posted 12-18-2008 02:25 PM ET (US)        

In an interview with BoatTest.com published in July of 2007, Mark D. Schwabero, then the president of Mercury outboards, said that the improvements included:

--Precision Machined Oil Dams in the Crankcase. By greatly reducing the clearance between the crankshaft and the “oil scrapers”, the amount of oil mass that the crankshaft had to push through and swirl around was also reduced, thus releasing more usable horsepower.

--Eccentric Grooved Crankshaft Main Bearings. This slight change, too, reduced the amount of oil “sloshing” around in the crankcase--and thus robbing power....

Cf.: http://www.boattest.com/resources/view_news.aspx?NewsID=286

There is also a video in which a similar presentation is made by Steve Miller, Verado Platform Manager of Mercury Marine. Mr. Miller explains that the fundamental basis for the improved performance of the Verado was the simple reduction of friction in the engine itself. The power saved from those losses goes right to the propeller shaft output.

Cf.: http://www.boattest.com/flash_video_player.aspx?vol=50&video=mercury/ verado_walkaround )

Is the increase in engine efficiency by these crankcase modification and oil sump designs related to what I often see mentioned as a "dry-sump" engine? I've seen that term used on more exotic racing engines.

posted 12-18-2008 11:05 PM ET (US)            

This saves the resistance of turing a crankshaft though the oil bath. Sort of like running your outboard higher to reduce resistance.

All of the aircooled 6 cylinder Porsche engines have dry sumps.

posted 12-20-2008 09:00 AM ET (US)            

A sump is the place where used oil collects for reuse in a recirculation loop. 2-strokes do not recirculate lubricating oil use a sump although there is some recirculation of oil that collects through recirculation hoses.

The E-TECs do not use a return oil line. The FICHTS use a return line. The FICHT's lubricating system using a return line is analogous to the fuel return line in a fuel recirculation loop of a modern automobile fuel injection system, not a lubrication oil recirculation loop of a 4-stroke outboard.

In the case of an automobile fuel system, the fuel is flowed in a loop from the fuel tank to the fuel pump and then back to the fuel tank. A varying portion of that fuel is diverted to the fuel injectors based on demand. In the FICHT lubrication system, oil is flowed in a loop from the oil tank, to the oil lift pump, to the oil injector and then back to the oil tank. A varying portion of that oil is diverted to the oil injectors based on demand. The recirculation rate in an automobile fuel system is very high as compared to the oil system in a FICHT outboard.

posted 12-20-2008 11:10 AM ET (US)            

I'm thinking of an aircraft flying in a heavy rainstorm vs flying in dry air. It seems to me that for a given airspeed in rain more power would be required than in dry air. Is that a correct assumption?

posted 12-20-2008 07:58 PM ET (US)            

This is just another way to say they improved the efficiency. Improving the efficiency means that you get more HP for the same fuel consumption rate. So, for example, for a fuel burn of the GEN I 225 you now get 250 HP out of the GEN II, 300 out of a 250 etc. No matter how you look at it, they did "renovate" the performance of the GEN I.

posted 12-21-2008 10:27 AM ET (US)            

>>>Joe--Are you saying that in order to improve the Verado to the Gen II level they emulated the E-TEC (and all other two-cycle engines)?<<<

Uh..hardly.

The E-TEC isn;t like all other 2 stroke technology (as been preached on this forum ad nauseum). Do any other current 2 stoke engines do what the E-TEC does in regards to oil distribution?

Dry sump oil systems have been used on 4 stroke engines to improve performance and serviceability probbaly since about 10 minutes after the four stroke was proven to be a viable engine. Racers, both road course and sraight line, have been using that 'technology' since racing began.

posted 12-21-2008 10:30 AM ET (US)            

>>>The E-TECs do not use a return oil line. The FICHTS use a return line. The FICHT's lubricating system using a return line is analogous to the fuel return line in a fuel recirculation loop of a modern automobile fuel injection system, not a lubrication oil recirculation loop of a 4-stroke outboard. <<<

posted 12-22-2008 09:55 AM ET (US)            

There may still be a scavenging system in the crankcase, I am not sure but thought there was a methodology to use the extra oil the crankcase. It would seem logical to return it to the pump system for oil?

posted 12-22-2008 10:33 AM ET (US)            

