Oil usage

[Slade1948]

What would be considered an acceptable amount of oil usage for a two cyl Diesel engine.

[GordMay]

Greetings and welcome aboard the CF, Slade.

[Rhapsody-NS27]

What kind of engine are you talking about?

I have a Yanmar 2GM that holds about 2quarts. Is that what you're talking about or are you having to keep adding oil periodically?

and welcome to CF.

[Slade1948]

Yes I add about 8oz every 20 hours or so

[Crew of Turning]

How old is your machinery and what make is it? If older using 8 ounces/20 hours or one imperial quart per 100 hours would be acceptable. In our case the engine is a 1977 Yanmar 2QM20 rebuilt in 2004 and uses about a quart per 100 hours. This translates to us as a quart per sailing season. Some consumption should always be expected.

[Slade1948]

It's a 1987 universal marine M12. As far as I know it has never been rebuilt. Thanks for the info.

[Stu Jackson]

I have an M25 Universal, 1986. Uses NO oil between changes.

[Mystic38]

if you are spewing smoke ..then its an issue..

but if not, i suspect there is a spec for consumption of oil for your engine if you search enough.
half a pint every 20 hours is more than a quart per 100 hours.. and that is high in my book and signifies engine work coming up.
i have a 1993 westebeke and it uses zero oil between changes.

[Slade1948]

No smoke or blowby.

[Slade1948]

How many hours do you put on in the course of a season

[a64pilot]

Just an opinion, but ANY Diesel, oil consumption is no issue, if it makes good power, starts easily and isn't blowing an obnoxious amount of blue smoke.
Years ago, I read a study done by the Brits right after WWII, on oil consumption, and one of the things they found was that once an engine began to use a significant amount of oil, the upper cylinder wear reduced drastically.
Now in the 21st Century modern metals and machining have enabled engines that consume essentially no oil, so we have become accustomed to no oil consumption.
An average small airplane that consumes as much as a quart every ten hours is considered normal.
If it starts easily and isn't smoking up the neighborhood, I wouldn't worry about it.

If it's an old school engine and has a one piece oil control ring, even if it's in perfect shape, it will consume oil.


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[Slade1948]

Thanks very much. You and the first reply are the only ones that make any sense. I hate to post anything on these sites because there are so many doom and gloomers telling your boat going to sink or your engines going to blow up when you have the most insignificant problem. I often wonder how they leave the dock. Burning a quart of oil every 100 Hours or so amounts to about a quart of oil every 5000 miles in a car. And I know from working with diesels for years that they burn more oil than cars. I was just trying to get an idea of usage and was told that I was going to need a build real soon. The engine doesn't smoke, has plenty of power and no blow by. It just uses a little oil. It's no big deal it's a 30 year old diesel.

[topmast]

What oil have you been using? Maybe a multi wt like 10 w 30 will do you better.

[Slade1948]

Right now I'm using a 30 weight oil. A 10W 30 is actually a 30 Wt oil with characteristics of a 10 Wt oil when cold providing better flow and therefore better distribution throughout the engine in cold weather as well as making it easier to start in cold weather. Since I only use my boat in the summer this is not a consideration and the fact that the oil is thinner for a period of time this would probably exacerbate my oil usage.

[a64pilot]

Go to straight weight 30.
In theory multi viscosity oils act like the higher number when hot, but our little Marine Diesels don't get that hot, so your running a less than the high number oil. Average modern automobile driven normally will have an oil temp in the low 200's, our little Diesels usually don't see much if any over 180. Most of us will never use our boats in temps that require a multi vis oil.
If you want to run a multi vis, go for a 15W-40.
My 30 yr old 4JHE using Shell Rotella T6 synthetic 5W-40, burned about a quart every 100 hours and didn't smoke, but left a greasy stain on the stern when I had a following sea. Now Rotella T6 sun is an excellent oil, just I think maybe a little thin for my old Diesel.
I am now using Rotella straight 30W at about half the oil consumption and no greasy stain.
Now I am a strong proponent for Syn oil, I am not sayin Syn is bad, it is not, it is I believe superior, but my old motor, the 5W-40 is just too thin, and or possibly doesn't burn at the temps I have?


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