which engine for 280 sundancer

Presentation said:
In my opinion, the 280 Sundancer with a single 6.2 small block is underpowered.

That is why Sea Ray discontinued offering this combination.
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That and they had a 7.4 big block replacement in the 496
 
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2000SEARAY280SS said:
you gotta love the twin vs single debates

i have twins and its twice as much everything
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Just in case others read this then think I am saying all single engines do not have enough power for the 280 Sundancer, that is not what I am saying.

Here is my opinion as it relates to the Sea Ray 280 Sundancer:

The GM 8.1L = 496ci = “big block V8” products a lot of tork (lower RPM power) and can get this boat to gitty up quite well.

The GM 7.4L = 454ci = “old big block V8” in my opinion did OK and so long as you are at the lighter end of the passenger and gear onboard and lower end of the performance expectations. This engine is acceptable.

The Mercury 6.2L =377ci = “small block V8” an engine that begins life as a GM 5.7L that mercury tweaks. Mercury actually did a pretty good job; actually mercury did an excellent job at tweaking this engine. They got it to pump out 320 horse power, more horse power then the 7.4L big block V8 and 20 more horsepower then the GM 5.7L small block V8 but the engine has a Achilles' heel.

To understand the Achilles heel you need to understand horse power. Horse power is tork times RPM. The 6.2L is a ‘relatively’ high revving engine at 5200 RPM vs 5000 for the 5.7L small block V8.

Mercury will never publish a tork curve like GM does on its engines. But I (and many others) know where Mercury found those extra 20 ponies. They are at the very top of the chart, right at the RPM limit. At lower RPM’s the tork is about the same at the 5.7L small block V8.

So if you put this engine in a heavier boat and you are trying to get on plane, it’s not horse power at wide open throttle that is going to get you on plane because the engine is not at maximum RPM at those speeds, it’s the tork.

So the top speed on a 280 Sundancer with the 6.2L small block V8 will be pretty good compared to the 7.4L big bock V8 but you will always need a light load to get on plane.

This engine is good for dock queens, and there is nothing wrong with that. I know a family with a big boat that has not had a working engine for the last several years. The boat is there vacation home.

If you plan on going boating with other people, the 6.2L small block in this heavy of a boat is under powered in my opinion.
 
Presentation said:
Just in case others read this then think I am saying all single engines do not have enough power for the 280 Sundancer, that is not what I am saying.

Here is my opinion as it relates to the Sea Ray 280 Sundancer:

The GM 8.1L = 496ci = “big block V8” products a lot of tork (lower RPM power) and can get this boat to gitty up quite well.

The GM 7.4L = 454ci = “old big block V8” in my opinion did OK and so long as you are at the lighter end of the passenger and gear onboard and lower end of the performance expectations. This engine is acceptable.

The Mercury 6.2L =377ci = “small block V8” an engine that begins life as a GM 5.7L that mercury tweaks. Mercury actually did a pretty good job; actually mercury did an excellent job at tweaking this engine. They got it to pump out 320 horse power, more horse power then the 7.4L big block V8 and 20 more horsepower then the GM 5.7L small block V8 but the engine has a Achilles' heel.

To understand the Achilles heel you need to understand horse power. Horse power is tork times RPM. The 6.2L is a ‘relatively’ high revving engine at 5200 RPM vs 5000 for the 5.7L small block V8.

Mercury will never publish a tork curve like GM does on its engines. But I (and many others) know where Mercury found those extra 20 ponies. They are at the very top of the chart, right at the RPM limit. At lower RPM’s the tork is about the same at the 5.7L small block V8.

So if you put this engine in a heavier boat and you are trying to get on plane, it’s not horse power at wide open throttle that is going to get you on plane because the engine is not at maximum RPM at those speeds, it’s the tork.

So the top speed on a 280 Sundancer with the 6.2L small block V8 will be pretty good compared to the 7.4L big bock V8 but you will always need a light load to get on plane.

This engine is good for dock queens, and there is nothing wrong with that. I know a family with a big boat that has not had a working engine for the last several years. The boat is there vacation home.

If you plan on going boating with other people, the 6.2L small block in this heavy of a boat is under powered in my opinion.
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Just sayin'... HP=torque x rpm/5,252
 
Again - my contention is that twins are more exposed to damage and I have observed such damage. This contention is supported in TWO PUBLISHED ARTICLES (supra) in this thread. The first article is here for reference:

http://www.passagemaker.com/Magazine...8/Default.aspx

The second article is as follows:
http://www.oceannavigator.com/ME2/dirmod.asp?sid=&nm=&type=Publishing&mod=Publications%3A%3AArticle&mid=8F3A7027421841978F18BE895F87F791&tier=4&id=CADEB890F8D040F2AC33CDC44A8A72CA

“Twin engines
The advantages of twin engines are well known — safety, maneuverability, and shallow water access. Twin engines give you the safety of a backup propulsion plant — a get-home engine. In addition, you have the ability to cannibalize parts from the comatose engine to keep the surviving engine running, should you need to. There’s also the added benefit of greater maneuverability in close quarters, often the primary reason for twin engine installations. And finally, there’s the ability to bring the boat into more shallow, more interesting coves and inlets.

However, these advantages come at some additional cost: two engines, shafts, props, rudders, cooling and exhaust systems, etc., plus increased fuel consumption, and, since the shafts and rudders are off the centerline, they are more exposed to damage from floating and submerged debris and groundings, unless they are to be protected by skegs or bilge keels, and thus more cost.

