Volvo MD 22 fuel consumption

Bobc said:
It is a car engine which revs to 4300rpm.

Recommended cruising revs is 3,000 - 3,300, although that's a bit much, but at least 2,500.

Run it at 2,000rpm and it's not getting up to full working temperature.
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Thanks for that but I can assure you mine up to full running temperature,
I can only speak for myself here and no one else if I run mine at them speed I probably blow some thing especially in the heat of the Med .
I can see why people are saying 3 LPH if they running at them REV .
 
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It might be based on a car engine but our Perkins M50 won't do more than about 2600 out of gear. It's a marine engine that's very conservatively rated. I'm happy about that as, hopefully, it will go on for ever!
 
As for not getting up to working temperature at 2000 revs, that's just ridiculous. We came through the French canals and hardly ever exceeded 1100 rpm because of the speed limit. The engine temp was just fine.
 
Cruising speed
Operating the engine at wide open throttle (WOT) should be avoided since it is both uneconomical and uncomfortable. Volvo Penta recommends a cruising speed in the range 300 - 500 rpm lower than maximum rpm at WOT. Depending on hull type, choice of propeller, load and conditions etc. the maximum engine speed at top speed can vary, but it should be within the WOT range......

There recommendion are set to work with there three fixed blade propeller or their two blade folded ,
once you start changing stuff the recommendations goes out of the window ,
Then you have to take all the other stuff in consideration, and again it just a recommendation.
By the way the MD 22 isn't a Volvo engine .
 
Hoolie said:
It might be based on a car engine but our Perkins M50 won't do more than about 2600 out of gear. It's a marine engine that's very conservatively rated. I'm happy about that as, hopefully, it will go on for ever!
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If it only revs to 2600 out of gear, there is something wrong with your engine.
 
sailaboutvic said:
Cruising speed
Operating the engine at wide open throttle (WOT) should be avoided since it is both uneconomical and uncomfortable. Volvo Penta recommends a cruising speed in the range 300 - 500 rpm lower than maximum rpm at WOT. Depending on hull type, choice of propeller, load and conditions etc. the maximum engine speed at top speed can vary, but it should be within the WOT range......

There recommendion are set to work with there three fixed blade propeller or their two blade folded ,
once you start changing stuff the recommendations goes out of the window ,
Then you have to take all the other stuff in consideration, and again it just a recommendation.
By the way the MD 22 isn't a Volvo engine .
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You should cruise a diesel at about 2/3 to 3/4 of it's rated rpm. Diesels need to run hot.
 
Bobc said:
You should cruise a diesel at about 2/3 to 3/4 of it's rated rpm. Diesels need to run hot.
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Bob, not wishing to get in to a pissin contest :) but a diesel engine can be flat out at less than rated full revs. Put a heavy load on it by over propping a bit for example can in theory make the governor open the rack fully to keep the revs at the throttle indicated range.
My prop is a 16 by 16 three bladed one, allegedly not standard Beneteau, allegedly over size. It gives me 6 -7 kts at 2100 rpm. If I go to full throttle it will rev to about 3200 BUT the speed doesnt go much better, the stern squats and serious black smoke is emitted. So my engine is loaded at 2100, up to temperature and yet is economical
 
Heckler said:
Bob, not wishing to get in to a pissin contest :) but a diesel engine can be flat out at less than rated full revs. Put a heavy load on it by over propping a bit for example can in theory make the governor open the rack fully to keep the revs at the throttle indicated range.
My prop is a 16 by 16 three bladed one, allegedly not standard Beneteau, allegedly over size. It gives me 6 -7 kts at 2100 rpm. If I go to full throttle it will rev to about 3200 BUT the speed doesnt go much better, the stern squats and serious black smoke is emitted. So my engine is loaded at 2100, up to temperature and yet is economical
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For sure you can always over-prop an engine, but that's as bad as under-driving it. You just end up with a badly coked-up engine and injectors and an over-stressed gearbox.

Frankly I don't care what you all do with your engines, I was simply answering the question about fuel consumption, which when run at the proper cruising revs of about 2600, should be about 3l/hr, and pointing out that that particular engine should be run at more than 2000rpm as it is a low-compression, high-revving car engine. That is all.
 
MD22L-B (50 HP - not to be confused with the 59 HP MD22P!) in a Bavaria 40 Ocean (~12t total weight with all our cruising kit) with Saildrive 120S-E and 3-bladed Volvo fixed prop (17x15).

We mostly cruise at 1800 rpm giving 6.5 knots and using a bit under 3L/h (probably less, but don't have a better figure). With more throttle the engine easily gets us to our hull speed of 8.0 knots, but that would be wasteful.

As this is a bit low rpm for that engine, we throttle it up to full every once in a while (say once per hour or so, although we miss some) at which point some (grey) smoke (not steam) comes out, burning off whatever deposits it built and after 10-30 seconds (depending on how long since the last time) it stops smoking and does not smoke again until ran at lower rpm for a while, clearly indicating something is being deposited at low rpm and burnt off at higher. Might be carbon deposits in the cylinders or on the piston heads or might be something in the exhaust, don't really know.

We've also ran it at full throttle for about 6 hours once fighting our way upwind in a Gale and doing a mere 3-4 knots at that, from bashing upwind in big waves and having to turn the boat to cut over the wave at every single one.
 
How do you all measure your fuel consumptions, bearing in mind that roughly half the diesel drawn from a tank returns to it?

This seems pretty good:
sailaboutvic said:
Our 42 foot MD 22P 1800rpm 2lph 2000 rpm 2.5 LPH
I keep a very close eye on this , my filler is in the cockpit floor , so I tend to fill to the top of the filler then next time do the same and compare with engine hours .
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:encouragement:
 
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Bobc said:
It is a car engine which revs to 4300rpm.

Recommended cruising revs is 3,000 - 3,300, although that's a bit much, but at least 2,500.

Run it at 2,000rpm and it's not getting up to full working temperature.
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That's cobblers.
My car engine runs to 4500rpm.
It spends a lot of its time cruising at 1500 to 1800rpm.
So far 170k miles and no problems.
 
A1Sailor said:
How do you all measure your fuel consumptions, bearing in mind that roughly half the diesel drawn from a tank returns to it?

This seems pretty good:

:encouragement:
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In my case it's petty accurate I would say , my filler is in the cockpit floor , I record engine hours and gen hours , each time I fill with fuel and top right up to about a few ins from the top of the filler .
 
sailaboutvic said:
In my case it's petty accurate I would say , my filler is in the cockpit floor , I record engine hours and gen hours , each time I fill with fuel and top right up to about a few ins from the top of the filler .
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I was nearly caught out a number of years ago when running my engine from an emergency can of diesel as a "get you home" measure with a blocked tank output pipe.
20litres seemed like lots for ~20miles with my BetaMarine ~33hp/Moody336 - but the can seemed awfully light about halfway home.:confused:

I realised some fuel was "returning" to the tank - as I was putting the sails up!
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A1Sailor said:
I was nearly caught out a number of years ago when running my engine from an emergency can of diesel as a "get you home" measure with a blocked tank output pipe.
20litres seemed like lots for ~20miles with my BetaMarine ~33hp/Moody336 - but the can seemed awfully light about halfway home.:confused:

I realised some fuel was "returning" to the tank - as I was putting the sails up!
icon3.png
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I had a 336 quite a lot of years ago Lovely sailing boat .
 
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