I am also very confused by SC Joe's account that the improvement engendered in the Verado by the second generation ("Gen II") refinements is something that has "been used on 4 stroke engines to improve performance and serviceability probbaly since about 10 minutes after the four stroke was proven to be a viable engine."

posted 12-22-2008 01:16 PM ET (US)            

Most factory built high performance automobiles don't use a dry sump oiling system, even though a few horsepower could be gained with it's use. Why not? Some don't even have the simpler to install and use crankshaft windage trays. Why not? They can add several horsepower just by keeping the oil from sloshing on the crankshaft.

posted 12-23-2008 10:16 AM ET (US)            

The term for your loss of efficiency is referred to in the automotive world as PARASITIC LOSS.

http://en.wikipedia.org/wiki/Parasitic_loss

posted 12-26-2008 01:04 AM ET (US)            

"Upon introduction, Verado represented a major sea change in technology and how it was applied to an outboard marine application. Nobody else had ever done anything even close to Verado. Therefore, our first priority at the time was to make sure that all of this technology with the performance and driving experience was achieved with the utmost in reliability and durability. As the product has more than demonstrated this in the marketplace over the past several years, it made sense for us to begin work on taking Verado to the next level, which included plans to improve the fuel efficiency...."

From: http://www.boattest.com/Resources/view_news.aspx?NewsID=287

posted 12-26-2008 03:36 PM ET (US)            

My small engine mechanic Pete (40 years exp) is one of the nicest guys you could want to know. I just needed a diesel fuel filter for a gen set the other day, Pete was in the middle of rebuilding a 2 stroke weed eater and I started poking around...we started talking about 2 and 4 stroke engines, (Im still learning too Jim) he said,

"the nice thing about 2 strokes, they always use FRESH OIL"

With that, the comments on this topic have made a lot more sense to me. Thanks all.

posted 12-27-2008 04:15 PM ET (US)            

Based on what has been presented here by people who accord themselves as being really familiar with the topic, I have learned:

--the dry sump or reduced oil sump design has been known to engine designers since the very earliest stages of the four-cycle internal combustion engine, or for about 100 years;

--the dry sump or reduced oil sump design has been used in four-cycle internal combustion engines for about 100 years. However, in spite of that,

--literally no production automobile high performance engines use the dry sump or reduced oil sump design, and this is believed to be because the added cost and added complexity of the design;

--the initial Verado design did not employ a dry sump or reduced oil sump design because (according to the Mercury people involved) their priority was on "the utmost in reliability and durability."

From these assertions (of which none are mine) I make the inference that using a dry sump or a reduced oil sump is perhaps moving away from the utmost in reliability and durability, that is, a lubrication system which bathed the crankcase in oil might lead to greater reliability and durability, but at the cost of some performance. This notion is similar to the one I have heard put forth about the inherent advantage of a four-cycle motor having a pumped oil system in which moving components were generously lubricated with oil.

In opposition to this is the notion that in a two-cycle motor there is a minimum of oil, just a thin film of oil, covering the components, and that lubrication is not excessive. There is just enough lubrication to do the job, and no excess of oil. This seems to be to be the goal of the dry sump designs.

I used to think of a four-cycle crankcase as being full of oil, oil everywhere, oil dripping and sloshing around--all those beautiful parts just drenched in lubricating oil, endlessly being pumped, filtered, cooled, and recirculated.

After learning about this dry sump oil crankcase system, my image of a four-cycle motor has changed. I see it now just like a two-cycle direct injection engine, where in whose dry sump a small amount of oil is carefully distributed and pump to precise points that need lubrication. The crankshaft is not turning in a cloud of oil. I think we describe this:

posted 12-27-2008 11:17 PM ET (US)            

quote:

---

--the initial Verado design did not employ a dry sump or reduced oil sump design because (according to the Mercury people involved) their priority was on "the utmost in reliability and durability."

---

From the Mercury website:

quote:

---

This summer, Mercury Marine proves you can have both increased power and better fuel efficiency as the company unveils enhancements to its Verado® outboard engine line.

In the most significant enhancements since its ground-breaking 2004 launch, engineers at Mercury developed an enhanced power train for the Verado line that gives consumers increased fuel efficiency and power without sacrificing reliability.

