A review of polymer dissolution

[JAG]

I'm posting this because it applies to how cleaners in motor oil may clean varnish and other hard deposits. Varnish consists of polymerized material. One thing it answers that I suspected is that solvent molecule size affects the ability to dissolve a polymer. That is why a very low viscosity solvent can dissolve things so much better than a base oil of with similar polarity but with much higher viscosity and molecular mass. The large molecule size limits the oil's ability to diffuse into the material. Smaller is better at penetrating into the polymer. The paper describes the layers that form in a polymer when exposed to a solvent. A gel layer forms next to the solvent. I found it interesting that the paper discusses how cracks can form in the polymer from internal pressure due to solvent diffusion into it. We've seen chunks break lose from deposits which I bet are a result of cracks first forming.
http://www.eng.buffalo.edu/Courses/ce435/Koenig03.pdf

Here is another good paper: http://doc.utwente.nl/70803/1/Koenhen75determination.pdf

 

[Farmsteader]

so Jag , which Engine cleaners are on the ,"Go to list" ,? I need to clean a 190k Caravan 3.0 six banger, that we gotta get in better shape, our bad, we use it as a Farm Truck, and now want the engine cleaner and running tip top, it has good power, but we know it could use a good cleaner to loosen the gunk build up,and ready to add some MMO and LM2009 Mos2. Thanks for this info .

 

[JAG]

I'm going to try to find that out myself through trial and error. It's a tricky matter since the chemicals that clean the best have very low viscosities and high evaporation rates. Also, clogging the pickup screen is always a concern. Lastly, partially dissolving plastics and elastomers must also be considered. I recently took off a heavily varnished oil pan so I plan to put see how well different solvents clean it. I did a really quick test so far which consisted of putting the following on Q-tips and rubbing the deposits 10 times with equal pressure: isopropyl alcohol (70%), brake cleaner, and acetone. Also rubbed with a Q-tip that had no solvent on it. The first one cleaned a bit less than the last two solvents. No solvent cleaned a little less than isopropyl alcohol.

I'm going to try to find a way to re-test that does away with rubbing and may segment the oil pan with plumbers putty or gum so the solvents can soak there and not mix. I also want to try products that are designed to clean engines like the older solvent type Amsoil engine flush that I have, Seafoam, and whatever else I can find at stores here.

The instructions given for engine flushes seem to be geared toward preventing engine damage and making them more convenient at the expense of their effectiveness. For example, it would certainly be more effective to do what they say then turn engine off and let it sit for at least a day and then repeat since that wait time will allow the solvents to diffuse into the deposits and weaken them. Another trick is to not idle the engine like they say but hold RPMs at 2000 or 2500 RPMs to increase flow rate and therefore agitation. Another option is to use less solvent concentration and a use in a thicker oil than normal, and drive the car around normally for however long. I'm doing that now.

You could try Seafoam or MMO. I've heard of people having them clean well. If you can find it, you could try Lubeguard's flush since it has had positive feedback. Don't clog your oil pickup screen and not catch it in time! I'd feel partly responsible if you did and I didn't warn you of it.

 

[Shannow]

Basestocks can do OK at cleaning varnished surfaces, provided that the varnish can be stripped out of the oil. The "clean" oil, will then try to reach a new equilibrium with the varnish, and if that can be stripped out, eventually all of the varnish can be removed, without the addition of solvents, which work one time until saturated.

I sponsored an undergrad thesis last year on varnish, in low additised Gr1 and 2 basestocks, and it's really a fascinating field. Typically, the varnish is formed in one place, and deposited where the solubility is lower. It can be a high temperature place, an arcing filter (some media generate enough static to break oil down), an aerated place...and drop out on a bearing housing surface that is cool.



We are looking at using electrostatic means to remove varnish from solution, which will strip all of it out of a system.

By removing it, equilibrium will mean that even some of the cold "set" stuff with mobilise...in a car engine, 20 Oil Fills worth of varnish deposit won't be shifted in 1 OCI/application.

Been wracking my head to see if a scalable solution is available, but also wonder if there's not a way of creating a "cold" spot for the circulating varnish to settle out on that can be changed out/cleaned during an OCI.

My first car had rocker and tappet covers literally filled woth sludge (rockers had their own grooves in the sludge), after 7 years of no servicing, and top-ups with 20W-50 Castrol.

I scraped the rocker cover out, the side plate tappet covers. Then drained the oil, and added a couple litres of diesel. Idled for 10-15 mins from cold, and it drained out like gear oil.

20W-40 recycled oil, and burned nearly 2 litres in a week...repeat a few times...engine running better, and finally changed to Valvoline XLD, and it stopped massive consumption, and ran great while I had it.

In hindsight, I think that weekly oil changes, albeit with cheap oil, probably did more than the diesel...but I did get into the habit of idling with a quart of diesel in that engine before each OCI Justin Case.

 

[JAG]

Very interesting. Thanks Shannow. In the first video is varnish dissolving due to the oil heating up?

 

[Shannow]

Yep