Oils that can control ring deposits

[friendly_jacek]

I've done a lot of reading on ring deposits and oil consumption lately. Good cases in point are Saturns and pre-2003 Corolla where there were insufficient oil drain holes in pistons. Not sure why it was overlooked by designers though. Shooting to higher fuel efficiency?

Now, one would think that quality oils like Mobil 1 would prevent those deposits from happening in the first place. Thus, I was surprised to find from various blogs about Saturns users who used Mobil 1 from the start, but would still develop severe oil consumption by 80-90000 miles. Also, a Toyota mechanic from UK mentioned that he saw gummed up rings in Corollas with both regular and synthetic oils.

To me it looks like the piston temps in some engines are high enough to carbonize any type of oil if there is not enough flow (lack or insufficient oil holes).

On the other hand, we know that some oils (delo or high mileage) are credited with decreasing consumption in oil burners. Why would that be? Cleaning action from high detergent oils?

Finally, my question. What oil would you recommend to prevent gumming of rings in engines with insufficient oil holes. Would they be the same ones that decrease oil burning in burners?

Thanks!

 

[Audi Junkie]

Look at the Lubrizol Euro oil spec comparator. iirc, VW 504/507 oils excel at this, Mobil 1 5w30 ESP Formula.

 

[d00df00d]

I've heard RLI oils do well in this department, too.

 

[addyguy]

I'd guess Ester-based syn oils would leave the least ring deposits of all syns. Esters handle heat the best of all base oils, hence their use in jet engines.

 

[tig1]

I have used M1 oils for 31 years with 10,000 mile OCIs as well I know at least 50 people using M1 for many years on very high mileage engines and never heard of this problem with M1. In fact M1 oils are known for controlling high temp deposits for turbos. The ring area of an engine is very hot so the deposite benifit of M1 oil would be apparent. My only guess as to the deposit problem on Saturns would be OCIs well in excess of say 15,000 miles. Never heard of it other wise.

 

[SLCraig]

Originally Posted By: tig1
I have used M1 oils for 31 years with 10,000 mile OCIs as well I know at least 50 people using M1 for many years on very high mileage engines and never heard of this problem with M1. In fact M1 oils are known for controlling high temp deposits for turbos. The ring area of an engine is very hot so the deposite benifit of M1 oil would be apparent. My only guess as to the deposit problem on Saturns would be OCIs well in excess of say 15,000 miles. Never heard of it other wise.


It's the older S-series. You see, most people could not go 15k miles on an OCI because the crank case would be bone dry by then. I believe it's from doing a full 5k OCI without once checking your oil, and when the car goes in for an oil change, only a quart comes out of the sump. In that case the oil must get really worked and sludges up the engine. On my 96, inside the valve cover is pretty sludgy. Luckily my car still runs good but I think it's had its fair share of questionable oil changing in the past.

 

[friendly_jacek]

Originally Posted By: tig1
My only guess as to the deposit problem on Saturns would be OCIs well in excess of say 15,000 miles. Never heard of it other wise.


People reported doing 5k miles OCI prior to developing the oil consumption. So, there was no issue with extended drains nor letting the oil go low.

 

[friendly_jacek]

Something just occurred to me.

Gr IV oils are thermally more stable than lets say Gr II dino, but don't have enough solvency to keep the additives in solution. Thus, Gr IV based oil is really a synthetic blend with say 80% Gr IV and say 20% Gr I carrier (diluent) oil with the additive pack. The Gr I and/or additives maybe the source of deposits. BTW, do we still believe that sheared VII would produce deposits like we used to believe before?

GR V has better solubility to carry the additive pack, so no need for Gr I in the mix, right?

Not sure about Gr III.

 

[GMFan]

My Saturn takes an extra half quart every oil change (4k mile OCI). It has done this with pretty much all oils. The previous owner of my car used bulk oil every 4k miles and even let it go to 6k miles a few times. This is with the SOHC engine with 107,770 miles on it as of today.

I believe the reason my engine uses less oil than others is because the previous owner and I do mostly highway driving. I'm convinced short trip driving and lack of getting the oil to temperature contributes some. Plus, I do rev my engine high sometimes. I'm convinced that driving like a grandma does more harm than good for our engines.

Another key thing. The previous owner was meticulous about keeping the oil topped off. If you let it get to 2 quarts in the sump that overheats the oil causing stuck rings.

