Synthetic Oil for 6v92's

[Nimitz3]

Is there any benefit to using synthetic Rotella in these engines. Also does anyone use Lucas Oil Stabilizer. Thanks in advance

[Genesis]

Note that 6v92s must run straight weight 40.

All the Rotella T synthetic I've seen is 15W40. This is a CH-4 oil and is NOT APPROVED for 2-stroke engines. You need a CF-2 (or later, but with a "-2") rated oil.

Besides likely leading to low oil pressure when hot and consequentially eating your mains, it also has too high of a sulfated ash number for 2-stroke use and will likely trash your valve seats over time - if the mains don't quit first.

In a word - don't.

[bobk]

Note that 6v92s must run straight weight 40.

All the Rotella T synthetic I've seen is 15W40. This is a CH-4 oil and is NOT APPROVED for 2-stroke engines. You need a CF-2 (or later, but with a "-2") rated oil.

Besides likely leading to low oil pressure when hot and consequentially eating your mains, it also has too high of a sulfated ash number for 2-stroke use and will likely trash your valve seats over time - if the mains don't quit first.

In a word - don't.

I just looked in the manual for my 6V92 TA 425 HP and is said "Detroit Diesel Allison (1981 engines) now approves and RECOMMENDS (emphasis is mine) the use of the new generation of 15W40 oils". Must have sulfated ash between 0.5 and 0.85% and meet API CD/SE. It goes on the say that DD continues to approve the use of straight weight oils. (My mechanic who is an ex 20 year Johnson and towers mechanic recommends straight 40 weight, but it sure is hard to find outside of Florida unless I pay J&T $12/gallon.)

Does Rotella T 15W40 meet this? If so, the ability to get it at Walmart is a real plus. And how aboout the transmission, Allison M15? Same oil?

I do not have a owners manual for the 2001 12.5 KW Westerbeke. Does anyone know what is recommended there?

Bob

[SKYCHENEY]

This was recommended by DD for a short time, but then they found out it was a mistake and revised the specs back to straight weight. I know from first hand experience running Detroits in our business during those years. It was a complete failure. Don't use multi-weight oils in them!

[Genesis]

You will destroy the Allisons with multigrade in them, and the engines too. Don't do it!

The generator probably wants (or will be good with) the 15W40, but you need to find the engine manufacturer's recommendations......

[Freebird]

Note that 6v92s must run straight weight 40.


Karl,

I have 12V71N's in my 58TC which are, of course, also two strokes. I know for a fact the previous owner used Rotella 15W40 in them. I use this same oil in my company trucks, but they're not two strokes. Should I change the oil to a straight 40? Could there be any connection to the multi-grade oil with my recent "self-healing" episode of not having forward gear on my starboard?

[Genesis]

Detroits and Allison gears DO NOT like multi-weight oil. Get it out of there. Exxon XD-40 is what I ran; Delo 100 is also good if you can find it (I used to run the Delo but switched to XD-40 when the Delo got hard to source in 5 gallon pails)

[Boss Lady]

The oil specification is critical for DDs, the ash content is just one of the issues you must pay attention to. There are a couple of oils available that meet the specifications. The multi-weight oils are designed for cold weather climates where there are advantages to them when the temperature is below freezing. Since your boat is sitting in water that rarely gets colder than that, there are no advantages to multi-weight oils only disadvantages. The lower viscosity components do nothing for you at elevated temperatures except lower the overall viscosity and its' performance compared to straight weight oil is not a performance test I would like to experiment with. Even on a road vehicle I would switch it to straight weight in the spring. Unless you want to be the person paying for your own R&D it is generally wiser to use the approved oils. Things like gaskets and clutches were made many years ago of different materials than are used today, the new lubricants may actually attack and breakdown older components. Newer engines may use synthetics and lower viscosities, but those things have been engineered to work together.

[MikeP]

As Sky mentioned - that quote about using approved multiweight oils is also in the V71 engine operators manual from the late 70-s early 80s. It is NOT in the current latest V71 engine operator manual nor is it in the latest V71 service manual. Obviously it sounded like a good idea at the time which proved to be NOT a good idea...

[Jaxfishgyd]

When we bought "No Dial Tone" in 2000, both engines were majored (as in, only the block was left in place, EVERYTHING else was rebuilt/replaced, and paid for by the previous owner).
I would come by about every other day to check on the progress and bring the DD techs 12 packs of soda and lunch from Subway or some other place.
They both told me almost every trip that I would use only 40w oil.
Cost the seller a ton of money (but then again, he ran the motors with NO oil in them causing them to screw up).
I see one of the techs several times a month and our standing joke is " you got oil in the engines"..... And yes, its 40w only......