Oil viscosity testing

[quick_16]

Oil viscosity testing

I posted this here for best visibility and feedback...

RP XRP 10W-40
1000hp Methanol injected 565 15:1 drag race engine

I'm pushing the interval this time and was messing around in the shop with a used sample (40 runs). It's pretty clean to the eye and with a drop on a paper towel.

I timed the time it take to drain a turkey baster of used and new oil, just as a simple test to see if it has been diluted or sheared out of grade. I did not measure any difference between the two. 50cc in about 25sec

Sample is on the way to Blackstone to be sure. With TBN

Has anyone ever messed around with this? Was wondering at room temp, if my little test would show a difference in some sheared or diluted oil? I did it at around 70F. Would be hard to do it at 150F normal temp.

Please understand my eng tune up is not like the typical and I do not have fuel in the oil as you may think. I use a 2nd gas fuel system to put heat in the eng so the injected meth is only when racing. Wide Band O2 is .85 lambda so it right!

Looking for feedback based on 1st hand knowledge on this as opposed to guessing thanks.
O and this is just about saving some cash and doing it with test data so it's safe and all.......

 

[JAG]

I've done it with a syringe and it was decent enough to measure large viscosity differences. My problems were getting the same amount of oil in and more so, knowing when to stop the stop-watch. The time between drops got higher and higher near the end and not all of the oil could drain (due to adhesion). So when do I stop? I settled on stopping when the time between drops reached some value. That's not perfect.

Your turkey baster may be better due to its larger size and less adhesion effects (oil to walls).

To have decent trust in only one measurement, your error should be a smaller percentage than the expected percent viscosity difference between virgin and sheared oil. You have to measure your error range by measuring same oil maybe 10 times. Calculate the average and the percent change to the highest and lowest times. Maybe it is 25sec plus or minus 1sec, so that's plus or minus 4%.

Your oil might lose over 10% of its viscosity. If it took 25 seconds with virgin oil, you'd ideally measure 90% of 25 seconds = 22.5 seconds on the sheared oil. The question is whether your measurement error is much smaller than 10%. If so, you can have some confidence in having measured a 10% reduction.

If not, you have to keep re-measuring the same oil plenty of times in virgin and sheared states and take the respective averages. That's the brute force method. That's what I used to do.

 

[quick_16]

JAG, Thanks for the input. Just finished my BMG 6 sigma Green belt certification and failed to think of DOA. lol

I'll retest 10 times each and see what I get. The baster had a 50cc mark that I filled to and when it got to the area it stated to neck down I stooped the count.

What are your thoughts on doing this cold vss HOT. Can I assume it would it repeat HOT like at 70F?

 

[JAG]

That's a good way to stop the count.

If the oil "is sheared", as in broken polymers, or it is fuel diluted it will reduce viscosity at all temperatures. The percentage viscosity loss relative to the virgin oil may not be identical (in actuality) at both 70F and 150F, but that's ok. It probably isn't identical because the polymer viscosity index improvers contribute to the viscosity at varying levels as a function of temperature.

Given typical polymer thickening behavior, I'd say that if you measure X% viscosity loss at 70F, it would be a little higher than X% loss at 150F. But I wouldn't worry about that.

It would be different for fuel dilution due to the mixing rules of fluids (the thinner of the two fluids has greater effect on the mixture's viscosity as the difference between the two fluids' viscosity increases). Basically, I think that fuel has greater "thinning power" in motor oils as the temperature decreases because the oil itself if thickening while fuel viscosity barely thickens at all. But still, I wouldn't worry about that minor effect.

70F is good enough for what you are going for in my opinion.

 

[quick_16]

All it took was 5 of each to see that the used oil is a tad thicker as it took just about 3% longer to drain. What the heck can then mean??

 

[JAG]

One possibility is solid contaminants but you said the oil looks pretty clean so I doubt that.

The other possibility is thickening from oxidation/nitration. Is the oil tortured by enough high temperatures and time to chemically degrade the oil?

You could do a blotter test which may reveal one or both of the above.

 

[quick_16]

should have test results Monday and will post.

 

[quick_16]

SUS @210F 78.0
RP XRP10-40
no idea what Virgin is
Last test 29 runs = 75.9
Test with 27 runs 71.2

So my home test was correct and the oil was thicker.
more results

Fuel % = Antifreeze % 0.0
Water % 0.0
Insolubles % 0.5%
TBN 10.2

Lead was high because of this q-16 race gas I use as a primer and no load idle fuel

 

[JAG]

0.5% insolubles is rather high. That will thicken it up. Do you know what the source of insolubles is? Foreign matter or oxidation/nitration?

 

[afoulk]

If its a drag race engine, my guess is hes not running an air filter, maybe thats where the insolubles came from.

 

[quick_16]

Yes I do run and air filter look at the Silicon in the link to the test. I have done many UOA and that level of Insol is typical. In fact just looking at my street car test data .2 to .5 is typical on those as well. Maybe it the fla air lol???

I also run less of a oil filter. It's a System 1 pleated mesh type with 30 micron element so I don't have a great deal there

https://bobistheoilguy.com/forums/threads/royal-purple-xrp10w-40.100811/