Synthetic lubricants

JohnEd · March 28, 2009, 05:37:40 PM

I have read nothing but rave reviews about this stuff. It was also said that it lubed so very well that you could drop a sae grade and still be ok. My take was that using the called for grade in Syn would give you much better performance and it would run with less resistance AND have superior cold weather performance. At the rate that 2 strokes consume engine oil I thing that the crankcase is a bridge too far but all the other stuff would matter and affect MPG. So who is using it and where?

John

Chopper Scott · March 28, 2009, 05:51:59 PM

I've changed everything I own to synthetic oils except for the bus. The price for 11 gallons of synthetic oil versus the few miles I take the ole 8v71 doesn't pencil out right now. Hopefully some day I'll be able to cover a lot of miles with it and then maybe it will make more sense. Until then Rotella. Later

Sean · March 28, 2009, 06:13:05 PM

We put Transynd in the Allison and dropped several degrees of tranny heat. Can't tell you about MPG, but I won't run anything else in the tranny.

Just switched the differential to synthetic gear lube last week. Again, don't know if I will notice a mileage difference, but I am guessing I will never need to change the gear lube again.

I don't think you can get synthetic 40-weight that meets the DD 2-stroke specs. I would not vary from these specs one iota.

-Sean
http://ourodyssey.blogspot.com

luvrbus · March 28, 2009, 06:34:42 PM

FWIW guys Royal Purple make a synthetic straight weight 40w that meets DD specs. Cole used it in 8v92 for years with great success. good luck

WEC4104 · March 28, 2009, 07:15:26 PM

I am a believer in synthetic oils, for the RIGHT application and use. Several of my cars use nothing but synthetic. But when it comes to the bus, I lean toward conventional "dino" oils. First off, it is what they were designed to run on. If a DD can get 300K on a rebuild with a conventional oil, I can think of lots of ways to spend the extra coin that I would have to invest in the premium price of gallons of synthetic.

My Spicer transmission uses a conventional straight weight oil as well. Some folks have reported good results using a synthetic in this gear box. The problem is the condition of the seals. If the seals are older, the synthetics will leak much more.

luvrbus · March 28, 2009, 07:24:39 PM

Wec4104, if Detroit's were design to use the "dino" oil why does DD tell you can use the synthetic oil ,my manual dated 1988 states you can use it fwiw good luck

Chopper Scott · March 28, 2009, 07:43:55 PM

I guess I've read, and probably on this forum, that straight weight for the DD's unless you go to synthetic, then a multi viscosity is ok. Am I correct or is my wandering mind acting up again. Later

johns4104s · March 28, 2009, 08:12:16 PM

Some years ago I changed to synthetic Royal Purple as follows,

4104 Transmission, straight 50 weight ( or whatever was the weight that is recommended in my GM 4104 book) Made a huge difference. slide though the gears like butter.

4104/671 engine did very well.

4104 rear end, I was not sure if it would leak past the seals it did not.

Cadillac 145,000 miles did not change the oil filter soon enough, it took all the grim and dirt and dumped it in the filter, were it damaged the bearings,

WEC4104 · March 28, 2009, 08:16:18 PM

Quote from: luvrbus on March 28, 2009, 07:24:39 PM
Wec4104, if Detroit's were design to use the "dino" oil why does DD tell you can use the synthetic oil ,my manual dated 1988 states you can use it fwiw good luck

I am not saying that synthetics are verboten in all DDs. I would suspect that running a synthetic in newer 4 strokes might be a completely different story. I am looking at the DD recommentations for the 6-71 and 8-71 2 strokers. My line of reasoning is as follows... If a quality straight weight oil was good for 250K-300K miles back in the 1960s, today's improved straight weight conventional oils should be good for 300K+ miles. What will a synthetic buy you beyond that?

I look at it this way... My 6-71 was in-framed 2 years ago. While I'd like to drive it more, I'm happy to hit 12K miles/year. Even using conventional oils, I will either get another two decades out of the rebuild, or something will happen beyond the control of the motor oil.

Sean · March 28, 2009, 08:30:42 PM

Umm, folks, "synthetic" oils are petroleum-based. So I'm not sure what the reference to "dino" oil is supposed to mean. It all comes out of the ground. FWIW.

Quote from: luvrbus on March 28, 2009, 06:34:42 PM
FWIW guys Royal Purple make a synthetic straight weight 40w that meets DD specs. Cole used it in 8v92 for years with great success. good luck

I've looked over the latest lists of oils that meet the specs, and I don't see this product.

Royal Purple does not put their specs on their web site (why not?), although marketing hyperbole is in plentiful supply.

Can you point us at a spec sheet that says this oil is even CF-2 rated?

-Sean
http://ourodyssey.blogspot.com

luvrbus · March 28, 2009, 09:06:34 PM

Sean,I didn't have trouble finding the cf,cf2 ratings on the Royal Purple under the industrail division.Davenport worked for Stewart and Stevenson for 40 years and I know this guy would not use anything that would harm a 2 stroke.His 500 hp 8v92 would use 1 quart every 4500 miles this I know for a fact because he had S&S build me one and I use a quart every 4000 miles using Mobil 40w good luck

MattC · March 28, 2009, 09:46:45 PM

How odd!

I may have misread the document at this link, but it would appear that Royal Purple makes a Detroit Diesel lubricant.

www.ro-quip.com/Technical_Docs/Royal%20Purple/Industrial%20fluids/RP%20Motor%20Oil_ps.pdf

Hmmmm

JohnEd · March 28, 2009, 09:56:45 PM

Ha! I thought I would never see the day when our very own Sean would be wrong.

