Piston Soak for reducing oil consumption

[Emanuel]

Originally Posted By: Ducked
In Venezuela you could probably run a straight weight oil which MIGHT cut consumption a bit and would reduce the chance of ring sticking, IF that is likely to be an issue.


I'm gonna do one last oil change with the HDEO 15w40 because I already bought the oil and then I a going to use 20w50 again, the coldest starting temp the engine sees is 68 °F and the user manual says that you can use 20w50.

 

[Emanuel]

Originally Posted By: Ducked
Stuck rings doesn't sound especially likely in this case.
Couldn't the overheat have caused that the rings got stuck? Or they need more miles to be considered stuck?

This engine is known for oil consumption, specially the higher mileage ones so I might just end up using the thicker oil that the manual recommends (20w50) and accept that is just the way it is.

 

[StevieC]

Look at the carbon reduction around 11:30 onward.

Then see how he does it. Maybe sucking up some water into your intake can help de-carbon the rings.

 

[Ducked]

Originally Posted By: Emanuel
Originally Posted By: Ducked
Stuck rings doesn't sound especially likely in this case.
Couldn't the overheat have caused that the rings got stuck? Or they need more miles to be considered stuck?



They need to be stuck to be considered stuck. That usually means gummed up. I don't think heat or mileage alone would do it. Rings can seize in the bores but AFAIK they don't seize to the pistons because there isn't enough relative movement (experts confirm?)

My reasons for suggesting straight weight oil (SAE 40 or 50) was that it should be suitable for your conditions, it'll probably have a higher average effective viscosity both because it starts thick and won't shear in service (both of which should reduce your consumption a bit), and it wont gum the rings up with degraded viscosity improvers, which is known to happen with some engine/oil combinations.

 

[Ducked]

Originally Posted By: StevieC


Look at the carbon reduction around 11:30 onward.

Then see how he does it. Maybe sucking up some water into your intake can help de-carbon the rings.


There's not actually a Seafoam comparison here (you'd need a few engines for that), though I wouldn't find it hard to believe that water was as good or better.

Re "Water is free and available anywhere in the world" I'd say you don't want to be using tap water for this, unless you're somewhere with especially soft water, like, say, Scotland.

Bad timing for my decoke, since the not-summer is starting in Taiwan and the supply of aircon condensate is drying up.

Re how he does it, I wouldn't do it that way.

 

[StevieC]

It's in other videos on his channel.

 

[Emanuel]

Originally Posted By: Ducked
My reasons for suggesting straight weight oil (SAE 40 or 50) was that it should be suitable for your conditions, it'll probably have a higher average effective viscosity both because it starts thick and won't shear in service


I dont know if a SAE50 would really have a higher average viscosity, maybe it does... But AFAIK a 20w50 has a higher kinematic viscosity at 100°C than a straight 50 oil.

I don't like how thick SAE50 oils are when they are cold, I think that they could cause wear specially when the engine is cold, that could increase more the oil consumption.

And finally the problem is that the SAE50 oils avaible here have very obsolete ratings, I think they are API CF rated. In 3-4 months I will test 20w50 again and see the results.

 

[Ducked]

Originally Posted By: Emanuel
Originally Posted By: Ducked
My reasons for suggesting straight weight oil (SAE 40 or 50) was that it should be suitable for your conditions, it'll probably have a higher average effective viscosity both because it starts thick and won't shear in service


I dont know if a SAE50 would really have a higher average viscosity, maybe it does... But AFAIK a 20w50 has a higher kinematic viscosity at 100°C than a straight 50 oil.



I believe the API grade is based on kinematic viscosity measurement. If that's the case, there shouldn't be any systematic difference in fresh oils of the same grade measured at 100C.

 

[SilverFusion2010]

They may be the same viscosity but a monograde is inherently stronger. VII do not lubricate and get sheared quickly in some applications