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Old 25-03-2014, 08:29   #16
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Re: Yanmar Questions

"can we say it is a trade-off, ie, less efficient while motoring but more efficient under sail?"

Hmmm, that's a good question! From the little I've been able to test and see for now it's hard to say. I'd dare to say there's little to no difference between the Max and the Autoprop under sail.

Other owners of the Autoprop ( yes I know, in the www... ) say that the results under sail are equivalent to the Maxprop.
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Old 25-03-2014, 09:42   #17
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Re: Yanmar Questions

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Originally Posted by Loredo View Post
Try to use a synthetic oil in a Perkins 4.108 and see how that goes. It'll start to burn oil at the same rate of diesel. Well kinda, been there done that and changed back to dyno oil after 20 hours or so. The tollerances... the thin syntethic oil just does not match the old engine design.
Synthetic oil can destroy a marine engine. Read why here:

Oil for yacht engines

The demands and requirements for marine engines, especially auxiliary engines in sailboats, is very different from those of car engines. What is great for a car engine can kill a marine engine.
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Old 25-03-2014, 09:51   #18
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Re: Yanmar Questions

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Originally Posted by Loredo View Post
"can we say it is a trade-off, ie, less efficient while motoring but more efficient under sail?"

Hmmm, that's a good question! From the little I've been able to test and see for now it's hard to say. I'd dare to say there's little to no difference between the Max and the Autoprop under sail.

Other owners of the Autoprop ( yes I know, in the www... ) say that the results under sail are equivalent to the Maxprop.
Testing proves that the Autoprop is less efficient when sailing than the Maxprop. The Autoprop, inherent in its design, droops one blade while feathered, which creates some drag. The Maxprop is definitely sleeker when feathered.

So there is of course a tradeoff. But the increase in drag from the Autoprop is probably not relevant on most cruising boats (might be on a racing boat). For me it's not even noticeable. The improvement in motoring performance from the Autoprop, on the other hand, is dramatic; amazing. So I am happy to have an Autoprop, since like most cruisers I do a fair amount of motoring.

As others have reported, I can reach and exceed hull speed on my boat with the Autoprop (I can get about 10 knots in glassy smooth water with a slight tailwind), and moderate cruising speeds (7.5 - 8 knots) are reached at relaxed RPMs. Self-pitching means you adjust RPM for load, not speed, and it is surely beneficial to the engine that the prop pitches up to keep a constant load on the engine. But best of all is motor-sailing -- with extra drive from the sails, the Autoprop pitches right up and allows you to throttle right down. It is truly delightful sailing at 8 knots in 10 knots of wind with the engine giving a bit of a push while lazing along at 1600 RPM and almost inaudible.

Maintenance of the Autoprop is a slight pain, and the horribly designed anodes are a pain and a non-trivial expense. But these are just about the only noticeable drawbacks, from my experience, at least for a cruising boat where the bit of extra drag is not an issue.
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Old 25-03-2014, 17:05   #19
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Re: Yanmar Questions

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How about the synthetics?

I have been putting the same Mobil 1 Synthetic 0w-40 from my Mercedes diesel into even my small Honda engine with great results. Quiets the engine right down and has much longer service intervals.
Oh, sure - lemme see at $7/qt and I need two barrels (184 gals) - makes perfect sense - NOT!!!
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Old 25-03-2014, 17:23   #20
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Re: Yanmar Questions

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Synthetic oil can destroy a marine engine. What is great for a car engine can kill a marine engine.
You and I will disagree on that matter. Don't scare people with unfounded rhetoric. I've torn down hundreds of diesel engines. None of them had bad pistons, lifters, rings or too much of one metal and not enuf of another due to use of synthetic oils. For high revolution marine (turbo) engines the synthetic oil is perfect. For low rev (n/a) it's a bad choice.
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Old 25-03-2014, 17:24   #21
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Re: Yanmar Questions

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Phoenician,
I always fill up to the neck so that I can see the fuel in the hose. Then I
keep a very close eye on the Rpm's kept and the engine hours. You know, cruising in the summer in the Med one has to motor very often if he want's to get anywhere. On the next fill up I do the math. That's how I get my fuel consumption. Do that time after time after time and see the trend.

Oh, yeah, before I take the boat to any lengthy motoring, I always dive and clean the prop and hull. Any growth on the prop / hull substracts a lot of speed and increases the fuel consumption BIG time.