 

[Doug Hillary]

Hi,
friendly_jacek – The two issues are sometimes mutually exclusive – at other times, directly related

In the case of “excessive” engine oil consumption, factors like poor ring pack/piston/bore design-production quality will perhaps be moderated but not solved by the lubricant used. “Excessive” of course being beyond that determined as acceptable to the engine’s Manufacturer

At least one Porsche engine family was recalled for insufficient oil control – it was primarily a piston and ring pack/position design issue that had not shown up in Lab testing prior to release to the public. A Recall once “excessive consumption” had been individually established resulted in modified pistons and ring packs being fitted. In this case the lubricant’s viscosity requirement was also changed from a 10W-30 to a 5W-40 viscosity (both Shell XMO synthetics)

I have seen almost the same situation in other engine families – VW for instance had a ring to piston assembly quality issue. Some ring designs and piston to bore irregularities affected at least one GM engine family in recent times – and a few in earlier times too!! The same applies in the world of heavy high speed diesel engines over several decades. CAD has greatly reduced the incidences!
Ring (and piston) deposits have always been an issue in engine design. This goes back to the very first “Otto” engines. It was also a very real problem in heavy high speed diesel engines. In some designs a certain piston deposit level became a requirement in the “fire band” above the top ring in order to “protect” it from excessive heat. Some engines requiring specific and quite high SA levels. Others were the reverse of course and had mandated very low SA levels

For instance it can take some minutes for the oil to exit the ring land area. Consequently it oxidises rapidly, has a greater additive depletion rate and is known to have a lower TBN and a higher acid level (TAN) than the lubricant in the sump. This is especially so at low engine revs. The composition of the lubricant will have an effect on its performance and the ACEA test protocols in particular address this – some have been added or changed in recent years. Individual Approval tests by engine Manufacturers see this area addressed as they see it. Using the correct viscosity as outlined by the engine’s Manufacturer is IMO quite critical in minimising deposits in this area

As the oil passes through the ring pack/piston area quite slowly, the viscosity the flow characteristics play a significant role. Wear particles (some combustion generated) are so small (some a product of the SA levels – some via excessive use of ZDDP perhaps) need to be swept from the area as quickly as possible. And of course increased flow reduces the rate of oxidation. So in some cases synthetics MAY offer some advantages over mineral lubricants!

While some lubricants may work to moderate one aspect of poor engine design their use may create other issues. IMHO it is always wise to use a lubricant that has been Approved by the engine’s Manufacturer – this will ensure that all know aspects of the engine’s function will at least be addressed

I have used HDEOs in petrol engines for several decades to minimise deposits. This was as a result of testing in a number of engine families conducted in NZ and in Scandinavia. At the time (late 1950s-1960s) PCMOs were of “variable quality” and HDEOs did the trick by reducing engine deposits generally! HDEOs were controlled to a large degree via CAT and other engine Manufacturer’s specifications. Porsche always used HDEOs as their factory fill from the 356 thru the 911s and almost until their commencing with synthetics (Shell) in the early 1990s. MB specified HD lubricants for many years in this era and of course HDEOs worked very well in air-cooled VWs too!!!
HDEOs also seemed to moderate some oil consumption matters in some engine families

What a bit of a waffle – I hope its of interest!

 

[d00df00d]

Originally Posted By: Doug Hillary
What a bit of a waffle – I hope its of interest!

Of interest indeed. Thanks once again!

 

[friendly_jacek]

Doug,

Many thanks for the insights. They confirm my suspicion that HDEO is the way to go.

There is one part I did not understand:

Originally Posted By: Doug Hillary
Some engines requiring specific and quite high SA levels. Others were the reverse of course and had mandated very low SA levels


SA = surface action aka detergents?

 

[d00df00d]

Sulfated ash I think.

 

[Doug Hillary]

Hi,
d00df00d - You are correct SA = Sulphated Ash

friendly_jacek - I hope it helps

 

[friendly_jacek]

No one took a shot at the insufficient oil drain holes in the piston ring region.

Why would one design engine without enough drain holes?
I understand Saturn has none?

 

[Doug Hillary]

Hi,
friendly_jacek - Each case will have a story

In the case of the Porsche engine familiy I mentioned IIRC the modifications included drilling more drain holes, altering the contact angle of each ring in the ring pack and the redesign of the oil ring. I think it was assummed that as oil was retained in the bores (silicate projection) that wiping would be simple as it was during testing. In reality only "field testing" produces absolutely concrete results - this is especially so in low volumn cars such as these

The move from a synthetic 10W-30 lubricant to a 5W-40 version was a part of the fix

As often is the case some engines did not exhibit high oil use in any event