what is an acceptable level of oil usage?

[fjgvdo]

I am sailing a 45ft sloop equipped with a Volvo MD22-P (59HP) engine. The engine fires up immediately on pressing the starter button and runs very well. It has approx 1300hrs on the clock. I use the recommended Volvo engine oil. The engine uses 1L per 40-50 hours. Is this regarded unacceptably high?
Would anyone have recommendations for alternative engine oils with different viscosities and/or engine oil additives?

[S/V Illusion]

That's not atypical although less would be preferable. If you are concerned, rather than play with additivies or different viscosities, both of which would only mask the cause and likely not solve anything, why not check the compression, rings, etc to see where and how the oil is being burned or lost?
Adding stuff only hides the cause, not fixes it.

[Rick]

Wouldn't expect any noticeable oil usage until after 100 hrs on a change with only 1200 hrs on the engine. Like Illusion implies, something is wrong.

[Joli]

If its blue on start up its going down the valve seals. If not then its blow by past the rings. I would not worry much a bout a liter per 50 hours. Pat?

[never monday]

I was giving it a few min.

MD22 is a few years old. produced from 1988-2002.
This would lead me to think seals and weak rings. BUT, it fires on the first revolution, this statement is not indicative of weak rings. So, back to seals.
What kind, color, and volume of some is it making?
Can it rev to it's full speed? again what kind of smoke while running?
Is there oil in the air filter/intake tract?
The oil you are using, what weight is it? is it the synthetic?
Where are you on this planet? you climate can be a factor.

oh, yes I would consider a L/50hrs high

[Alan Wheeler]

Many theories because there can be many reasons.
Firstly, don't go by the colour of the smoke on initial startup. The blue smoke you often commonly see is usually cold fuel oil sitting in the dry areas of the exhaust and cyclinders etc. Continued smoking is more of a sign of possible wear issues.
1300hrs is not a lot and I would think the issue maybe more in how the engine has been looked after. Read the Study hall as to how to start and warm up the engine. I would also suggest you make sure the engine has had a good hard run. Often these engines don't get such a luxury. They have to be worked hard once in awhile or they will burn oil.
DO NOT use additives. Ensure you have the correct grade of oil for your climate, mainly that it is not too low a viscosity in a hot climate, or the oil will be too thin. A good quality mono grade 30W oil is of good choice. Mono grades remain more stable. Multigrades can cause an issue. Read the oil pack and see what the Volvo oil grade actually is. You certainly won't be doing any harm by buying another brand as long as it is a good grade. That means the performance standards it has to meet usually written near the bottom of the label.

[Sandero]

I know absolutely nothing about diesel engines. I have a Volvo MD17D in Shiva for 22 years.

Last year I had to re build the valves, and did the whole top end so to speak, but not the rings.

The engine fires up when warm very quickly and not quickly when cold. It does toss out a lot of grey smoke when cold which clears up as the engine gets up to operating temp. When starting warm there is no smoke.

I believe that the smoke is from unburned remaining fuel in the cylinder which is not well combusted.

I do have a little bit of smoke all the time and I suspect my rings are worn, but the compression test was OK so I live with it. I see a bit of oil slick in the exhaust water which looks like rings to me. But what do I know.

I change oil every 50 or so hours and often the level is down perhaps half a quart, but I never can get the rated amount out with a pump at a fuel change and of course the filter is filled too.

My engine has more than 4,000 hrs with a lot put on when I lived aboard cruising for 4 yrs. I'm satisfied and expect to die before the engine does.

