oil education

[demodriver]

I saw in another thread about the 2 strokers using special oil.

This is my first detriot so some do's and dont's would be great. I was just going to use rotella that I use in all of my equipment.

If theres info already on here let me know and I will deleate this.

thanks Eric

[Lin]

There should be a lot in archives about this, but the search feature is sometimes not that great.  If you want to try it, use the search button on the menu above.  It works better than the search window.  The short answer is that DD recommended a straight weight oil with below 1% ash content-- oils that meet the old CF2 rating.  There are a couple available although you generally have to look for it.  Chevron Delo 100 (not 400) is one of them as is Exxon XD3.  Shell Rotella is another although just barely.  Most will tell you to use straight 40.  There are those however that say it is no longer necessary to follow those specs, and that other modern oils are okay.  I am not an expert, but will err on the side of caution and use the original spec'd oil.

[bevans6]

It's a little bit of a complicated subject due to us not really being chemists and lubrication engineers and relying on experience, Detroit Diesel recommendations from years ago, and not really understandng the advances in modern, current lubrication technology.  So I will say there is no final answer.

CF2 was the oil specification for 2 stroke diesel oil for DD engines.  It's been obsoleted and as a test no longer exists, but oils that were tested and manufactured to that spec still exist, still meet the requirements and are still available.  It is a single weight oil, usually SAE 30, 40 or 50, has low ash requirements and several other things that make it probably the safest choice for two stroke DD engines.

Multi-weight oils like the typical 15W-40 used to have problems that caused issues in two strokes in some conditions, so were not recommended.  That included a high ash content, viscosity modifiers that broke down prematurely in the operation condition inside a two stroke, leading to buildup on rings, combustion chamber, generally poor performance and premature engine failure or need for rebuild.  The main issue is the combustion cycle does not have an exhaust stroke to promote cooling of the piston/chamber so the piston/ring package runs far hotter in a two stroke than in a four stroke.  Also the bearing loading is higher, again because every stroke is a power stroke and there is no rest stroke to rebuild the hydrodynamic oil cushion inside the bearings.

Modern multi-weight oils have acceptably low ash content, have far better viscosity stability, don't break down as fast, are used successfully by many including the US Military, and are probably OK.  Yet the unknown is that they haven't been tested or approved by DD, or by any industry standards body, for use in two strokes.  So while lots of people use modern, current 15W-40 oil quite happily, most advice, and the advice I follow, is to search out the CF2 spec single weight SAE-40 oil and use that.  Not that big a deal, I can still order it and get Rotella or Delo, and Walmart carries their brand on the shelf in 5 gallon buckets for $40 at my local store.  I would say that if you do decide to use 15W-40 watch out for low idle oil pressure, oil pressure in general, changes in oil pressure readings over time, and change it twice as often as normal, what ever normal is.  Also make very sure that you regularly run the bus hard enough to get the oil temp up over 220 degrees for a decent period of time to get rid of  water/condensation buildup (always good advice to run it hard every once in a while, lets it know you love it).

My two cents on this...

Brian

[luvrbus]

Read the jug if says meets the MTU 1 (owners of the 2 strokes) requirements your are good to go C rated oils have been less than 1% ash now for several years and fwiw the MTU 2 engines are 4 strokes.
Me I prefer Delvac1200 Mobil/Exxon that is what they left the factory with and still do today

good luck

[lostagain]

In Canada, Petro-Canada makes an oil specifically for 2 stroke DDs. Called "Dieseltonic", it is a straight 40w, low ash, etc, available at Petrocan bulk plants across the country. If not on the shelf, they can order it.

JC

[lostagain]

This the page about it on their site:

http://lubricants.petro-canada.ca/en/products/606.aspx

JC

[demodriver]

thanks for the replys guys, I tried the search to start with and got NO results with about 5 different word configurations.  I then did another search and got all the info I needed. I spent about 2.5 hours reading about oil.  I think I have it figured out now. 

Low ash content
single grade, 40w

[JohnEd]

Not so fast, Grasshopper.  I attended a "oil discussion and presentation last year at Rickreel, Orygun.  The speaker was a highly regarded professional.  Two things came out of this for me. One....SYNTHETIC has only one drawback.....cost.  Otherwise it outperforms Dino products in every regard and shames them deeply.  Two...Not all the MTU-1 oils are equal.  Some brands are "equaler" than others.  That "less than 1% ash" spec is a real bugger.  Delo 100 is often tested at .5%....half the max requirement.  Others that carry the 2 stroke approved rating are sold with a .99% content that barely meets the spec technically but misses the mark in intent.  That oil is out of spec after a few miles as ash is deposited in the oil during usage.

DD 2 strokes are notorious for leaking and burning oil.  The cost of syn for those engines is out of the question.  Still, some rare owners have their engines in such great condition that their oil consumption is next to nil and they could use syn cost effectively.  There is no law that says these engines MUST consume oil.  Find the leaks and plug'em.

