KAD44, KAD300 OR D6...THAT IS THE QUESTION

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mrgrumpy2

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I have a shortlist of 3 Sealine S38's that I am going to inspect (with a view to buy one) in the next couple of weeks. Suprisingly each one is running different Volvo Diesel engines and I'm wondering if there are any major differences (apart from the Horsepower) and more importantly if there are any known problems or issues with the three engine models. An idea on fuel consumption may also be useful. The three different engine pair choices are KAD44's (260hp)... KAD300's (285hp) or the D6's (310hp). Thanks in advance for your opinions and information. .....Happy New Year!!
 
I think its true to say all Volvos have issues /forums/images/graemlins/grin.gif you idealy should go for the biggest and newest engines, the D series are very powerful, smooth and economical so they will no doubt perform the best. However the older KAD's are simpler and potentialy more sorted, so maybe more reliable.
Really depends on the price and your priorites.
 
Just out of interest, I have a 2003 S38 for sale at £134950 fitted with KAD300s. Be more than happy to show her to you if you are on the South Coast. She is currently out of the water (took her out on the 17 Dec) and is on a hard standing at Eastalnds Boatyard on the Hamble.
 
I have KAD300's to DP-G drives on my 2006 Fairline T34 and have not experienced any problems, but if I had the choice I would probably opt for the 'D' series because they are slightly more powerful and a later model. Fuel consumption I would say around 1.5MPG but this depends on many factors: speed, loading, sea state, fouling and the like!
 
If the price were the same for all three I would go for the D6 engined boat.

Thing is, there is probably a significant difference between the KAD boats and the D6. the D6 is a bigger capacity common rail engine with the latest DPH drives. The KAD44/300 is older technology, with DPS drives.

The KAD set up will use more fuel like for like and will be slower onto the plain and have a lower top speed. Between those boats I don think there is much to choose and I would go for whichever boat is in better condition and has better options/navigation/features as the extra 25Hp from the 300's wont make a huge difference.

FOr the D6, it would be my preference but assuming the boat year is the same, i would only want to pay a £10k premium for the D6s. much more than that and you wont really see the benefits, unless you want to go everywhere at 35 knts!

They all have electronic throttles, but the D6's again have EVC (electronic Vessel Control) which the KADs didnt. This gives you the option of lots of plug in gooodies such as under rev counter computers, extra sensors and real time fuel flow and usage readouts.
 
I would agree with JRB your fuel consumption for the same speed is going to be within a whisker of each other but if the boat with KAD 44's tops at say 32knots and with D6's goes up to say 38knots you will consume condiderably more fuel at 38knots.

All the engines are solid but the D6 will have abetter resale percieved value although it will cost more to service.

The D6 Boat will accelerate like hell compared with the others , much more bottom end grunt and acceleration.
 
IMHO iwould not be worried about engines , but would be looking closely at drives as i have probs with DPH drives after only 9 months and so far not sure if the fixes done by volvo will last after warranty expires , ( steering rams , corroding prop ).
 
The D6 engines are great very smooth and above all very economical. bits to look out for. Steering rams as origionaly fitted can suffer pitting (However if you push with volvo they will probably replace with a new version with gators. Also hydrolic pipes can be delicate so be carefull when washing of if using a power washer. I managed to get a new set of rams from Volvo at no cost however it took a few strongly worded e-mails.

In 2005 Volvo had a bad batch of props ( Bronze) on the D series so check for pitting on the hub at base of blades. If you find this you should have no problem in getting them replaced, as their was a recall.

I have run mine for 600+hours no problems and very happy to date. boat sounds great with a nice hum at speed rather than the feeling of being chased by a couple of London taxis.

One thing to watch out for if you go for the D series is that the Raw water intakes on the front of the legs have very fine holes. I suffered slight overheating until I discovered tiny barnicles growing behind the cover. You need to remove every season and clean well.

One other point is that if you ever have to change an impeller then remove the whole housing in one piece it's nay on imposible to change in situe and getting the seal back well forget it. I changed both impellers in about 45mins once I had worked this out.

I recon the D series will give you about another 5 knots top end and about 20% better economy.