This is my third boat with a Maxprop. I always felt that the efficeny of that prop is a bit limited. What I mean to say is then closer one get's to hull speed then less efficient that prop becomes. In fact, I've NEVER been able to get any of the boats to the expected hull speed with a Maxprop.



That's one reason I mentioned the speed with the Autoprop. The 8.7K max speed I've seen thus far places me right at the hull speed for the LWL 42'.3". To boot, I got to that speed @ 2500 Rpm.
With the Maxprop, no matter how hard I'd beat on the engine 8.2K @ 2900 Rpm has been the highest speed ever recorded. Anything above 2900 would only increase the noise and the fuel consumption.

I'm not saying that a Autoprop is the solution for everything. In fact for me the overall verdict is still out since I've been able to test it only a couple hours thus far. From the little I've seen it sure looks promising. I'll know more and better by the end of this year...

Engine oil.
One needs to realise that the tecnology in building engines have changed dramatically over the past 50 years. Tollerances have become smaller and steel / bearings quality has gone up.
Try to use a synthetic oil in a Perkins 4.108 and see how that goes. It'll start to burn oil at the same rate of diesel. Well kinda, been there done that and changed back to dyno oil after 20 hours or so. The tollerances... the thin syntethic oil just does not match the old engine design.

At the same pace, use too viscous of an oil in a more modern engine design and you're getting likely the opposite result. Especially with a cold "tight tollerance" engine can that thicker oil get to where it has to go???
Try it and report back! No matter what people say, I'm not going to do that kind of test.
But isn't 0w-40 just the same as 40w once your Perkins 4-108 gets up to speed?
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Old 25-03-2014, 17:28   #22
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Re: Yanmar Questions

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You and I will disagree on that matter. Don't scare people with unfounded rhetoric. I've torn down hundreds of diesel engines. None on account of using synthetic oils. For high revolution marine engines the synthetic oil is perfect. For low rev it's a bad choice.
Agreed. Adding to this, many marine engines are babied compared to a car. You redline cars. You idle in traffic. You make short drives redlining with a cold engine. My Mercedes diesel is also a turbo, which adds other strains.

Moat typical small boat Yanmars have a life of luxury in comparison. They get set at 3200 RPM and left alone. Luxury.
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Old 25-03-2014, 17:43   #23
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Re: Yanmar Questions

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Originally Posted by reefhunter View Post
You and I will disagree on that matter. Don't scare people with unfounded rhetoric. I've torn down hundreds of diesel engines. None on account of using synthetic oils. For high revolution marine engines the synthetic oil is perfect. For low rev it's a bad choice.

By bad choice maybe you mean a waste of money as it's not needed? Or as you saying it will do harm?

People have been berating synthetic oils since the 1970's at least. Many experts have been telling stories about how your rings won't seat etc. with Syn oils. All of it has turned out to be untrue
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Old 25-03-2014, 17:50   #24
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Re: Yanmar Questions

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Originally Posted by oceannavigator View Post
Agreed. Adding to this, many marine engines are babied compared to a car. You redline cars. You idle in traffic. You make short drives redlining with a cold engine. My Mercedes diesel is also a turbo, which adds other strains.



Moat typical small boat Yanmars have a life of luxury in comparison. They get set at 3200 RPM and left alone. Luxury.

Very few if any engines ever get run continuously as high as 3200 RPM other than a boat. Only two engines I know of get run hard continuously are boats and airplanes. RPM isn't really a good indicator as percent of power, but unless your on the Autobahn your not puling even 50% power from a car engine, sustained.
Now you guy's may not run your engines hard, but plenty of boat owners do, and I think your running them harder than you think. For instance the 3200 RPM example if the engine governed RPM is 3600, then your running it at 88% of max. Take a typical car whose redline is 6,000 RPM
88% of 6,000 is 5280 RPM, who continuously runs their car that hard for hours?
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Old 25-03-2014, 18:25   #25
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Re: Yanmar Questions

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Very few if any engines ever get run continuously as high as 3200 RPM other than a boat. Only two engines I know of get run hard continuously are boats and airplanes. RPM isn't really a good indicator as percent of power, but unless your on the Autobahn your not puling even 50% power from a car engine, sustained.
Now you guy's may not run your engines hard, but plenty of boat owners do, and I think your running them harder than you think. For instance the 3200 RPM example if the engine governed RPM is 3600, then your running it at 88% of max. Take a typical car whose redline is 6,000 RPM
88% of 6,000 is 5280 RPM, who continuously runs their car that hard for hours?