Improvements to the power train give the Verado line world-class fuel efficiency. In comparison to the competition, the new 150 hp Verado consumes up to 20 percent less fuel through the power band than the 150 hp Yamaha1, up to 23 percent less than the 150 hp Suzuki2 and up to 40 percent less than the 150 hp Evinrude E-TEC3.

The enhanced power train features forged pistons, precision machined oil dams, eccentric grooved crankshaft main bearings, an all-new intake cam profile, and a new PCM (power control module) calibration. Compared to a cast piston, the new forged pistons provide increased strength and resistance to temperature and wear, added durability and are lighter in weight. The precision machined oil dams significantly reduce the amount of oil allowed to remain suspended in the crankcase. This is achieved by reducing the tolerance between the oil dam and crankshaft lobe and connecting rod.

The eccentric grooved crankshaft main bearings deliver improved oil retention surrounding the crankshaft main bearings and reduce the amount of flow-through to the crankcase.

The new intake cam provides better optimization of top-end power. It significantly improves air flow and allows the engine to produce more power while working less.

The enhanced PCM calibration helps optimize fuel economy at full throttle and cruising speeds.

To showcase the enhanced power train, all Verados will feature a new chrome-polished graphics package. The new four- and six-cylinder Verados are available from your local Verado Qualified Mercury Outboard dealer.

---

posted 12-28-2008 09:57 AM ET (US)            

Of all that text, the portion that bears most on our discussion is this:

"Mercury developed an enhanced power train for the Verado line that gives consumers increased fuel efficiency and power without sacrificing reliability." (Emphasis added.)

posted 12-28-2008 11:22 AM ET (US)            

You need to do some research before you write!

The Chevrolet Corvette Z06,(which last time I checked was a production vehicle) uses a dry sump oil system.

I know that if mercury added a dry sump system to a Verado it would add a lot of weight and a significant amount of hardware to package under a engine cowl.

posted 12-28-2008 12:15 PM ET (US)            

Jimh intentionally mistated that "literally no production automobile high performance engines use the dry sump or reduced oil sump design, and this is believed to be because the added cost and added complexity of the design", in response to something I typed above.

I say he intentionally mistated what I said because he did...I stated: "Most factory built high performance automobiles don't use a dry sump oiling system, even though a few horsepower could be gained with it's use."

The keyword I used there That JimH purposely ignored was 'most'. I think it had previously been mentioned that Porsche uses a dry sump system in some of their engoe designs. I would imagine other exotics like the Ferrari Enzo and probably a handful of other purpose built production performance cars do as well, but I can not confirm this. I do know that most production autombiles that are marketed to be performance oriented do not.

posted 12-28-2008 09:41 PM ET (US)            

So far about all I have done that might have possibly caused SC JOE to become so upset is that I changed his observation that "most" cars don't use a dry-sump design. Now "most" can mean anything from 51-percent to 99-percent, and I don't think that "most" is really a good characterization of the ratio of wet sump to dry sump designs in production automobiles. It certainly is not 51:49. Out of maybe 500 models of cars, so far two have been proposed, and the production volume of those cars is so small it hardly would show up in terms of an overall percentage of production cars with dry-sump four-cycle engines.

Thanks for the data point that a high-performance street race version of the Corvette uses a dry-sump engine. I don't think that really changes the mix of automobiles between dry-sump and conventional-sump by any large percentage. As I understand it, it can now be said that at least one production automobile uses a dry-sump design somewhat similar to the Mercury Verado, albeit a very expensive high-performance version of a production car that is sold in limited quantities.

I have to disagree with the interpretation that the changes to the crankcase design (and here I am lumping this in with the "oil sump") were not intended to improve efficiency. Mercury spokesmen have said that these oiling changes improved efficiency. Perhaps the oil sump itself was not changed. That is not really of concern to me. Perhaps my initial topic should have included the word "crankcase," too.

From my perspective, I see a lot of hair splitting here. I am just speaking in general terms. Mercury is using a oil sump or crankcase design that is not in wide spread use in automobiles, and so far the only examples cited have been in what I would characterize as exotic cars--Corvette and Porsche special edition cars are not exactly in high production.

