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Soot -V-Viscocity

S signss24Member
I am rather confused on results I am recieving from my lab reagarding Soot-v-Visc it is not adding up at all. Currently using Penzoil Long Life 15w 40 in DD Series 50 EGR engines, and Quaker State 40W HDX In 6V92 .1 engines. All additives etc look normal but when I see a 5.2 soot level in one result with a 15.5 visc and then a 3.8 soot with a 21.+ visc im stummped. I do know the oil is good at suspending the soot but it appears to me it works well one day and not the next. What am I missing in the test results? I have taken into consideration Idle time, weather, Low Sulphur Fuel, etc etc etc and cannot figure this one out.
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B balaMember
1# Soot Increases Viscosity,Depleates Dispersant
additives,Causes abrasive wear.

2# Oxidation also Increases Viscosity,Depleates
additves eventualy throws Sludge.Get FTIR Spectrum,Observe for oxi peak at 1700 to 1730 cm-1.Elevated Oxi in an indicative of oil is
getting burnt.

3# Soot correlates with Iron wear.High soot with
less iron is in indicative of the performance of
dispersant additives.

4# Elevated soot is combustion related problem.
Defective injectors,Excess Blowby,Seized Turbo
causes poor combustion.Observe the soot trend,
Get it fixed.

Hope this helps.

Bala.
S signss24Member
Thanks Bala,
I wish it helped, I know as soot rises visc does also and I do know it causes wear and iron increase. But as I said there are days the soot is high and the visc is high also and then there are days the soot is high and visc is normal. I do believe Im not getting good results from my lab. We have a very strict turnaround time for results and Im thinking there is poor QC resulting in my on and off readings or coralation between soot and visc.

But I do thank you for your input
P prabhakaragrawalMember
Signss,
Soot increases the viscosity, but fuel dilution decreases it, the combined effect of both on viscosity may be nil. The result will be, even if the soot is very high you will get normal viscosit.While independently the soot may be beyond allowable limit and the fuel may be also beyond tolerable limt. So please check the Flash point also to know the fuel content in oil.
Sometimes Lab technicians don't test the sample religiously and give results in a relaxed mood, that may be another reason, so you may send your samples to two different labs for counterchecking the results.
K kumarMember
quote:
Originally posted by signss24:
Thanks Bala,
I wish it helped, I know as soot rises visc does also and I do know it causes wear and iron increase. But as I said there are days the soot is high and the visc is high also and then there are days the soot is high and visc is normal. I do believe Im not getting good results from my lab. We have a very strict turnaround time for results and Im thinking there is poor QC resulting in my on and off readings or coralation between soot and visc.

But I do thank you for your input


Your concern withregard to high soot high viscosity and high soot normal viscosity, it is all based on oil top up. Dispersant additive component in the oil plays an important role in controlling viscosity not to incresae inspite of soot incresae. May be the oil shows less viscosity is imparted with better dispersant than the high viscosity oil. This requires lot of discussion with oil suppliers

Kumar e mail kumartr2@yahoo.com
S stefanminnaarMember
Soot and viscosity do have a correlation between them but as stated by the previous respondents there are several factors that can make the relationship between soot and viscosity less linear.

Something we have noticed is that you might get increase in soot and viscosity BUT the flip side of the coin is also possible. The root cause of the sooting problem must be considered.
  • Blocked air filters will definitely increase your soot level and if left unattended for long enough will result in fuel dilution - hence high soot low visc.
  • Additive package could appear normal if sweentened by regular top-ups e. g. the engine could have high blowby (acidity will also increase) and this will eventually lead to soot and increased viscosity.
  • You mentioned EGR, we do not have many of those engines running on our site but it makes sense that you will have to pay MUCH more attention to your air filters etc to prevent excessive generation of carbon (black smoke) which will in turn act as a coaggulant .... and the vicious cycle repeats itself.

    Are the units operating in a particularly dusty environment / climatic extremes...?

    In short, try to get to the root cause, check your engine air induction system properly for any restrictions and the blowby as well depending on the age of the unit.
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