Uh... my Mercedes turbo diesel would explode!!! lol

Are you talking about gasoline engines? If so, no need. They have nothing to do with diesels and you can't compare them. All points you are making are valid for gasoline engines. Apples and oranges.

I'm talking apples to apples. My Mercedes turbo diesel spins at 2800 RPM doing 70 MPH.

It's working exactly the same as my Yanmars did, for 24 hours straight when going from the northeast usa to Miami.

A marine diesel and a highway diesel are the exact same thing. Betra marine? Nanni diesel? Etc? Zero difference.

However, the road diesels get beat on by long idling periods, high rpms when cold, etc. Either case, the good Mobil 1 is superior in all ways to others. Marine or highway. Of course, you want to keep warranties valid and use what the manufacturer suggests, but the improvement in mileage, fuel efficiency and quieting of the engine is astonishing with Mobil 1. I use it in my Honda generator and it's unbelievable. Ran it every day, 12- 14 hours a day, all summer long. Still strong as ever. And quiet... using less fuel. The stuff is amazing.
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Old 25-03-2014, 18:43   #26
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Re: Yanmar Questions

Quote:
Originally Posted by reefhunter View Post
You and I will disagree on that matter. Don't scare people with unfounded rhetoric. I've torn down hundreds of diesel engines. None of them had bad pistons, lifters, rings or too much of one metal and not enuf of another due to use of synthetic oils. For high revolution marine (turbo) engines the synthetic oil is perfect. For low rev (n/a) it's a bad choice.
This is what a professional lubricant engineer says about it:

"Yacht auxiliary engines generally run for short periods, at lower temperatures than any other duty, and typically in the lower half of their rev range. From a lubricant point of view this is a very undemanding duty, accounting for their low API requirement. Combustion temperatures never reach levels at which a high-performance lubricant can be effective, so the overall chemistry in this area is not neutral but alkaline (basic). There is a great deal of evidence to show that use of an oil with a TBN that is too high for the duty can lead to several problems, particularly high wear rates of cylinder bores. The effect of high TBN engine oils in accelerating wear rates is well known. Burning high TBN oils may generate excessive deposits on the piston crown. As the piston tilts when moving up and down these deposits become compressed and will form a very hard and abrasive layer, causing excessive wear, mainly in the bore.
"Bore wear has similar detrimental effects as bore glazing, instead of a smooth glaze producing a highly polished surface that leads to poor lubrication and high oil consumption."


http://coxengineering.sharepoint.com/Pages/Oilforyachtengines.aspx


API grade CD oil specified by Yanmar, has initial TBN of 4. Initial TBN of Mobil One is 15.5.


Synthetic oil is great for hot-running terrestrial engines where oil temp gets up to 120C and higher -- and that's what synthetic oil is made for -- to keep its film strength at high temperatures and pressures. It is completely inappropriate for yacht engines where the oil is cooled by seawater and will not even reach the operating temp of the engine. Synthetic oil was simply not made for this duty.


Yanmar even say that use of synthetic oil in their engines will void the warranty.
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Old 25-03-2014, 19:01   #27
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Amen to that brother.
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Old 25-03-2014, 19:27   #28
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Re: Yanmar Questions

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This is what a professional lubricant engineer says about it:

"Yacht auxiliary engines generally run for short periods, at lower temperatures than any other duty, and typically in the lower half of their rev range. From a lubricant point of view this is a very undemanding duty, accounting for their low API requirement. Combustion temperatures never reach levels at which a high-performance lubricant can be effective, so the overall chemistry in this area is not neutral but alkaline (basic). There is a great deal of evidence to show that use of an oil with a TBN that is too high for the duty can lead to several problems, particularly high wear rates of cylinder bores. The effect of high TBN engine oils in accelerating wear rates is well known. Burning high TBN oils may generate excessive deposits on the piston crown. As the piston tilts when moving up and down these deposits become compressed and will form a very hard and abrasive layer, causing excessive wear, mainly in the bore.
"Bore wear has similar detrimental effects as bore glazing, instead of a smooth glaze producing a highly polished surface that leads to poor lubrication and high oil consumption."


http://coxengineering.sharepoint.com/Pages/Oilforyachtengines.aspx


API grade CD oil specified by Yanmar, has initial TBN of 4. Initial TBN of Mobil One is 15.5.


