Engine choice in 300-400hp range

[Baker]

I think I have an idea of what most people prefer in the low load range(Lehman 120/135, Perkins, Deere, etc.).

I am wondering what your preferred engine would be in the 300-400hp range to push a 40ish sized motoryacht to planing speeds.* Feel free to add your comments as well.

We are not directly in the market but will most likely be in the coupla years.* My choices(mostly ignorant) would be the Cat 3208TA followed by the Cummins then Yanmar then Lehman then Detroit.

The Cat and the Cummins simply because there are so many out there and they have great reputations and parts are easy to come by.* Yanmar is kinda new on the scene but certainly would not see anything wrong with them.* My only concern is that they have a tendancy to have the Yanmars pretty tuned up and maxxed out which could be argued would lead to a shorter life span(I have a 4LHA-STP at 240hp in my boat.....240hp out of 211 cubic inches....that is more power per CID than most gasoline engined cars).* I put Detroit at the bottom because they always seem to be loud and smokey and thirsty.* The Lehman down there simply because it is a little low on power(275hp) for what I was thinking.

-- Edited by Baker at 21:41, 2007-10-15

 

[Brent Hodges]

Hi John.
As much as I like my 135 Lehmans, I sure wouldn't want the higher hp versions. They (the 165hp & up) are sleeved engines and prone to problems that the 120's and 135's aren't. Bob Smith talked about some of these problems when I took his diesel course, but I don't remember much about them, since I had the "good" ones. Some of the parts are harder to get on the higher hp models also, since a lot of the "outer" parts on his current model 140 also will fit the 135's.

Another thing I like about all the bigger in-line 6's over the 3208's and such is how much room they leave in a twin engine room.

 

[Carey]

John
**** I put in a new 3126 (420hp) several years ago. It has been very good to me, with no problems whatsoever. With a single, it gives my 36' boat a fifteen knot cruise. It's comparatively quiet, light and low maintenance. Fuel economy is as good as any, and parts are and will be redily available wherever you go. It's a sweet sounding thing as well. I've only got 1,100 hrs. on it, so who knows what the future will bring.
**** If you are happy with 300hp, then the 3116 is an option, and I would definitely take a look at the 300horse John Deere. I know of a lot of folks around here who have used the Deeres in the last five or more years. They are very happy.

 

[Codger2]

I've had Perkins, Detroits, cat 3208's, Cummins 5.9 210hp's and a cummins 5.9 330B. I must say that from a maintenance point of view, the Cummins win hands down. Easier oil fill, (you can change the location of the filler) and the 6 cylinders run like a sewing machine.

 

[FF]

Assuming the boat will actually use 300hp , rather doubtfull as thats about 15gph there would be only one choice for me.

A DD Series 60 , cheap to keep , over 1,000,000 miles in trucks with ONLT minor (oil & filters) .

As I prefer a keel cooled and dry stack for any cruiser a simple truck takeout* would save 90% of the co$t of a marine unit.

Down in the 100 -150hp RANGE* THE iNTERNATIONAL DT 466 is a lighter and even cheaper unit.

Unfortunatly both these selections use electronic fuel controll so with all the "modern" marine engines the oars will be required in a thunderstorm , if not in a metal boat.

At least these engines are not car (yanmar) based so can expect to live with heavy loading and get thousands of operating hours* working hard.

FF

 

[Trawler Gil]

I've had boats with tyhe following, Yanmar 6LY, Cummins 5.9, and JD 6068.* I'm also looking at choices right now in hopes on getting a different boat with engines in this very range.* Here's my opinion of my past engines:

Cummins, 5.9:* Great engine, manufacturer performed service (BIG Plus), built for easy service (how many modern engines can you change the impeller out without removing the pump?).
Yanmar 6-LY:* Not real thrilled with higher RPM diesels.* Dependent of non factory service.* Poor air filter location design.* No maintenance problems, self priming fuel system.
John Deere 6068 (Electronic engine): Dependent of non factory service.* Relative new comer to the marine market.* No smoke at start, no smell.* No maintenance problems, self priming fuel system.* Wealth of user accessible data through the elctronic controls.

