DD 6-71 TIBs and Delo 100 vs Delo 400 lube oil.

[Passages]

Up in the Northeast we use Valvoline All Fleet plus 40 wt. CF-2 rated and readily available at NAPA. Reasonably priced at $45/bucket.

 

[MikeP]

I know that the DDs are to use CF2 oil - I use Rotella which our marina store stocks and sells for 45/pail. What I don't understand is why CF2. The oil is not "two stroke oil" per se - it is not mixed or ingested with the fuel. It is for lubrication. What is there about these engines that make the bearings and other friction surfaces require different oil than other engines? It frankly makes no mechanical sense to me (though I have to admit, I don't care enough to actually research this).

 

[SKYCHENEY]

If you are still using Delo 400, check out this link to the Sams Marine tips and tricks section. It is the actual recommendation from Chevron not to use this oil in 2 cycle Detroits.
http://www.samsmarine.com/Manuals/Chevron/Chevron/Delo 400.htm

 

[Genesis]

I know that the DDs are to use CF2 oil - I use Rotella which our marina store stocks and sells for 45/pail. What I don't understand is why CF2. The oil is not "two stroke oil" per se - it is not mixed or ingested with the fuel. It is for lubrication. What is there about these engines that make the bearings and other friction surfaces require different oil than other engines? It frankly makes no mechanical sense to me (though I have to admit, I don't care enough to actually research this).

Two things:

1. The point-loading on some lubricated surfaces requires higher shear stability than multi-grade oils can handle (with the exception of a few synthetics, such as Delvac-1) Using multi-grade oils will EAT CAMS. Camshafts are a royal bitch to get in and out of these engines. 'Nuff said.

2. The sulfated ash issue is huge. Exhaust valve deposits will lead to exhaust valve leaks, and those lead directly to burned exhaust valves. That ends up costing you a cylinder head.

I also own a TDI Jetta. It has fairly generic oil requirements, other than the need for a full-synthetic due to higher fire deck temperatures occasioned by emissions regs and the engine's design to deal with them. I run Delvac-1 in it, which meets those requirements.

The next year's engine is a unit-injector motor and Delvac-1 does not meet that engine's requirements for the same reason the 2-stroke Detroits have problems with many oils - valve train pressures are too high and you'll eat camshafts if you don't run the specially-rated oils they recommend!

 

[MikeP]

Two things:

1. The point-loading on some lubricated surfaces requires higher shear stability than multi-grade oils can handle (with the exception of a few synthetics, such as Delvac-1) Using multi-grade oils will EAT CAMS. Camshafts are a royal bitch to get in and out of these engines. 'Nuff said.

2. The sulfated ash issue is huge. Exhaust valve deposits will lead to exhaust valve leaks, and those lead directly to burned exhaust valves. That ends up costing you a cylinder head.

I'm sure your points are good ones, but both of these items are issues with any engine - I'd think that the cam loading on a performance-oriented gas engine is much higher than it is on these DDs. Cam loading is determined by the tension of the valve springs which is, in turn, determined by the max RPM of the engine. High RPM engines need higher tension springs. I wouldn't think that an engine with a max RPM of 2500 RPM needs much of a spring to follow the cam. Although, as I think about it, it is quite a heavy valve train which, in turn, would require more spring tension. But is it notably heavier than a 4 stroke diesel?

Certainly exhaust valve deposits can be a big problem but if they are caused by lubricating oil, it seems to me it's the result of poor valve seals and bad valve guides. I realize that DDs are anything but "tightly clearanced" so perhaps the requirement for CF2 has more to do with loose clearances than anything else.

In any case, I am just curious. I am not suggesting and would never use un-approved oils.

 

[Nonchalant1]

I'll bet even the California guys can get Detroit Diesel brand 40# oil from Dteroit Diesel, if they can't get Delo 100 there. I don't mind paying extra when I know it's the right stuff. If it hadn't been for the flyer on Sam's Marine website, I would not have known not to use Delo 400, but I'd have been OK because I just use the DD brand oil they recommend. We're all different, I guess.

"You pays your money and you takes your chances."

Doug

 

[Genesis]

Two differences....

Its not the valve springs, its the injector. The load on the injector cam and follower is WAY higher than on a regular valve - that's where the problem lies.