Hope I've helped.
 
[ QUOTE ]
The D6 Boat will accelerate like hell compared with the others , much more bottom end grunt and acceleration.


[/ QUOTE ]

I'm pretty sure that's not true, the KADs have superchargers where as the D's have variable turbos which still needs to spin up to get going. I've not been on a boat who's engines can out accelerate the bigger kad's. They are lightning off the mark.
 
Kevin,

The common rail D6 has far superior AFC control due to having a 3D timing table. Also relativly low Hp for greater swept volume which compensates for the supercharger/turbo set up.
Simple cubes rather than the complex 'solution looking for a problem' air handling on the KAD.

If you download the power/torque curve of the motors D6-310 just shouts I am better than the KAD.
 
The D6's are a piece of cake to service 2 hours max if you have everything lined up, inc all filters and impellor and motor anodes, nearly as easy as a Mercruiser!!
There are no tappets to adjust (hydraulic) which is 3 hrs extra labour on a Kad 300.
I know it needs 20 ltrs of oil as opposed to 9 ltrs for a K300, but the service costs should be about even.
The K300 is a stretched engine delivering 285hp from a 3.6 ltr block, whereas the D6 is using a 5.5 ltr block = less stressed.
I'd go for the D6's if the price is right as the resale value will be better.
There are issues with steering hoses, done about 7 sets now and now in the last 2 weeks I have changed two sets of trim cylinder hoses which is a time consuming job, but Volvo pay for it no questions asked if the engine is in warranty.
Check the hoses for swelling on the rubber clad outer surface, if swollen its usually full of hydraulic fluid and VP will replace them.
 
The D series has a list of serious faults to look out for but once the modification has been carried out you should be fine

Drives
as mentioned above need gators adding to steering

Engine

There has been a recall on the raw water filter as they fail and risk sinking.

Not all will have been changed, you need to check.

Heat exchangers end caps fail, and risk of sinking

Gauges work fine as long as kept dry.

injectors
are temperamental to fuel quality and explode if poor quality fuel is used.
It is expected once the boats get older and tanks of diesel become mixed with old and new diesel the injectors will suffer badly.
(full details of injectors here

The D6 is claimed to be economic, I think Roger Rat gets 2 mpg @ 45 mph, thats about all I find good about it.

NB

This was posted before I read spanner mans post, spannerman knows his stuff, I only know about the few boats I have come accross.
 
[ QUOTE ]
They are lightning off the mark.

[/ QUOTE ]

So are the supercharged D6's /forums/images/graemlins/smile.gif
D6-310/330 is slightly more relaxed in terms of acceleration, in that it doesn't really get going until 2000rpm.
 
Real world example, Fairline Targa 40 with KAD300s vs Fairline Targa 40 with D6's.

D6's boat is a world apart and you can really feel the difference. Even at 35knts open the taps and the boat gives you a little kick in the back as it goes. KADs dont even come close.
 
Another real world example:

Fairline Targa 40 with D6-350's (700hp)
vs
Sealine S28 with KAD32's (340hp)

Both boats pass West Pole travelling West.
D6 powered boat disappears in a haze of blue LED's within a couple of minutes
/forums/images/graemlins/laugh.gif
 
Poor old Mr Grumpy trying to get some real infomation.

All he gets instead in a barrage of undatabased prejudice.

All the feedback I get is that the D4/D6 is doing a great job out there, if it were a lemon would Volvo still be boatbuilders #1 choice. Funny that the guys that fix them quite like the engine.

What I am qualified to comment on is the Bosch fuel system which I do have actual data on. The Volvo D4/6 shares the Bosch CP3 fuel pump and injectors with Cummins, IVECO, MAN and Mercedes Benz just to name a few. CP3 pump and injector production is running at well over 2.5 million engine sets a year, hardly the fragile a trouble prone system portrayed by the dinosaurs here.

If you really want to feel some pain go on to the Barrus stand at the boat show. Enquire about the cost of pump and injectors for Yanmar 6LYA3. Remember they cannot be serviced by regular Bosch/Denso agents.

Sadly prejudice always seems to get in the way of the facts.
 
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