This is what I found looking at new engines:* I looked at Cummins, Yanmar, and Volvo.* I didn't look at John Deere solely because it wasn't an optional engine on the boats I'm looking at.* Although not on my radar before, I'm inclined to go with the Volvo D6.* It's specs indicate it has a slight advantage in fuel economy and noise.* It also appears to have a better power curve.* They claim to have some real service benefits as well.* My next choice would be the Cummins, but it's also the most expensive by quite a bit.* I also discovered that Yanmar has 2 six cylinder offerings with the lower HP unit still using a mechanical fuel delivery system.* I believe this is the only Tier II non electronically controlled fuel delivery supply engine.

BTW, I didn't consider CAT or MAN as I don't believe their the engine of choice below 400HP.

Gil

 

[Baker]

Great replies!!! My only hesitancy about the Cummins 6BT is that as I shop for boats(which is continuously), I seem to always notice a large number of Cummins powered boats where one engine is "freshly rebuilt"while the other one has relatively low time on it(1500ish). I have rarely seen a Cummins with 3000 hours or more on it where that is fairly common on Lehmans and even Perkins(is that a fair comparison). And since these engines in question are turbocharged and heavily loaded, is it fair to expect thousands of hours of engine life out of them or is 2000-3000 hours considered "high time"?

 

[FF]

If saving money matters, remember fine engines like Deere have been created for the construction and farm industry.

A factory rebuilt is loads cheaper than factory new , yet carries a factory warentee.

WET Exhaust manifolds are available fro aftermarket sources , should they be needed .

Best of all the factory WAIVES the requirement for a rebuildable core once or twice every year,

The 4 and 6 cyl Deere are probably one of the best choices for modest power.

The Detroit Series 50 , would be a good 250 hp choice.
Cheap! from Transit Busses (which are thrown away ) at the 10-14 year point regardless of condition.

And you wondered where all those highway gas taxes were thrown away?

FF

 

[North Pacific Guy]

Never owned any to these expecpt the Cummins QSB 380.* Tony, the engine guru on boatdiesel.com really likes the Cummins.

 

[FF]

"I seem to always notice a large number of Cummins powered boats where one engine is "freshly rebuilt"while the other one has relatively low time on it(1500ish). I have rarely seen a Cummins with 3000 hours or more on it where that is fairly common on Lehmans and even Perkins(is that a fair comparison)."

Some engines take better to poor storage , some worse.

Perhaps you check with the lobster folks , who run 5 -7 days a week.

If they get good hours , and the yachts do not , its probably improper storage.

Most engine Mfg have strict requirements for "out of service for over 30 days" , most yacht folks seldom bother.

FF

 

[Trawler Gil]

FF, it's not fair to compare apples and oranges, even when thy come from the same basket.* I believe you will find that the lower HP rated engines will always last longer than the higher HP units based on the same engine.* I know that Cummins 180 or 220HP 5.9 were far less problematic than the 370HP version of the same.

I suspect we'll see somewhat of a leveling of engine life between electronically controlled engines of varying HP, although I have no basis for that assumption.

Gil

 

[FF]

" I believe you will find that the lower HP rated engines will always last longer than the higher HP units based on the same engine."

If you check on any good engine site you will find a bunch of ratings. M1 thru M5 all for the same basic block.

The difference is how long the engine can be expected to live with the given loadings.

The M1 is 24/7/365 a REAL cruising boat engine , that can perform at that level till worn out.

Lightweight auto and other takeouts , or built for outdrives , Yanmar Volvo , and some others are great engines IF and only IF the mfg recomendations are followed.

Many ONLY have a M5 rating , pleasure boat 300 hours a year with a VERY small amount of full throttle (gets the skiers up) allowed.

My ancient 6-71N at moderate power settings will give 5000 to 10,000 hours IF MAINTAINED.

The exact same engine with turbos and aftercoolers will run 1000 hours in a Sports Fish , and the captain will kiss the mechanic! 450 hp takes a toll, 100 hp is far easier to live with.

Interestingly both engines will have consumed about the same amount of fuel to get worn out.

Just one gets worn out 5 or 10 times faster , speed co$ts!

FF