The issue with exhaust valve deposits isn't from the guides and seals. Its from lube carry-up through the airbox ports, which doesn't happen on 4-stroke engines but does on a Detroit, because the only ring left when the piston is up below the airbox port is for oil control.

Then the piston comes down and that oil which was left on the port gets blown into the cylinder.

This causes significantly more oil consumption in a Detroit than in a 4-stroke engine (typically about twice as much) - and that's where the sulfated ash problem comes from.

This is why the spec calls for one half of that allowed in a 4-stroke oil - double the "normal" burn through the engine, half the sulfated ash limit.....

 

[Ross Macdonald]

After reading all the info. on this thread, I thought my tech knowledge was pretty good. I'm not even in the ballpark with some of you guys. I appreciate some of the tips on getting the proper oil here in So. Cal. It looks like I will order it from San Diego Marine exchange. For all of you on the other coast, this is probably the biggest and best Marine Harware store out here. The downside to all this is I just did a complete oil and filter change with the wrong oil! You can imagine how many gallons a 12V 71 takes.... So I now have 2 hrs. on this change and will have to dance the dance over. I am still using the Delo 400 in the trannies. (Twin Disc MG 514). I assume that's ok. If I have been using the Delo 400 over the last 4 years and have put 700 hrs. on 5 oil changes, and assuming the oil causes these problems, what damage has occured and what signs during operation would be evident?

 

[MikeP]

Genesis - excellent!


I had TOTALLY forgotten in the heat of the moment that the DD injector is activated by the valve train so absolutely - the valve train load would be dramatically higher than one that only activates the valves.

Also, it makes sense re the ash - since the manufacturer designed these engines to burn twice as much oil, we need to cut the amount of ash in the oil in half.

I love it when a technical explanation comes together!

 

[Eufaula]

Ross,
I would not change the two hrs. oil change let it time out on your oil change sked. and then shift to the 100. Your V-12's are very durable. I ran V-16's generators at 1800rpm year in and out with 3/4 load with maintenance done on time, I pulled no cyl. heads in five yrs. my problem area were turbos, and crankseals however these were due to normal wear and tear. Oil used was Delo 50#. The company recommended Delo #50 because it was req. for the main engines EMD'S V20 647. oil storage tanks was crittical. James

 

[spartonboat1]

Re: oil turning black, Coast Guard diesel tech tells me a diesel in good shape should not necessarily have its oil turn black. My rebuilt 6-71 with about 300 hours usually stays clear over a 25-50 hour period; at times I almost cannot see it on the stick. I have also started to use the 1,100rpm warm up idle speed (per another post) and that seems to help keep the oil clear; the rebuilt engine smokes maybe 5 secs or not at all if fully block heated. The orig hours engine stops smoking much more quickly.

The orig hours engine turns dark after 20 hours, but does get pitch black like many diesels I've seen.

FWIW...

 

[Genesis]

Mine have ALWAYS turned the oil black immediately. Right after rebuild and to this day.

Some do, some don't. My Yanmar genset engine gets dark but not pitch-black.

My 6v92s have always done it, and I suspect always will

 

[Ross Macdonald]

James... Thanks for the info. This season I'll probably put about 90-100 hrs. on the old 12s. Knock on wood, but these engines have really run well, almost no smoke on start up, light right off, and, as I said earlier, burn about 1 qt. every 30 hrs. Since I run long distances at 1450 RPM, I usually run them up about every 4 hrs. to 1850 for about 5-10 min. so I don't load up the turbos and then dial it back. Especially after watching the floscans at 1850, I usually want to get back down to 1450. Once again, thanks for all the input. Ross

 

[Passages]

The search function works!

Still going thru unexplored cabinets on Aphrodite and found a full jug of Delo 400 straight 40. Was rated CF, not CF2. Was not sure if it was ok in 8-92's so came here. Ran search and this 12 year old thread answered my question.

Now I'm wondering if it's ok to use in the tranny. I'm thinking yes.

 

[racclarkson@gmail.com]

The search function works!

Still going thru unexplored cabinets on Aphrodite and found a full jug of Delo 400 straight 40. Was rated CF, not CF2. Was not sure if it was ok in 8-92's so came here. Ran search and this 12 year old thread answered my question.

Now I'm wondering if it's ok to use in the tranny. I'm thinking yes.

It's OK for transmission as long as 40Wt. motor oil is spec'd. I use Delo 100 40 wt. in motors and 400 40 wt. in the ZF gears.