John

[Tikvah]

While we're on this topic.... how often do you suggest changing the oil?  I'm sure there are variables, like miles, hard mountains vs easy miles, off time, etc.  So, give us the scoop..... what's the suggestion?

[artvonne]

  There was once a discussion around the Mercedes gurus asking about oil changes. The concensus was if you never shut it off, didnt idle it too much, and drove it reasobably hard enough, 10,000 mile oil changes would be fine. Some of the big OTR rigs are running much, much farther than that.

  There are really only two things that happen to oil. One is that it loses viscosity as the additives in the base oil get used up and/or sheared, The other is the crud the oil picks up everytime its starts.

  When you start a cold engine, the heating effect is so rapid a great deal of moisture is created and precipitates out into the oil. As long as the engine runs long enough it cooks off that water, but acids are formed as a consequence. After a while you start to have some real gunk in there and eventually it will start leaving behind deposits of sludge.

  It was pointed out some times ago that one of the big issues with the 2 stroke Detroit in regards to oil are the cylinder transfer ports. As each piston goes up and down, the rings pass over those ports twice, and this is an incredibly high shear area for the oil. Think giant heavy duty industrial scissors. Four stroke engines simply have no equal to compare this effect to. And multi grade oils, which by their very nature MUST have more additive to hold thier viscosity, are broken down rapidly, effectively sheared to smithereens, in a two stroke Detroit, rendering the multi grade a single grade oil with the same viscosity as its base stock. So in the case of a 15W40, you now have 15 weight oil with a bunch of useless garbage mixed in with it. And the shearing effect is so great and so rapid, that the engine can effectively destroy a multigrade oil in just a few 100 miles.

  There was an interesting test done a few years back by Mercedes, it a was a wear test of multi grade oils against straight grade oils. The results showed a straight 30 weight oil to have the least engine wear over any other grade. But before you get excited, they were talking fractions of percentages, maybe the difference between getting 500K out of an engine and 525K miles.

  As far as the dino/synth argument, there has never yet been any data to show any  engine will last any longer on synth than it will of dino. Ive seen many many, old Mercedes with over 500k on the original engine running nothing but Kendall thier whole life. Good oil is good oil, and changing out gunk is the key to long life in any engine, no matter what kind of oil you use. Regardless, these engines seem to want straight 40 weight, and thats what ill put in mine. As Scotty was fond of saying, you cant change the laws of physics.

[luvrbus]

JohnEd the new Delo 400 LE 15/40 is less than .05 ash all C rated oil has to be less than .05 ash by years end you read all the specs on 400 and the 100 Chevron they have the same additives Chevron even boasts about the ashless additives in the 400 then when they get to the spec sheet they say 1.37 ash content in the 400 it is all hipe and bs to sell different products for more cash
DD 2 strokes where around for 30 years before the Delo 100 hit the market for the 149 series a different animal all together # 1 fuel only or kerosene.
It's all bs John back when the fuel was used with high sulfur contents like the off road fuels you had to use a higher ash content oil to make the TBA numbers jive even tells that in the DD bible  
And your right the 2 strokes don't need to burn oil I been around 8v92's that use a gal every 12,000 miles between changes. A 2 stroke will burn oil at a high engine operating temperature around 200 degrees then they will burn a gal every 1000 to 1200 miles.
Then I have friends that use the synthetic 15/40 with great results in their 2 strokes.  
10 to 15 thousand miles is about the time I change oil but the book says 20,000 miles Tikvah a oil sample will tell you for sure on your engine it changes with people's driving habits and your fuel supplier.
Art the oils rings on a 2 stroke never pass over the ports on a 2 stroke fwiw


good luck

[demodriver]

Ok, So does Rotella make a good oil to use in my bus? I have had three cummins trucks now and have always ran rotella in them. The first one had over 500k on it and the engine is now in a museum, litterally. I also run it in my dozer and excavator. So I am pertty fond of it. Its usually easily found also.

I think that I have read so much that I have myself confused now lol.

[lostagain]

Every 250 hrs. That is about 15000 miles, give or take.

JC

[RJ]

Ok, So does Rotella make a good oil to use in my bus?

Yes, Rotella's fine, just use the straight 40wt version, not the multi-weight.  The ash content is a little higher compared to Delo 100, XD3 and Delvac, however.  Probably not a significant issue for RV applilcations.

As Paul (Artvonne) pointed out above, the viscosity index improvers (what makes a 5w/40w oil act like a 40wt) break down rapidly in a two-stroke, so you're left running basically a 5wt oil.  There's a link to an article about this phenomena written by an oil company engineer in the archives over on the other big bus bulletin board, IIRC.  www.busnut.com  Has a good search engine, so you should be able to find it.

The straight 40wt will be fine in your other diesel engines, too.

FWIW & HTH. . .

[demodriver]

I usually run the 30 wt in everything so switching to 40 isnt that big of deal.

thanks Eric