Common oil for these 3 engines?

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dovekie

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I have three comparatively lightly used small diesel engines which I want to run for many years if possible. I service them myself annually, following the relevant manuals, and the oil change for each always made because a year has passed rather than because of the engine hours run. My question is: is there a single multgrade oil I could use for them all? It would make things simpler for me and I could look to buy in bulk too (205 litre drums) as long as the stuff keeps several years.

The information I have is:

Boat, Beta 38hp, 2 yrs old, naturally aspirated, kubota block, runs 20-40 hours per year, Scottish West coast, including winter.
Beta recommend
-30 deg to 0 deg ........10W30
-15 deg to 15 deg ......15W40
0 deg to 30 deg ..........15W40
25 deg and over .........15W40

Small tractor: Yanmar 35hp engine, 8 yrs old, naturally aspirated, runs 60-100 hours per year, Cumbria, including some winter use, down to say -5.
Italian manual translated recommends 15W40, nil else mentioned
Yanmar manuals online say
10W below 10 deg C,
20W at 20 deg C,
30 or 40 at 20-35 deg.

Lawnmower, Kubota 21 hp, 3 yrs old, naturally aspirated, runs 40-50hrs per year, mainly summer of course, Cumbria.
Manufacturers recommend
10W30, or 10W40 - the latter if ambient temp >30 deg C.

I hope that I can use 10W40 in all of them, and that a cheaper (mineral?) one may suffice because I am not running for long hours before changes. But, clearly it is a very technical topic - any advice appreciated. (I always try run the engines until warm, and under load by the way - as advised by forumites.).
 
We run a boat (BMC 1.5 diesel), 2 diesel cars, 1 petrol car, 5 motorbikes and a lawnmower and after some research I found that Shell Helix Plus 10/40 is the right spec for all of them. I buy it in 20l drums from Emo Oil and it's about £3 per litre.
 
dovekie said:
I have three comparatively lightly used small diesel engines which I want to run for many years if possible. I service them myself annually, following the relevant manuals, and the oil change for each always made because a year has passed rather than because of the engine hours run. My question is: is there a single multgrade oil I could use for them all? It would make things simpler for me and I could look to buy in bulk too (205 litre drums) as long as the stuff keeps several years.

The information I have is:

Boat, Beta 38hp, 2 yrs old, naturally aspirated, kubota block, runs 20-40 hours per year, Scottish West coast, including winter.
Beta recommend
-30 deg to 0 deg ........10W30
-15 deg to 15 deg ......15W40
0 deg to 30 deg ..........15W40
25 deg and over .........15W40

Small tractor: Yanmar 35hp engine, 8 yrs old, naturally aspirated, runs 60-100 hours per year, Cumbria, including some winter use, down to say -5.
Italian manual translated recommends 15W40, nil else mentioned
Yanmar manuals online say
10W below 10 deg C,
20W at 20 deg C,
30 or 40 at 20-35 deg.

Lawnmower, Kubota 21 hp, 3 yrs old, naturally aspirated, runs 40-50hrs per year, mainly summer of course, Cumbria.
Manufacturers recommend
10W30, or 10W40 - the latter if ambient temp >30 deg C.

I hope that I can use 10W40 in all of them, and that a cheaper (mineral?) one may suffice because I am not running for long hours before changes. But, clearly it is a very technical topic - any advice appreciated. (I always try run the engines until warm, and under load by the way - as advised by forumites.).
Click to expand...

I would not use a 10W/40 in either the boat or the tractor, no idea about lawnmowers. 15W/40 is the minimum IMHO. The API grade is the important consideration, can't advise without it but I'm guessing they will recommend an API CD or CF.
 
Never use synthetic oil in old little used diesel engines. A bog standard cheap oil for deisel engines will do the job, synthetic ones are too sofisticated for engines that are not regularly used, ie boat engines.
 
Thank you all, and Vyv - thanks too for all the effort that must have gone into the website.

I have hunted carefully through the owners manuals supplied

Beta: (surprisingly) no mention of the API oil classification - I shall email them.
Tractor: no mention of the API oil classification - online manuals say API CC or API CD
Mower: API CD, CE or CF.

So it sounds like 15W40 to API CD or CF.

Thanks again.
 
vyv_cox said:
I would not use a 10W/40 in either the boat or the tractor, no idea about lawnmowers. 15W/40 is the minimum IMHO...
Click to expand...

I'm curious about the viscosity. Presumably the 10W40 is thinner at typical UK startup temperatures (say -10 to + 25 degrees C) than the 15W40, but would still be thicker than either oil once they were at working temperature? If that's the case, would the lower viscosity oil not be better for all the engines? They never seem short of oil pressure when cold! I have been told that mineral oils that span a large range of viscosities tend to break down sooner, so (say) a 10W40 would last longer than a 10W50. Would that have anything to do with it?