[Elie]

I also own a version of this engine , that is fact a very modern Perkins diesel engine found initial a gas engine (Bedford trucks) converted and modernized for diesel. and very commonly used in many Austin, Rover Montego, Morris, etc, in production until 1996 I believe. Other versions exist like the Volvo Md22L, LA, P, TD, and even a series 500 Perkins name. But it is essentially the same engine sharing all the internal parts, with differents injections pumps, injectors, alternators and staters, and the paint colors. It has a overhead camshaft driven by a 'rubber' cam belt quite unusual for marine diesel engines. The marine version of this engine do not have all the nice starting devices found on the car version, and therefore, may smoke a bit at start up when cold. What I found is that most of that smoking is related to fuel injection system, and warm up procedure. All smoke vanishes after a minute or so. My smokes grayish blue of gray-white depending on temperature. But it also starts immediately, and never burns any significant oil. The compression ratio around 17.5 is quite low and that may be part of this bit of smoking at startup. I would not worry about such low oil burning. This may have to do with the valve seals. I would recomand to check the timing belt, its failure would be catastrophic, and if you decide to have it replaced, you may as well have the valves checked and the seal replaced while at it. but mostly, I would say: all's fine! Find something else to worry about!

[fjgvdo]

Thank you very much for your responses.

We sail in The Channel and N France/Britanny, hence not the hot climes of Florida. The oil used in the negine is Volvo's regular 15W-40; one issue that may have influenced things this past season is that the prop pitch of the MaxProp was slightly too high which meant that the engine would not rev up to its design revs. Would this elevate oil use??


Frans
SY Belladonna

[S/V Illusion]

Not in my experience Frans. We have a Maxprop on a 52 HP Yanmar 4JH and intentionally over-pitched the prop for reasons not relevent to this discussion and have not noticed any adverse effects. We do, however, never run at max rpm because of the pitch but then again, never need to exceed 80% of max.

[Alan Wheeler]

Ummm yes it can. It is also very bad for the wrist pins and big end bearings. Plus you get the wrong type of wear in the cylinder as unburn't fuel washes down the sides of the bore and can cause scoring. Scoring is bad.
You MUST and I emphasis again the MUST match your engine to the prop. The engine has to be able to reach full RPM under laod. If it can't, you will eventually run into problems and those problems will be sooner than later and severe. Unless you have a stupidly over sized engine Hp for the boat, you will never be operating in any decent power area of the engine. The boat may feel like it is performing OK, but there will be much more it can deliver if it can rev to what it is supposed to.
Let me give you an example. (becuase I have the graph sitting in front of me already, I will give you the ratings of the Perkins 6.354)
This engine is sold as a 129Hp engine, which is an SAE rating. In reality it is far from it and many different manufacturers use or at least used to use the SAE rating.
I will use Shaft Hp and the continuous rating.
@idle 750RPM=~40 SHP
@1500=~65 SHP
@1700=~75 SHP
@2000=~82 SHP
@2250=~90 SHP
@2400=~95 SHP
Max intermitent is 2800RPM and 115 SHP.
So you can see that if you can only achieve 1800RPM for say, you are somewhat down the scale in the available Hp. So the boat will never handle the same as it would if the engine was at full RPM. Full RPM does two things. It gives you max Hp as I have just shown, but it also gives the prop greater efficiency in the water. The faster the prop spins, the less slip it has.

[David M]

Check the manufacturers specifications for oil consumption for your engine. Engines all vary in their consumption. Even the same engine coming off the same assembly line on the same day can vary in their consumption. There is no such thing as "Normal". There is a maximum allowable which is determined by the manufacturer. Manufacturers are pretty generous with this number so they can get away with minor manufacturing imperfections.

[MidLandOne]

I have a MD22L which is basically the same engine. We find that the oil usage depends - what it depends on I haven't figured out but I have spoken with a number of others around the world with MD22L's and they all find the same. The MD22L is a non turbo and slow revving engine (for its size) at 2,700-3,000rpm. If I have it correct I think yours is the turbo version and also a later model of the same basic engine (the turbo of the same vintage as ours engine is the TMD22, with I think the MD22P being a later nomenclature for a similar engine).

I think some of it depends on the turbulance and in bouncy conditions with a lot of splashing around or hard running into gale conditions it is not unusual for us to use 1/4 litre in 6 hours running. This seems to fit in with what others have told me with the same engine.