Synthetic oil is great for hot-running terrestrial engines where oil temp gets up to 120C and higher -- and that's what synthetic oil is made for -- to keep its film strength at high temperatures and pressures. It is completely inappropriate for yacht engines where the oil is cooled by seawater and will not even reach the operating temp of the engine. Synthetic oil was simply not made for this duty.


Yanmar even say that use of synthetic oil in their engines will void the warranty.
Aside from the gasoline engine distinction, it looks like we have another distinction that is needed to have this conversation.

A64 pilot's argument as to why we cannot use synthetics like Mobil 1 is that marine engines are worked very hard, so they need the old oil.

This quote from the lube engineer says the exact opposite.

So, the further distinction needed is are we talking about day sail types going out from the slip for a sail where the conditions in your quote are the norm? Or are we talking about people who cruise, live and travel aboard their boats? As the latter, I have frequently (and more often than not) set my Yanmars to 3200 RPM and leave them there for 24 to 48 hours.

That is a normal usage, exactly like highway driving in a road diesel, in my life.
The lube engineer's thoughts about cold, short runs apply more to a vehicle than any marine engine I have owned since living aboard.

A lot of thid discussion really depends on exactly how the engine is used. According to the lube engineer, all generators certainly would need the acid neutralizing high TBN and so do my marine engines, which typically run 24 or 48 hours straight at 3200. Of course, if you just go out for a day sail as your main engine use poattern, you need the lower TBN.

Both right so far....
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Old 25-03-2014, 19:41   #29
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Aside from the gasoline engine distinction, it looks like we have another distinction that is needed to have this conversation.

A64 pilot's argument as to why we cannot use synthetics like Mobil 1 is that marine engines are worked very hard, so they need the old oil.

This quote from the lube engineer says the exact opposite.

So, the further distinction needed is are we talking about day sail types going out from the slip for a sail where the conditions in your quote are the norm? Or are we talking about people who cruise, live and travel aboard their boats? As the latter, I have frequently (and more often than not) set my Yanmars to 3200 RPM and leave them there for 24 to 48 hours.

That is a normal usage, exactly like highway driving in a road diesel, in my life.
The lube engineer's thoughts about cold, short runs apply more to a vehicle than any marine engine I have owned since living aboard.

A lot of thid discussion really depends on exactly how the engine is used. According to the lube engineer, all generators certainly would need the acid neutralizing high TBN and so do my marine engines, which typically run 24 or 48 hours straight at 3200. Of course, if you just go out for a day sail as your main engine use poattern, you need the lower TBN.

Both right so far....
Well your strange then
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Old 25-03-2014, 19:55   #30
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Re: Yanmar Questions

Quote:
Originally Posted by oceannavigator View Post
Aside from the gasoline engine distinction, it looks like we have another distinction that is needed to have this conversation.

A64 pilot's argument as to why we cannot use synthetics like Mobil 1 is that marine engines are worked very hard, so they need the old oil.

This quote from the lube engineer says the exact opposite.

So, the further distinction needed is are we talking about day sail types going out from the slip for a sail where the conditions in your quote are the norm? Or are we talking about people who cruise, live and travel aboard their boats? As the latter, I have frequently (and more often than not) set my Yanmars to 3200 RPM and leave them there for 24 to 48 hours.

That is a normal usage, exactly like highway driving in a road diesel, in my life.
The lube engineer's thoughts about cold, short runs apply more to a vehicle than any marine engine I have owned since living aboard.

A lot of thid discussion really depends on exactly how the engine is used. According to the lube engineer, all generators certainly would need the acid neutralizing high TBN and so do my marine engines, which typically run 24 or 48 hours straight at 3200. Of course, if you just go out for a day sail as your main engine use poattern, you need the lower TBN.

Both right so far....

I think there is some good sense in all of that, but don't forget oil temperature. Car and truck engines, if they have oil coolers at all, cool the oil with hot coolant, or with air. So oil temps reach high levels in cars, usually much higher than coolant temps.

This is not the case with Yanmar marine engines, where the lube oil is cooled by sea water and might not even get up to what would be considered normal operating temperature by terrestrial standards.

But running marine engines for 24 hours at 3200 RPM is way out of the typical use patterns in sailboats. I don't know what Vyv Cox would say about that. Maybe really that demands different oil. Or maybe not -- the oil temps will still be far below what you would find in a car engine. My main engine might run for hours at 2300, but rarely more than that - for hours on end, anyway.
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