Ha! But wait, he hasn't answered yet.

Oh, the suspense of it all.

I thought the difference between 2 cycle oil and the 4 cycle stuff was "Ash content" and some other impurities. I don't think those are in Syn so it must meet the spec....all other things being equal. Catch that disclaimer?

They don't add stuff to CF2 do they?

Syn is much more temp stabilized. The only reason for 40 weight over 30 is viscosity. I think. Multi grade is peewater thin when hot and I can easily see where a high clearance engine would not do well with that condition. Syn multi grade might be ok if it's viscosity, at our operating temp, is near that of 40W Dino. Also a factor is the reduced temp added by the oil circulating. Sean said his temp dropped and syn is a superior lubricant so this is where the info I got makes sense....syn runs cooler and lubes better so you can run 20w Syn where 30W dino is specified and still get adequate lube and temp protection. That isn't my lie so don't beat me up but I have heard it more than once. Seems to make sense but I will let an engineer make that call. Bush made sense at one time to me as well and I am ever more humble and soft spoken in the presence of liberals as a result. Not to wax political, now.

John

John

John

JohnEd · March 28, 2009, 10:16:15 PM

MattC,

You da man! That Royal Purple site was really interesting. Seems that 15W40 beats straight 40 wt in all regards except ash spec. Then they turn around and spec 15W40 if you are not running low sulfur fuel ORRRR the temp hits -18C. They CALL for multi grade in a two stroke. You look at those numbers and tell me what they say to you....anybody! It is so late my eyes are no longer reliable and my fingers keep hitting the wrong keys.

Matt, thank you again. And I really mean it this time,

John

Sean · March 28, 2009, 11:17:46 PM

Quote from: MattC on March 28, 2009, 09:46:45 PM
I may have misread the document at this link, but it would appear that Royal Purple makes a Detroit Diesel lubricant.

www.ro-quip.com/Technical_Docs/Royal%20Purple/Industrial%20fluids/RP%20Motor%20Oil_ps.pdf

Thank you, that's what I was looking for.

Quote from: JohnEd on March 28, 2009, 09:56:45 PM
Ha! I thought I would never see the day when our very own Sean would be wrong. Ha! But wait, he hasn't answered yet. Oh, the suspense of it all.

John, I've been wrong many times, even on this board -- just check the archives.

I'm not sure, though, what you're referring to in this thread. I asked for a spec sheet, which I could not find on their web site (http://www.royalpurple.com/). Which is, indeed, full of marketing hype. (OK, I just went back and looked -- I also said I "didn't think" you could find a synthetic that met the spec.)

Quote
I thought the difference between 2 cycle oil and the 4 cycle stuff was "Ash content" and some other impurities. I don't think those are in Syn so it must meet the spec....all other things being equal. Catch that disclaimer? They don't add stuff to CF2 do they?

That's not the only difference. In fact, there have been several CF-2 rated oils over the years that have not met the DD spec for sulfated ash.

And, yes, all motor oils have additives, CF-2 is no exception.

Quote
The only reason for 40 weight over 30 is viscosity. I think. Multi grade is peewater thin when hot and I can easily see where a high clearance engine would not do well with that condition. Syn multi grade might be ok if it's viscosity, at our operating temp, is near that of 40W Dino. ...

Yes, the difference between SAE 40 and 30 is viscosity, by definition.

The chief problem with lower viscosity oils in DD 2-strokes, and that includes pretty much any multi-weight, to include synthetics, is that it is nearly impossible to maintain the oil film at the bearing surfaces in the crank and rod journals. Multi-vis oils are basically made from base oil of the lower viscosity, with additives to enhance performance at the higher temperature.

DD tried, for a while, to spec 15W-40 for the 2-strokes, with poor results. If anything, a synthetic will exacerbate this problem, not help it.

Quote
Also a factor is the reduced temp added by the oil circulating. Sean said his temp dropped and syn is a superior lubricant so this is where the info I got makes sense....syn runs cooler and lubes better so you can run 20w Syn where 30W dino is specified and still get adequate lube and temp protection.

Well, maybe and maybe not. The engine is designed for the oil to run at a certain temperature, so you don't really want it to be below that design threshold.

Tribology is, of course, a science, but to me (and perhaps most of us on the board) it's a black art. I don't pretend to know even a small fraction of what tribologists deal with on a daily basis. I try to know just enough to keep my own engines out of trouble, mostly. But hey, I've dirted my DD out twice, so I don't even have a good track record with that.

What I do have at hand, though, is the DD spec, and I know I am safe (mostly) by sticking to their recommendations pretty religiously. Which is why I always ask to see the specs on any fluids going in to my engine. I'm glad to have the sheet now for another product, which is apparently esoteric enough that I have not seen it on any of the lists circulated periodically of DD 2-stroke compliant oils. It will go in my file.

That said, I'm not sure I'd spend extra on synthetic for my 8V92, given how much oil it goes through and the fact that bearings are cheap and easy to replace, whereas liner and ring wear is the real driving force behind overhaul intervals. Synthetic may help a tad here, as well, but I suspect the oil performance is far overshadowed by other factors such as combustion air and fuel quality. Remember, too, that contaminants in the oil play a major role, and it does not matter how good the oil is when you put it in -- it's still going to get contaminated in operation, one of the 2-stroke's big weaknesses. So I favor spending the money on shorter change intervals for oil and filters instead. JMO.

-Sean
http://ourodyssey.blogspot.com