). That introduced more fuel into the oil.
Yes, that is a mistake. I'm surprised the fuel isn't higher, in fact. You must have warmed it up fairly well. Next time, if it's a choice between taking a hot sample, and taking one after running the engine any less than 20 minutes, take the sample cold.
  • Like 1
Link to comment
Share on other sites
Grand Master

reconranger

Posted
Posted

Many fall into the trap of using a UOA (used oil analysis) to evaluate an oil, but used properly they are intended to tell you things about your engine's current condition. In your case, you are getting significant fuel dilution of your oil, probably from compression blow-by! The 426 was an early thumper design so it tolerates a lot of blow-by, plus your one single compression ring (!) is probably shot to hell!

To be 40 weight, an oil viscosity must have a cSt @ 100 degrees C of 12.5 to 16.3. Rotella 15W40 begins life with a cSt of 15.5, and you are down to 12.1 after only just 2.4 hours...that's terrible!!!

The viscosity range for 30 weight is 9.3 to 12.5 cSt @ 100 degrees C, so at 12.1 you are ending up with a 30 weight oil, which isn't a disaster but probably not the hot ticket for racing on a hot day, and if you raced another hour or two....things could get exciting!

See tech data sheet for 15W40: http://www.shell.com/home/Framework?siteId=rotella-en&FC2=/rotella-en/html/iwgen/what_drive/zzz_lhn.html&FC3=/rotella-en/html/iwgen/what_drive/what_drive_dpu.html

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

ThumperTalk

Register a new account Sign In Now
 Share
Go to topic listing
×
×
  • Create New...
Terms of Use
Copyright
Privacy Policy