The dry-sump approach was not undertaken in the original design, which Mercury has said was focused on "reliability and durability." I think it is reasonable to make an inference that if a dry-sump was not used in the original design, and the goal of the original design to was maximize "reliability and durability," then it is hard to make a case that changing to a dry-sump design was done to improved "reliability and durability." Mercury does state that the new design did not reduce "reliability and durability," but that is hardly a surprise. Any spokesman for a company that made a public statement that their new product had reduced "reliability and durability" would be fired on the spot.

However, my logic may be flawed, so I will leave it to the experts to pronounce that the move to a dry-sump design was done to improve reliability and durability. Please explain the mechanisms involved.

The primary conclusion I have drawn from this discussion has been to discover that the evolution of the Verado to its second generation model seems to have followed an approach to the crankcase oiling that has been used in two-cycle motors, that is, a reduction in the amount of oil to the minimum necessary.

The secondary conclusion that I have drawn from this discussion is that apparently there is some reticence to discuss it, or the discussion of it seems to upset some people. I note that almost immediately Glen asked, "Are we having fun yet?" As if somehow the notion that this would be discussed is already frivolous. Perhaps it is of no concern to Glen, but it is interesting to me. And that's why I initiated the discussion.

posted 12-28-2008 11:05 PM ET (US)            

I'm not upset...and never have been. I find that description of anything I have typed or even my mood as odd, at best.

And I'm not changing any observations on how many cars use/don't use dry oil sump designs. How could I? I copied and pasted my own comments as evidence that showed that! Again..not sure how you came to that specious conclusion.

Regardless..I stand by "most cars" do not use a dry oil sump design. Simply, most cars don't. I do not have an exact count on how many that do, versus how many that don't, do you? Since I don't, and I think since it might be difficult (and really pointless in this example) to obtain that number, I think "most" summarizes that description pretty well. You seem to look to find an issue where there is none, and disagree..as typical.

I often find your "relentless pursuit" of "collecting good information" seems to be the correction of trivial descriptions--your own "trivial pursuit", so to speak. In the past, you've needlessly corrected me on the syntax of "E-TEC", the correct use of the "HO" in the E-TEC "HO", and on Mercury engine model year designatons (regardless and in opposition of what my state gov't mandates). While these topics might be important (to someone, somehow..I suppose), they certainly can't be considered material or even important by almost anyone.

In contrast, I've never seen you edit anyone on the correct use or elimination of "F" used in the description of the four stroke Yamaha "F150", or the "C" in a premix Yamaha "C115", or even the "DF" when used to describe a Suzuki four stroke engine.

Is there a semantic difference that's not obvious to me? One person might say the problem is an Evinrude/Mercury bias, while someone else might say it's simply a personality clash that you seem to have. Were the latter the case, I'm certain it would be simple enough to ban me from posting.

posted 12-29-2008 09:40 AM ET (US)            

Regarding my use of the term "sump" to refer to the general arrangement of lubrication and crankcase design, in this regard I follow the practice of Mercury. They use the term "integrated dry sump" to describe these engines. I don't think my use is significantly different or misleading. In the initial sentence of the article that begins this discussion I included the word crankcase:

"... in four-cycle engines there might be some influence on the overall engine efficiency from the design of the engine oil sump and crankcase."

While the precise nature of the oil sump itself may not have changed or may not have influenced the efficiency of the engine, the changes in the crankcase design and its lubrication have influenced the efficiency. Indeed, that is the whole focus of the discussion.

posted 12-30-2008 01:32 PM ET (US)            

The old air-cooled Porsche 6 cylinder engines used dry sump lubrication, but required 12 quarts of oil. The newer, water-cooled Porsche boxer 6 cylinder engines might have a different system & require fewer quarts of oil. But they are still designed to keep oil flowing during hard cornering.

posted 12-30-2008 10:32 PM ET (US)            

Easy with "most". It's apparently not a good descriptor.
And "most" cars don't even use a baffle.."most" just let the oil slosh around the crankshaft.

What is probably the highest quantity produced transportation that uses a dry sump oil system?

posted 01-05-2009 07:22 AM ET (US)            

I think this is the main reason why dry sump is used.

"The old air-cooled Porsche 6 cylinder engines used dry sump lubrication, but required 12 quarts of oil. The newer, water-cooled Porsche boxer 6 cylinder engines might have a different system & require fewer quarts of oil. But they are still designed to keep oil flowing during hard cornering."