Single engines
Single engine installations also have their advantages, lower cost, less noise and vibration, greater cruising range and superior prop, shaft, and rudder protection.”I quoted the “Twin Engine” section above for fair presentation even though the author – later in the article – goes on to dispel many of the twin safety myths.

Since other folks said they knew NASA scientist, I decided to include an article from NASA regarding GSE (Ground Support Equipment) regarding "Redundancy in Critical Mechanical Systems." It's the best article I could find regarding defining situations similar to the conditions imagined for the need of a twin on a boat. As far as a twin power plant on a cruiser, it doesn’t pass any of the definitions.

http://engineer.jpl.nasa.gov/practices/3003ksc.pdf

If responders can find published articles rather than their opinion to support their contentions, the reader should consider those references.

A scenario is offered to the reader - When one experiences damage on one of their twin outdrives, they are so glad they have a spare and thus congratulate themselves on their forethought in determining the need the twin for safety as they limp back home – that is, if they can make it back home due to the drag and dramatically reduced fuel economy. In the alternative, It may very well be that the single, because of better protection as confirmed in these two articles, would have avoided the damage altogether and would be happily and safely boating or at home .

Finally, this whole thread has piqued my interest in this issue. For instance, I strongly disagree with other statements in this thread regarding the hydraulic dynamics of a planning hull vs. a displacement hull. It points out that this entire debate needs to be resolved. It’s interesting because there are more than mechanical issues. I believe it has some stochastic elements as well, so probability is an issue. So I propose writing a peer reviewed paper as time allows. If anyone wants to co-author, send me a PM.

Thanks – and safe boating to all
 
Go with the 5.0's if you can. Have driven both 4.3's and 5.0's on a 280 and it's nice.
 
My vote is single big block.. In my older 290 the twin 4.3's are just too crowded . Plenty of power out of the hole with the B3, backs down easier than the old 20 footer
and its nice to not buy two of everything at maintenance time.
 
Moose said:
Go with the 5.0's if you can. Have driven both 4.3's and 5.0's on a 280 and it's nice.
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If I go with twin engine boat it wont be a 28'er I would start at 30'-31' minimum.
 
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The one vs. two engine discussion is a good one. I still have no idea whether one engine is better than two or the other way around, even after reading the attachments.

I will say, however, that we were on the Chesapeake last summer in some tough weather. We slowed the 280 down considerably owing to three or four foot swells/waves and a heavier than normal northerly wind.

A charted one hour trip at twenty-two knots became a three hour trip at seven or eight knots. I believe that we could have continued on to safety on one engine if the other went down.
 
The one vs, two is definitely an interesting one. There are plenty of pros and cons for both configuration. For me after tons of reading, I determined either configuration would work for me. I ended up with the T5.0 mainly because it was the right boat at the right price at the right time that came along. Fuel was one of my biggest concerns and I found that based on fuel numbers others were reporting, there was not a very big difference between the single 496 and both twin configurations as far as that goes. I have never been on a 496 but everyone that has one seems to be pleased with power. I have been told some go with the T4.3 for the engine room space. It appears to me that with the T4.3 you get more room in the front but the engine risers seem to be alot closer together than mine.

Echoing what many others have said here,
I think the 3 main advantages to the twins are-
Better handling around the dock.
Higher resale (due to larger market)
Engine Redundancy for Ocean boating

Three main dis-advantages are-
Higher Initial Cost
Increased Engine/Outdrive Maintenance
Less Engine Room Space

Since I am close to the ocean, I like the idea of being able to trailer my boat to the ocean to take it on the intercoastal and would feel better having twins out there.

I would like to take out a 496 sometime to try it out and see the difference.

Jason
 
It doesn't matter how cut this versus that. What really matters... when your 3 miles out and your one engine doesn't feel like working anymore. If you can afford it, get twins.
 
I had twin 3.8s stern drives in a 28 footer by 10.5 beam, Weight wet was 9,000#. Not a SR. There was little room to work on the engines. If I was to purchase a 28 footer I would go with a single as you get to pay twice for maitenance on the drives and a single you can work around.
 
The twin 4.3's gives you a lot of room to get into the ER and move around, unless you're fat.
 
I crawled around in a 280 with a single and it's a dream to work on, but didn't fit my style of cruising. The 5.0's have a little more umph, but boy is it tight down there. I opted for the 4.3's which have plenty of power, with the middle of the road room between the 3 power packages. That's what's great about the 3 packages on this boat. you can pick the one that fits your needs.
 
TurtleTone said:
The twin 4.3's gives you a lot of room to get into the ER and move around, unless you're fat.
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Yep hate to admit it but I fall into this category. :smt001

Thats when I call my wife. Still love the twin 5.7's though. I know mine is not a dancer and it may be even a little smaller.
 
twin 4.3 for 280

I've read and searched but can't seem to find a really clear answer on this. I'm looking at my first "larger" boat. I've always had 20 foot or less runabouts and have lots of boating experience but never with these larger boats. The used boat I'm looking at is the searay sundancer 280 with twin 4.3L MPI. They are not the bravo 3 they just have a regular prop on each outdrive.

My question is are these the best option? What would be the ideal engine if this is not the best. And maybe some info on what I could expect from a fuel usage?

Thanks
 
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