Thoughts on Engine Preference

[rtpelagic]

OK folks, here's one for you.

Which engine would you prefer, and why, to push a 34,000lb full displacement 39' trawler? Assume primarily coastal crusing with future plans for extended cruising away from the US. Assume engine is powering nothing but a prop and an alternator (no water maker pump, etc.)

American Diesel 6N140 (naturally aspirated, in-line 6, 140hp)

or

John Deere 4045 TFM (turbo, 4 cyl, 115hp)

Cheers!

 

[DavidM]

How about a factory remanned (virtually new), Cummins 6BT 210 hp.

But given the two choices, I would go with the JD. It has a balance shaft so will be smooth for a 4 cyl. Low boost turbo, modern design, heavy block. Also I was under the impression that new Ford Lehman equivalents from American Diesel were no longer available.

David

 

[Nomad Willy]

The JD for sure but you probably don't even need that much power.

 

[Darylat8750]

I'd go for the John Deere and prop it for the M1 rating. It's a tough engine and they are used on pumps,generators and other equipment all over the world. Like Eric said I would consider something smaller.

 

[rtpelagic]

Thanks folks. Actually these are two engine choices already installed in different hulls of the same make of boat we are shopping for. The boats are essentially equivalent in layout, systems, age, hours, etc, with the engine type being the only real major difference. Was just seeing if there would be a general preference of one over the other. Seems like the JD is going to win based on early results.

 

[markpierce]

The JD for sure but you probably don't even need that much power.

Then get the normally aspirated 80 h.p. version of the JD4045.

 

[sunchaser]

Not so fast now! There are a few other things to consider yet.

The JD induction system is more complicated with a (after cooler too??) turbo. I'd guess the JD is electronic as well vs mechanical for the American Diesel 6 cylinder. The JD is pulling about 20% more HP per cylinder and possibly 30% more based on CID. The 4 will be rougher than a 6, balance shafts can only do so much.

PO care and attention plays a role too, not only in all things mechanical and electrical but cosmetic also.

If all is equal except engines, what is the price differential?

 

[Nomad Willy]

Yes I agree w Mark.

I think the original poster is looking at 40'Willards. Takes 23hp to go 7 knots w the Willard 40. A 55hp Yanmar would (I believe) power the W40 adequately. Our automotive culture has taught us we need lots of extra power and we're constantly in denial about what we actually need in cars or/and boats. Better to have too much than too little and I fully agree. But w my 30' Willard I've not used more than 20hp in the 8 years I've owned her ... Other than increasing 200rpm just because I felt like it or to put a bit of higher load time on the engine. And of course checking that all is well mechanically and that I can still achieve my rated rpm of 3000.

 

[rtpelagic]

Actually, we looking at the Krogen 39. The JD is pretty much standard in that boat. There is a one and only with the AD 6N140. There is about a $10K difference in asking price, the AD being higher. Who knows where you will end up after negotiations as the asking prices are all in the same ball park.