Slightly off-topic, but my (pretty old!) boat engine has a roller bearing crank and no oil pump. It has a conventional shell bearing for the big end and a plain bush for the little end. The big end has a "scoop" on the bottom that dips into the oil at BDC and "scoops" up a bit of oil to go round the bearing. It's supposed to run a straight SAE 30 grade but I've always used a mineral multigrade (10W40) and it sems happy. Just wondering if that might be a bad idea?!
 
Avocet said:
I'm curious about the viscosity. Presumably the 10W40 is thinner at typical UK startup temperatures (say -10 to + 25 degrees C) than the 15W40, but would still be thicker than either oil once they were at working temperature? If that's the case, would the lower viscosity oil not be better for all the engines? They never seem short of oil pressure when cold! I have been told that mineral oils that span a large range of viscosities tend to break down sooner, so (say) a 10W40 would last longer than a 10W50. Would that have anything to do with it?

Slightly off-topic, but my (pretty old!) boat engine has a roller bearing crank and no oil pump. It has a conventional shell bearing for the big end and a plain bush for the little end. The big end has a "scoop" on the bottom that dips into the oil at BDC and "scoops" up a bit of oil to go round the bearing. It's supposed to run a straight SAE 30 grade but I've always used a mineral multigrade (10W40) and it sems happy. Just wondering if that might be a bad idea?!
Click to expand...

10>40 covers the range you require ie 30 grade as does 15>40
 
This might get the tribologists out of hiding.

A 10W 30 and a 10W 40 MIGHT start with the same base oil. The 10W 40 just having a bigger 'dose' of viscosity index improver. Generally the base oil does not break down the VII does along with the corrosion inhibitor, pour point depressant, anti-foamer, demulsifier etc etc.

Similarily the 10W 40 and the 15W 40 MIGHT start with the same base oil. The 10W 40 just having a bigger 'dose' of pour point depressant

As your engines are lightly used and spend long periods cold I would look for an oil with good anti corrosion properties and good anti sludging properties.

If you suspect that your engine OIL has been overheated then it should be changed fairly soon after as the commonly used anti corrosion additive is an organic acid which breaks down at high tenperature.

There was a lot of research done on anti corrosion diesel oil as for a long time diesel fuel had a high sulpher content giving rise to acidic residues.
 
Common engine oil for 3 engines

Just to post Betamarine's reply when asked what API

Question:
"Type Beta B-38 HE
Serial number 7U5880
Can I ask what API spec you advise for the engine oil?"


Reply:
Use 15/40 mineral oil, not turbo or synthetic
If it says AND turbo that will also be fine .
If it says ONLY turbo don’t use it.


I have asked Beta a follow up question checking that implies API CD or CF
 
Avocet said:
I'm curious about the viscosity. Presumably the 10W40 is thinner at typical UK startup temperatures (say -10 to + 25 degrees C) than the 15W40, but would still be thicker than either oil once they were at working temperature? If that's the case, would the lower viscosity oil not be better for all the engines? They never seem short of oil pressure when cold! I have been told that mineral oils that span a large range of viscosities tend to break down sooner, so (say) a 10W40 would last longer than a 10W50. Would that have anything to do with it?
Click to expand...

In theory a 10W/40 and 15W/40 oil would have the same viscosity at working temperature. It's at startup that the viscosity of the former would be lower. Big-end bearing loads are perhaps at their highest at that time, so my opinion is that we need all the viscosity we can manage.

This is another example of how yacht engines have been left behind in the search by the automotive manufacturers for better economy. Oils are becoming thinner and thinner, to reduce friction. If you have handled any of the modern 0W/20 or 5W/20 oils you will share my amazement at how thin they are - shake the bottle and it's just like water! But don't forget that these go in cars that have aluminium/tin or aluminium/lead or even fancier materials for their bearings. The fatigue life of these is typically four times that of the ones in many of our yacht engines. Their compressive strength and wear resistance is similarly in a different league. Use one of those oils in an old Volvo, Yanmar or Bukh, or possibly even a brand new one, and its life would be seriously compromised.
 
vyv_cox said:
Big-end bearing loads are perhaps at their highest at that time, so my opinion is that we need all the viscosity we can manage.

.
Click to expand...

What you need at start up is for the oil to have stayed on the bearings and a good film strength.

This is absolutely NOT the same as viscosity.
A high viscosity may just mean that the oil takes longer to reach parts of the engine.

Also big end loads are related to rpm squared and cylinder pressure, both of which are lower at start up than at high load high revs. No consolation if the oil has left the bearings though.

Cheers,
 
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