Yanmar 2GM20 Oil

[dom]

My 2 litre Ford diesel cruises at 2000 rpm (70mph) on a motorway for hours on end. It is using around 80 bhp (out of 138). This is somewhat similar to cruising with my Volvo in the boat./QUOTE]

My scruffy old Citroën Berlingo cruises the motorway for hours on end at 70mph, using much less than the measly 60hp it has available. I think you are greatly overestimating the power your car uses at that speed. Dammit, I had a 2CV which would cruise at 70 all day on 29hp.

Indeed. My 2l Yanmar whacks out a puny 75bhp at full chat; boat needs c.30bhp to achieve 80% of hull speed in the flat; much more in a chop. I mostly set the throttle and go. My old E320 puts out 220bhp max, but as you say requires only a fraction of this at motorway speed. Multiple cold starts, short runs, endless idling in traffic, and 600-2500rpm work are its life. The son's BMW M4 whacks out an impressive 425bhp form its 3l engine, and it must cope with having the daylights revved out of it on cold mornings for its 1m trip to the golf course. A few ours later, some more hoar's drawers revving, switch off, and that's it for the week :ambivalence:

So the designers don their thinking caps and spec an engine to be a happy companion for each of these owners and the oil bods try to sort out an oil to comply with what the designers want. Fortunes are spent to get the science and engineering right.

The experts may indeed get it wrong sometimes, but criticisms without hard evidence can sound like Harry Enfields, " U don't wanna do it like aah, you wanna do it like ahht !!"

 

[Tranona]

My 2 litre Ford diesel cruises at 2000 rpm (70mph) on a motorway for hours on end. It is using around 80 bhp (out of 138). This is somewhat similar to cruising with my Volvo in the boat./QUOTE]

My scruffy old Citroën Berlingo cruises the motorway for hours on end at 70mph, using much less than the measly 60hp it has available. I think you are greatly overestimating the power your car uses at that speed. Dammit, I had a 2CV which would cruise at 70 all day on 29hp.

But your 2CV only weighs the same as a bag of crisps compared with 1500kgs for my barge!

 

[awol]

But your 2CV only weighs the same as a bag of crisps compared with 1500kgs for my barge!

I believe Newton's 1st Law applies and unless acted upon by an external force, e.g. wind or gravity, the mass of the cars has negligible effect and to a 1st order both need the same power for a 70mph cruise. One may take a little longer to achieve that speed.

 

[PaulRainbow]

I believe Newton's 1st Law applies and unless acted upon by an external force, e.g. wind or gravity, the mass of the cars has negligible effect and to a 1st order both need the same power for a 70mph cruise. One may take a little longer to achieve that speed.

So you can push 2 tons along at 70MPH using the same power as pushing 250kg at 70MPH ?

 

[dom]

So you can push 2 tons along at 70MPH using the same power as pushing 250kg at 70MPH ?

Assuming no efficiency/friction losses in the mechanics, then yes, vehicles with the same aerodynamics can be driven at a constant 70mph using exactly the same power.

 

[JumbleDuck]

But your 2CV only weighs the same as a bag of crisps compared with 1500kgs for my barge!

On the other hand it has the same drag as a Space Shuttle parachute ...

 

[JumbleDuck]

So you can push 2 tons along at 70MPH using the same power as pushing 250kg at 70MPH ?

On the flat the only significant difference is in increased rolling resistance from more deformed tyres, and that is a relatively minor effect. At 70mph, air resistance completely dominates a car's power requirements.

 

[dom]

On the other hand it has the same drag as a Space Shuttle parachute ...

2GM — 2CV — Space Shuttle ...golly, torquey little beasts

 

[PaulRainbow]

This is great news, i'm going to buy myself a large Mercedes estate car and fit a 2CV engine to it, economy will be impressive for such a big car :encouragement: Maybe i can create a market for it

 

[JumbleDuck]

This is great news, i'm going to buy myself a large Mercedes estate car and fit a 2CV engine to it, economy will be impressive for such a big car :encouragement: Maybe i can create a market for it

You won't get terribly good acceleration, but 30hp should be quite enough to cruise a Mercedes estate at 70mph. My old VW camper van weighed 1 1/4 tons empty and cruised very nicely at 70 with its 50hp engine and laughing contempt for the concept of "streamlining". It would easily do 60 (legal limit) with 3/4 ton of glider plus trailer behind.

 

[coaster63]

This is great news, i'm going to buy myself a large Mercedes estate car and fit a 2CV engine to it, economy will be impressive for such a big car :encouragement: Maybe i can create a market for it

Volkswagon group have beaten you to it (cylinder deactivation) for cruising ! so will you go for the Bentley Continental

 

[PaulRainbow]

Volkswagon group have beaten you to it (cylinder deactivation) for cruising ! so will you go for the Bentley Continental

I think i might, especially if i can deactivate one of the 2CV cylinders. Economy will be really great if i can deactivate two cylinders and maintain 70MPH

 

[lw395]

My 2 litre Ford diesel cruises at 2000 rpm (70mph) on a motorway for hours on end. It is using around 80 bhp (out of 138). This is somewhat similar to cruising with my Volvo in the boat.......

