Single grade oil?

[Han]

Hi All,

We have an older (1978) Sabb diesel in our new (to us) sailiboat. I was planning to change the oil last weekend, but I ran into a bit of a roadblock. The manual says to use SAE 10 (for below 10C) and specifically says DO NOT use multigrade oil. However, I'm finding it pretty difficult to find SAE 10 oil. Has anyone else run across this problem? Would it be a big problem to put a multigrade oil in? I'm no mechanic and I'm not sure if there have been big changes in oil technology since 1978, so any advise is appreciated.

Thanks!

[Microship]

I am not a diesel expert by any means, but this question just came up last week at a 3-day diesel maintenance class in Seattle taught by Larry Blais. Same advice: no multi-viscosity oils as they have less lubricity (he said that around here, in Puget Sound, 30 weight is fine, and recommended Delo 400 as his favorite).

Cheers,
Steve

[David M]

I just got a new set of diesels from Cummins that require multi-grade. Why?..no idea.

[delmarrey]

Internal boat motors should not need multigrade oils. The temperature does not fluctuate inside a boat like on car/trucks. The lows shouldn't be so low that a multigrade would be necessary. Maybe on a boat in Alaska

[Kanani]

Originally Posted by Han

Hi All,

We have an older (1978) Sabb diesel in our new (to us) sailiboat. I was planning to change the oil last weekend, but I ran into a bit of a roadblock. The manual says to use SAE 10 (for below 10C) and specifically says DO NOT use multigrade oil. However, I'm finding it pretty difficult to find SAE 10 oil. Has anyone else run across this problem? Would it be a big problem to put a multigrade oil in? I'm no mechanic and I'm not sure if there have been big changes in oil technology since 1978, so any advise is appreciated.

Thanks!

The manual that you are reading is for a new engine.

You should have no problem with 20-30 weight. Just make sure that you get diesel oil. Look for the grade on the side of the container. It should start with "C" for "Compression" combustion. It should not start with "S" for "Spark" combustion.

I have always read that multi-grade oils are not acceptable for diesels because of the higher compression ratio and larger loads on the rod journels. The stress is more evenly spread with single grade oils. With multigrade, its like having different sized balls in a ball bearing. Each of the larger balls will have to share more of the load.

[Nauticatarcher]

Older diesels generally dont like modern high detergent multigrade oils lookm for a SAE rating of "CC" or "CD" I use BP Vanellus C3 mono 30 "CD" rating in my Ford Lehman and used to use Vanellus c Mono 30 "CC" rating in my Gardner

[Alan Wheeler]

I wrote a lot of info on oils a long time back. I will see if I can dig it up from the Archives and make it a Study Hall article.
The main concern with a multi grades are that multies are not stable. A mono is a very stable oil. A 30W oil is the most common to use in a Diesel. It would have to be damn cold to use a 10W mono. That stuff is what I use in my steering. It is very light. I could imagine if the Diesel was a tractor and so the engine was exposed to the elements. But in a boat engine room, I don't think so. Or are you an icebreaker working in the Arctic?

[Ex-Calif]

As usual Wheels has sound advice. I can't think of a reason that they specify "only" 10W. Usually there would be a table of ambient temperatures vs. viscocity. Maybe in Norway 10W is appropriate but I wouldn't run anything that thin here at the equator.

[Ex-Calif]

OK - I can't leave things alone. I googled a bit and came up with the Saab Marine website. This is the online manuals page

Sabb Motor

You don't say what engine you have - The 2H is 18hp here is the manual (warning it is about 5 meg)

http://www.sabb.no/eng/viewfile.aspx?id=71

- the lube page says:

"below +10C = 10W
+10C - +30C = 20W
Above +30 = 30W

Do not use multi-grade"

I'd put 20W in it. If I couldn't find 20W I'd have no problem using 30W especially as you probably sail mostly in the summer anyway.

If you have the 2G (22hp) or 2J (30hp) which I doubt the manual is here - Again about 5mb

http://www.sabb.no/eng/viewfile.aspx?id=68

[CSY Man]

Hmm, I have been using multigrade all the time:

Shell Rotella 15-40. Never heard of an issue with it...

I'm not sure if there have been big changes in oil technology since 1978, so any advise is appreciated

Me thinks there has been big changes in oil technology in 29 years.
Better lubricants with more additives for longer lifes, etc.

[Han]

Thanks for all the helpful replies. After reading everything posted here, I'll try looking for 20W diesel oil and failing that, I'll get 30W.

Thanks again!

[Alan Wheeler]

Me thinks there has been big changes in oil technology in 29 years.

Yes but......It's not the fact that oil has gotten better. It is about what the manufacturer specifies for his design.
Oil companies don't make oil and say, hey Mr Cummins, use this oil. The engine manufacturer say's to Mr Oil company, we need and oil to meet this spec. Mr Oil company goes and makes an oil that meets or exceeds that spec. That spec is usually published on the back of the container. The "my oil is better than yours" part comes into the way the packadged oil is marketed. Like, "magnetic" for example. It has something in it that makes it cling to parts, so they say.
One thing to understand about multi grades is the wide grading does not mean the oil is better. It's a bit of misuse of the spec by marketing companies. The weight of an oil is determined by the time it takes for a measured amount to pour through a test hole at a set temperature.

[Kanani]

Originally Posted by Alan Wheeler

Yes but......It is about what the manufacturer specifies for his design.
Oil companies don't make oil and say, hey Mr Cummins, use this oil. The engine manufacturer say's to Mr Oil company, we need and oil to meet this spec. Mr Oil company goes and makes an oil that meets or exceeds that spec.

Surely you don't really believe that do you?

Are you suggesting that any oil company is going to design a specific formula for any individual engine manufacturer?

I know for a fact that doesn't happen for GM. I can't emagine it happening for...say...Cummins.

Maybe I mis-understood your point....???????

[Alan Wheeler]

Yep that is exactly what happens. Of course, oil manufacturers will design there own formulation of an additive pack. But the engine manufacturer specifies the minimum requirement for there engine.

OK, if ya really want to know about oils, I have just placed three links in the Study Hall. One is to the Wearcheck site and two are to articles within that site. It is very good reading and way more info and expertese than I could ever concider doing just to if I were to write something myself.

[Sandero]

15W40 seems to do the deed.