KAD 44,300 vs D6 310,350

[Oculoplastics]

Dear all

I am thinking of buying either a Princess V42 or a Fairline Targa 40 between 2003 and 2006. Depending on the year, they are fitted with either the KAD series or the D series.
I would be extremely grateful if people who know those engines can comment on which engine is safer to go with.

I know the following:
KAD
Older engines, out of production, with more smoke than the D series, easiear/cheaper to overhaul, no electronics, higher consumption.
D
Newer engines, still in production, less smoke, extremely expensive to overhaul, a lot of electronics, fuel economy.

All authorized VP dealers I have had a chat with are pro the D series for some reason.

Thanking you all in advance.

 

[Momac]

You have summed it up nicely .

 

[oldgit]

Usually amounts to a small amount on start up and should vanish on warm up or few moments after moving off.
Have had the earlier versions of these engines both the 40A and the 41B, shaft and outdrive ,both were fairly high hours and well maintained, neither were prolific smokers even from cold.
As for the alleged fuel saving, would very interesting to compare fuel burn figures bearing in mind nobody spends their boating are WOT and much boating spent at slower speeds during most day trips out.
When underway on the plane doubt anybody able to detect which engine version is moving the boat ?

 

[petem]

You have summed it up nicely .

No he hasn't!

KAD44 and 300 both have electronic governers, metering, throttles and diagnostics. And they're not smoky. apart from that he was spot on !

 

[simonfraser]

Brand new, far less hassle than a 20 yr old VP …

mobo

 

[SC35]

Although my D4’s have thrown a couple of big bills at me, I still prefer them over the KAD series engines I had previously.
At some point, parts for older KAD engines will become harder to get.
D series engines use substantially less fuel when planing, although I don’t have the figures to hand.
They are also smoother and smoke free, even in cold weather.

Also KAD44/KAD300 are at the ”tuned up“ end of what’s possible with that 3.6L block and a DP-E or DP-G Drive,
A D6-310 or similar with 5.5L block and DP-H are in a comparatively mild state of tune given that you can get a D6-400 with the same drive.

 

[PowerYachtBlog]

For the V42 I would go with the D6 5.5 litre engine, does not matter the HP, but the bigger is better for the 10t plus of the Princess.
The Princess is heavier then Fairline Targa 40, about a ton to 1.5 (1000 kg) more.
More length a bit more beam (10 cm) and over all a bigger boat.

With the Targa 40 I would go with both Kad44s and 300s. Less problems, easier to do your own general maintenance, and most stuff is cheap much cheaper.
Going with the D6 is a waste of money on the Targa 40.
They top 32 knots max with Kad 44s, and 35/36 with with Kad300.
As for tuning up being on the limits as long as the boat is not over weight to the engines and you are at 80-90% load on her it is not problem.
With Kad300 a Targa 40 will be at 80/85% load at 3100 rpm at about 27 knots cruise speed. Total consumption of about 70/80 litres per hour.

 

[bluetooth]

Here are some links

Kad 300 v D6 in Targa 40:

Kad 300 v D6 in targa 40

Fairline Targa 40? :

Fairline Targa 40?

Technical links (all Targas)

 

[oldgit]

Fuel efficiancy claims .
Lots of stuff regards "D" series and much older engines virtually nothing on KAD. 300.



Even the out of the stone age Yanmar 300 hp is easy to find.
YANMAR.

 

[MapisM]

Fuel .
Lots of stuff regards "D" series nothing on KAD.

It's actually the other way round, in my experience.
In fact, I never came across tech sheets as deailed as the attached one for the D series.
But before anyone ask, sorry, I don't have the same PDF file for the other KADs.
I looked for this of the 43s back in the days when I had a boat powered by them.

 

[oldgit]

Sorry, should have more specific , trying to find out if the increased fuel efficiency claims for 300hp D6 over the KAD 300Hp are marginal
or impressive.
Cannot find any KAD300 graph to directly compare to the D6 of identical horsepower.

 

[MapisM]

Impressive improvements in fuel efficiency is something you can only find in brochures, not in real world.
If you check the only number that really matters for fuel burn, i.e. the BSFC, you will see that marine engines have been in the 220 g/kW-hr ballpark for decades, and still are.
Electronic governors, common rail, HEUI or MEUI injectors, sequential turbos... You name it.
All impressive innovation, in many ways - fuel efficiency improvement just ain't one of them.
For each 100 hp of power output, you had to burn 20 liters of fuel/hour in 1983 and you still have to in 2023, period.
I wouldn't say that the differences between all engine models (even across different manufacturers) are laughable, but almost.