My car does about 50 to 55 mpg if you can cruise at a constant 70mph
That's about 1.33 GPH
Diesel efficiency is around 0.25 litres per HP per hour, so I reckon my car is using about 25 of its 160 HP.
If I change into 3rd and floor it up a hill at 70, I cant get the indicated MPG down to a pretty low number.

I'm not really sure what point you were trying to make, but your premise is wrong, unless you were talking about a Luton van or similar aerodynamic disaster?

 

[MonniotC]

It requires a specific amount of power to be generated (say 30BHP) to cruise a mercedes Estate at 70 MPH. To generate that specific amount of power, a specific amount of fuel must be consumed, mostly to overcome wind resistance, as has been said. Assuming that the 2CV engine and the Mercedes engines are more or less equally efficient at converting heat into motion, then it will make no difference to the fuel consumption at a steady speed on the flat whichever engine is under the bonnet.

 

[Steve_N]

My 2 litre Ford diesel cruises at 2000 rpm (70mph)

My 2 litre VAG (SEAT) diesel must be over-propped - 70mph is at 1600rpm

 

[RichardS]

We read your claim every time this subject comes up and you never actually say what this "OBVIOUS" benefit is. Surely if it was obvious you could state what it is and provide evidence to support your claim? Instead you go off topic and talk about high powered road car engines.

It is only you that claims synthetic oil has a benefit for "any internal combustion engine". I find this surprising as all the major oil companies disagree - we have 2 examples on this thread, each giving a considered explanation for their position.

So your failure to explain yourself and convince others seems to be because you don't have an explanation, never mind evidence.

Good grief .... I explained all this much earlier on in this thread and in every other thread about mineral v synthetic I've participated in. However, I'll do a copy and paste from this thread: As you know, I've never found any harm being created in older engines by using semi or fully synthetic but have always been amazed by how clean and carbon-free the engine remains internally and that's enough to weigh the analysis over to the benefit side for me

Now, please can we leave it because I'm fed up repeating the same stuff over and over.

Richard

 

[Tranona]

Good grief .... I explained all this much earlier on in this thread and in every other thread about mineral v synthetic I've participated in. However, I'll do a copy and paste from this thread: As you know, I've never found any harm being created in older engines by using semi or fully synthetic but have always been amazed by how clean and carbon-free the engine remains internally and that's enough to weigh the analysis over to the benefit side for me

Now, please can we leave it because I'm fed up repeating the same stuff over and over.

Richard

Of course we can leave it - but what you post is meaningless. Have you stripped your Yanmars and another pair having done the same hours but on the recommended oil. Were yours cleaner?

Why does it matter that the engine is cleaner? and why doe sit matter that no harm is done? when no harm is done using the correct oil.

I am just amazed that all you can show as a benefit is that your road car engines are clean after using synthetic oil. Hardly rigorous scientific analysis is it? Just repeating something as meaningless as this is hardly convincing.

 

[RichardS]

Of course we can leave it - but what you post is meaningless. Have you stripped your Yanmars and another pair having done the same hours but on the recommended oil. Were yours cleaner?

Why does it matter that the engine is cleaner? and why doe sit matter that no harm is done? when no harm is done using the correct oil.

I am just amazed that all you can show as a benefit is that your road car engines are clean after using synthetic oil. Hardly rigorous scientific analysis is it? Just repeating something as meaningless as this is hardly convincing.

"Rigorous scientific analysis" ..... are you being serious Tranona? This forum, and all other forums, is about experience and opinion.

If you want "rigorous scientific analysis" you can try the oil manufacturer or the engine manufacturer. The oil manufacturer will say "We don't know, ask the engine manufacturer" and the engine manufacturer will say "We haven't tested our engine with the type of oil you are suggesting". Both of these responses mean that synthetic oil might be really bad or might be really good or might make no difference ..... which is where experience and opinion comes into it.

Richard

 

[ghostlymoron]

Who'd have thought such a simple question could elicit such complicated answers. Talk about bore glazing - my eyes were glazing! BTW what's the DS that was referred to?
I use mineral to API CD 5-40.

 

[dom]

"Rigorous scientific analysis" ..... are you being serious Tranona? This forum, and all other forums, is about experience and opinion.

If you want "rigorous scientific analysis" you can try the oil manufacturer or the engine manufacturer. The oil manufacturer will say "We don't know, ask the engine manufacturer" and the engine manufacturer will say "We haven't tested our engine with the type of oil you are suggesting". Both of these responses mean that synthetic oil might be really bad or might be really good or might make no difference ..... which is where experience and opinion comes into it.

Richard

No problem not having evidence. But why misrepresent the position of BP and Yanmar like that? And and as far as I know the position of other oil majors and engine OEMs.

Both emphasise that yacht auxiliaries have different and intermittent usage patterns, operate in different climates, with different fuels, different duty cycles, etc. They go to great lengths to manufacture engines with simple service schedules to keep them fit for long and happy lives. Where a specific oil grade is superseded they will specify a backwardly compatible one.

Assisted by their massive R&D budgets, this process by and large works great.

You are of course free to beat your own path, but it carries risks -- risks 99% of people would not take without the blessing of a major oil co. or engine OEMs. Horses for courses.