We are currently away cruising so have done a check for this post - best I can estimate from engine hours when we left and oil put in since we seemed to have used roughly 0.4 litre in around 35 hours of mixed running (cruising and charging). Around half that was burnt in around 6-1/2 hours, half of which was pushing hard in quite jobbly tidal race conditions (no wind)

The comments already made on light smoking when starting etc all are so with our engine. It'll run blue smoke for a couple of minutes when first pushing the boat after previous hours being just charging (for the reasons Alan gave).

When our boat was new the engine supplier at the first service (25 hours I think) put a synthetic oil in and the engine started smoking a lot. I replaced it with a mineral multigrade and it was fine and then later had a lengthy discussion with the technical people at my favourite oil company about that and about the oil consumption in general. Their recommendation for the engine was to just use whatever the current range of multigrade non synthetic oil was on the shelves targeted at diesel automobiles from a major oil company. They did not think our oil usage was any real issue even for a newish engine.

I replaced the timing belt at around 725 hours (much longer than recommended in the manual but took it out that long on advice, plus I checked the belt regularly - it is a burden to replace for us as there is auxiliary equipment mounted on the front of the engine which all has to come off). When I did so I found that the crank/cam/fuel timing had been out from new and after I set it all up the engine ran very noticably quieter, very much so on idle. I think that after that it is actually using less oil. When replacing the timing belt it pays to replace the belt idler and adjuster pulleys as well (they are expensive) - I didn't as they are heavy duty nicely made items and I thought they would be fine, but had to replace them shortly after as one got noisy. The local Volvo guy who gives very straight advice said he always replaced them with the belt.

As I said, everyone with the MD22L that I have spoken to has found the same regarding oil consumption. I suspect the others in the family, such as yours, are likely the same. I would just stick with a multigrade (with no additives as others have said) and not worry about it myself unless it gets to the stage where you can't pour oil in faster than it burns it, you look like a destroyer laying down a smoke screen, or there is something obviously wrong with the engine.

[Ex-Calif]

Higher RPMs can result in higher oil consumptionfor the same engine. It's simply a function of revolutions and the volume of oil you are flowing (higher at higher rpm).

Oil disappears for two reasons - consumption or leakage. If it is not leaking, it is being consumed by the combustion process. There is no easy fix to consumption.

The best medicine is to accurately log consumption vs. rpm over time. Make sure you keep it above the low level and carry on. Consumption can be an indication of other issues - valve seals and piston ring/cylinder wall deterioration. By itself oil consumption will not indicate an inreliable engine and an engine consuming oil can likely go on for years in light boat service.

Wheels always gives good counsel and it bears repeating. The best thing you can do for your diesel marine engine is run it hard. Firing it up, running it 10 minutes at low rpm to get into the channel to raise sails is not friendly to the engine. It needs to get up to temperature and be "rode hard" to seat rings and all sorts of other reasons.

We often use our engine as above for the 10 minutes in and out of the mooring but frequently we will leave the engine running at full speed under sail for 30 minutes or so to top the batteries and give the engine a work out.

Try running it hard for 10 hours or so and see if the consumption changes.

[Elie]

This Volvo-Perkins engine is used mostly as a car engine, on Austin Montego and Land Rovers. I just can't believe that drivers of these cars has to drive their machines at the speed required to drive hard their diesels on British roads where speed limits exist. And beside, the same engine is given at different powers depending on the max rev the engine is set. The rev varies from 3000 to 4500 rpm. Taking into account that all major parts are identical(cam shaft, head, oil pump, crankshaft) from an engine to another(exempt for turbo where pistons, oils passages, and a few little things differs). How can essentially the same engine with different top rpm shall be run efficiently to insure durability?. Why is it different for marine engine than for car engines, diesel or not diesel?. In Europe 80% of new cars are diesel equiped. Are they required to run close to top rpm?. I rented a diesel Peugeot car on my last trip in France. The car tickled nicely at interstate speeds, far from the top rpm. Will all these car diesel engine die in early age? How come marine diesel engines has to be different?.