Need to repower.

[Conrad]

Due to a nasty overheating incident it looks like we will have to repower. The old engine, a Volvo TAMD 40A, is not worth rebuilding according to every diesel shop I've queried.*

So, we are looking to repower with new, and are looking at a John Deere 4045 turbo (don't know the exact model #) at 150 HP or an Isuzu 6BG1 at 135/140 HP.

Dollarwise they are similar, with the Deere having a slight edge, but the Isuzu is a 6 cylinder naturally aspirated while the Deere is a 4 cylinder turbo. Our preference would be to go naturally aspirated with more cylinders.

Th engine will be going in to a 32' semidisplacement boat that we cruise at 7.5 knots but would like to have the option of 10 (or so) knots when required for passes etc.

*

Anyone have any thoughts or experiences re these two engines?

 

[Tidahapah]

I think first look at the weights of the engines, HP at what RPM are you going to use the same gearbox or change gear box and prop.
What is the weight diff. Length and width diff re mounts.
If all was equal the Isuzu would be good being NA but the less HP and what is the RPM diff.
Is the JD an electronic engine, if so for me that would rule it out. If not then smaller engine more HP most likely less weight but probably higher RPM probably a serious contender.
Too many variables to say much with out all the data.

 

[Jay N]

Don't rule out a Cummins rebuilt 210hp*for economical/reliable service, probably about the right sized engine for your needs if you have sufficient room.* These engines can operate lightly loaded without much concern.

If the dollars are similar,*I would look to the Cummins in lieu of a new Isuzu, which I installed in a previous boat in 1980 with their D500 model.* But maybe their marinizations have improved since then.

The John Deere/Lugger's are great engines.

 

[Delfin]

I had a 75 hp Isuzu in my prior sailboat and loved it. *Based on the specs I can find, the Isuzu looks like the more robust engine. *From a longevity perspective, the more weight in a diesel, the better, and the Isuzu has more metal. *The Isuzu also wins on displacement, which means it will develop more hp at a lower rpm than the Deere, which translates to longevity. *I'd like to see the power curve on each engine, but a fast response is that the Isuzu is the more robust. *However, the marinization of the Deere may be superior, so that is an issue to explore before deciding.*

I also don't see the Deere going up to 150 hp in that model, just 140 hp.

 

[Nomad Willy]

I'd go w the Isuzu. Klassen has been marinizing Isuzu's at least back to the early 70s and lots of old fish boats have umpteen hours and years on them. Klassen is a Canadian company and one of the special things I like on their engines is the steel exhaust manifold. Better than anything else** ...I think. Their BC operations are down in the Delta area. PM me for a phone # if you like. I wanted the Isuzu for Willy but they did'nt have the correct size.

 

[FF]

Can you do a marinization?

The Iveco (fiat) would also be a choice.

Volvo may offer factory rebuilts , might be worth a call.

I would opt for the simplest newer engine that would meet any local air police rules.

Electronic engines are great about 15% lower fuel burn, BUT a nearby lightning strike may cost a $6,000 black box or (6) $1000 each injectors.

Same with a turbo , great IF the engine is small enough to actually load the turbo at your LRC cruise speed , otherwise just another expensive maint. item.

I would use your existing knowledge of your boats fuel burn at various speeds to determine what you actually can use to cruise.

Find the MFG 24/7 hp chart and see if you can match it to your old fuel burn , use 15hp from a gal an hour in estimating the hp produced by your old engine.

 

[Conrad]

Thanks everyone for the thoughtful responses. This morning we determined that in fact our engine did survive the overheating incident so we will not be repowering for the moment. However, given the age & condition of the Volvo we may be facing this question again in the future.

Things may change in the interim, but we currently would be leaning toward the Isuzu I think.

In response to your comments:

Both engines, the John Deere 4045TFM and the Isuzu 6BG1 are non-electronic models with very similar dry weights: 1060 lbs (Isuzu) vs 1019 lbs (JD) without trannies. This is very similar to the existing Volvo.*

The displacements are quite different though, with the JD coming in at 275 c.i.d. vs the Isuzu's 396 c.i.d.*

I believe this JD model is only available now in Canada (not the U.S.) as a non-certified engine but it is definitely 150 HP. It may be the certified model that comes in at 140 HP, I don't have that data in front of me.

RPM ranges are similar to each other and are in fact at least 500 RPM lower than the Volvo.

Good question on the marinization of the Isuzus. As Eric mentioned, I assume that it is done by Klassen, as they are the distributors.

Apparently the Lugger does not come in the size range that we are looking for, and the Cummins would not fit.

Transmission options for both would fit our needs as there are a relatively wide range of reduction ratios available and all will rotate either way.

The JD is considered to be a shaker by some, but that is only at idle; up a hundred RPM and everything smoothes out.

Some other options we looked at were a rebuilt Volvo 41 (it has a number of letters in front of the "41" but I don't recall them exactly) which would bolt right in, but the price was in the range of the new JD and Isuzu; and a Yanmar type 4BY2-150. The Yanmar was slightly more expensive and was all electronic including the controls. The big knock against the Yanmar in our view is that it is a light (569 lbs), high revving engine - approximately 1000 RPM above the others at normal cruising speed.*

The Isuzu dealer is also high on the Iveco, although not quite as high as on the Isuzu (he sells both). Having owned a Fiat 124 Spyder in the distant past I would NEVER own another Fiat. Yeah, I know, probably apples and oranges, but nevertheless.

The Isuzu is a big hit with the commercial guys around here which is a significant endorsement I'd say.

And it turns out that the Isuzu would fit via modifying the pan while there is no chance with the JD as it is too tall.

Thanks again for your thoughts.

*

 

[FF]

IF you will do the marinization the International DT 360 or DT 466 would be my first choice.

A marine injected ( not pick up truck) Cummins 5,9 would also be fine , and really inexpensive , compared to "marine".