PS: what did change significantly is the engine displacement required to produce any given power.
In turn, this means that the power to weight ratio is now better, and the spaces taken by engines are smaller, freeing internal boat volumes for living spaces.
And theoretically, better power to weight should also mean lower fuel burn in any given boat, AOTBE.
Trouble is, in order to exploit internal volumes as much as possible, hull efficiency became less of a priority for designers, so the weight advantage doesn't materialze in better fuel efficiency overall.

 

[ari]

The D series replacement for the KAD 44/300 is the D4 (similar power, similar capacity). The D6 is a major upgrade.

Also, the KAD 444/300 is an upgrade of an upgrade of an upgrade of an... They started off as TMD 40 at 130hp before becoming TAMD 40 (165hp), TAMD 41 (200hp), KAD 42/43 (230hp), KAD 44 (260hp) and finally KAD 300 (285hp). It dates back about 40 years and have been out of production for almost 20 years.

 

[PowerYachtBlog]

Impressive improvements in fuel efficiency is something you can only find in brochures, not in real world.
If you check the only number that really matters for fuel burn, i.e. the BSFC, you will see that marine engines have been in the 220 g/kW-hr ballpark for decades, and still are.
Electronic governors, common rail, HEUI or MEUI injectors, sequential turbos... You name it.
All impressive innovation, in many ways - fuel efficiency improvement just ain't one of them.
For each 100 hp of power output, you had to burn 20 liters of fuel/hour in 1983 and you still have to in 2023, period.
I wouldn't say that the differences between all engine models (even across different manufacturers) are laughable, but almost.

PS: what did change significantly is the engine displacement required to produce any given power.
In turn, this means that the power to weight ratio is now better, and the spaces taken by engines are smaller, freeing internal boat volumes for living spaces.
And theoretically, better power to weight should also mean lower fuel burn in any given boat, AOTBE.
Trouble is, in order to exploit internal volumes as much as possible, hull efficiency became less of a priority for designers, so the weight advantage doesn't materialze in better fuel efficiency overall.

This is not far away from the truth, It is an average though. That is why in some cases lpm is what matters the most, because only in that you see the real truth.

 

[petem]

For the V42 I would go with the D6 5.5 litre engine, does not matter the HP, but the bigger is better for the 10t plus of the Princess.
The Princess is heavier then Fairline Targa 40, about a ton to 1.5 (1000 kg) more.
More length a bit more beam (10 cm) and over all a bigger boat.

With the Targa 40 I would go with both Kad44s and 300s. Less problems, easier to do your own general maintenance, and most stuff is cheap much cheaper.
Going with the D6 is a waste of money on the Targa 40.
They top 32 knots max with Kad 44s, and 35/36 with with Kad300.
As for tuning up being on the limits as long as the boat is not over weight to the engines and you are at 80-90% load on her it is not problem.
With Kad300 a Targa 40 will be at 80/85% load at 3100 rpm at about 27 knots cruise speed. Total consumption of about 70/80 litres per hour.

I agree. KAD44/300 on a Targa 40 is perfectly acceptable for most owners (apart from speed freaks). Will also be cheaper to buy and have more space around the engines for maintenance..

 

[oldgit]

Also have doubts about the" spares will be hard to find" to find argument against the KAD compared to the "D" series .
Volvo Penta and after market suppliers still provide bits for an engine first introduced in 1988 well over 40 years ago ,the 41, many parts which are common to the 40 series introduced in 1977.
Hope yet for KAD owners. ?

 

[bluetooth]

Fuel efficiancy claims .
Lots of stuff regards "D" series and much older engines virtually nothing on KAD. 300.



Even the out of the stone age Yanmar 300 hp is easy to find.
YANMAR.

Here's the KAD300 data graph:

 

[oldgit]

Think did spot that one but that was in specific boat Windy ? and wanted to directly compare figuires on a dynometer etc.

 

[[165042]]

Early D6s had a lot of issues - end caps leaking - heat exchanger failure - oil cooler leaks etc. Speak to SAL Marine about written off engines they've replaced. At the very least get a full engine survey with oil samples etc if you're looking at a boat around 2006.