Kad 300 v D6 in targa 40

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tamarind

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Whats the advantage of the D6's over the kad 300's? I know that the D6 have more horses but are they a better more reliable unit? Can they be run for a long time at displacement speeds, say 8 knots? As the kads don't because they will run on the compressors.
 
D6 is the latest technology - direct injection and more powerful/smoother than the KADs it replaced. Also a bigger displacement hence no requirement for a supercharger.

I would go for a D6 engined T40 if I could, with the exception of the early 310 units. These had issues surrounding the water strainers and you would need to check the remedial work has been done.

Also, the D6 engined boat gets the later DPH drives. Better than the units on the KAD engines but again with a caveat, make sure the drive trim rubber boots gave been fitted to avoid premature wear on the ram seals. Not an expensive item to fit but best done before launch and if a boat doesn't have them it may indicate you will already have damaged seals.

D6 bust also more efficient and easier to service than the KAD300 boat which has delicate tappits
 
Whitelighter said:
D6 bust also more efficient and easier to service than the KAD300 boat which has delicate tappits
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I wouldn't be put off by the tappets... its a few hour job every 200 hours, no biggie.

What's better about the DPH drives than the DPG?
 
No, if I could only font a KAD300 boat I wouldn't be put off buying it, but given the choice it's a feather in the cap for the D6 boat.

DPH is more efficient as are the nickel bronze props (though you need to make sure your electrolysis protection is good).

There is nothing wrong with the KAD300/Drive set up. It's just older tech
 
Whitelighter said:
D6 is the latest technology - direct injection and more powerful/smoother than the KADs it replaced. Also a bigger displacement hence no requirement for a supercharger.

Er, most D6's on drives have a supercharger (compressor), we see very few boats fitted with the non compressor version. So these will run on the compressor at low speeds same as a KAD 300 which also has direct injection, just not common rail as on a D6.
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spannerman said:
Whitelighter said:
D6 is the latest technology - direct injection and more powerful/smoother than the KADs it replaced. Also a bigger displacement hence no requirement for a supercharger.

Er, most D6's on drives have a supercharger (compressor), we see very few boats fitted with the non compressor version. So these will run on the compressor at low speeds same as a KAD 300 which also has direct injection, just not common rail as on a D6.
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Didn't know that. Fair enough.

Though I would question the op buying a t40 to run a displacement speed. Can't see the point in that myself.
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have no experience with direct comparison you give but we do have with D6 350 on DPX drives and Yanmar 315's on Bravo 1's

The D6 was smoother, quieter, less smokey on start up and had a bucket load more punch than the Yanmars on an identical boat. Better response at all points of the rev range. dont have details on relative consumption as one boat we bought and the other we didnt....

As i say, not a direct comparison but it was a comparison with new tech / old tech.
 
I have KAD300s + DPG + s/s props - goes like a scalded cat and it's a very smooth motor - I have no complaints other than the amount of belt dust they create. (I've had a couple of odd things happen that seem to have been linked to a lack of use over three years prior to my purchase). I wouldn't want to be running the engines with the compressors engaged for long periods of time though - creates noise and lots of belt wear. Not driven a D6 so can't comment, but the DPH drives have a somewhat mixed reputation, and the drive boots don't necessarily fully solve the problem so I've heard.

I would expect the KAD300 boat to be cheaper than D6, and IMO certainly worthy of consideration.
 
For me the KAD 300 were great and apart form the tappets pretty simple, early D6 as said by whitelighter had lots of water sea strainer issue's and even if the mod is done they may well have dosed the engines in LOTS of seawater...... so look very carefully with a good torch for the tell tale white crust of dried on seawater.
 
Clive, the kad 300 would suit your pocket more than the d6.

Ill show you parts service costs next time I see you, the kad300 is the same as your ad41 prices in round figure terms.

The valves need doing every two years and the targa has an excellent engine bay with the dinghy floor out .

The price of the anodes and synthetic drive oil is eye watering compared to the dpe or dpg depending if you had 300 or 44s.

You need to buy what suits our pocket and look at the recent exhaust issues on the d6 sterndrive package.

Also factor in the cost of one d6 injector, also starter motor, an alternator is over twice the price of one for the kad300 , shall I keep going???
 
Listen to VolvoPaul not me but ..... I have a T40 with D6 /310. I used to have a Cranchi with KAD 300. I prefer the D6 as , only one belt per engine - the KAD 300 has lots of belts, dust and in my case used to shed about a belt a year in the most inconvenient places. Also to change the leg anodes you need to remove the prop as it is a ring around the base of the propellors - on a D6 you just reach down with an allen key. My D6 is not supercharged - I did not know any were - maybe the bigger ones. The KAD 300 supercharger does make a bit of a noise, but you cant really hear it unless you want to.

Other than belts neither engine or drive gave a problem.

The D6 has the DPH leg which had the steering ram issue. i have changed mine once so at a guess you need to change these every 3 years or so. I used refurbished RAMs of ebay which were cheap as, but I gather the price from Volvo has now reduced.

The D6 has more modern helm controls - EVC as opposed to its predecessor.

As another poster mentioned there was an issue of the plastic water strainers bursting, and the replacement part has a glass lid. I cannot remember the bill - I will say £100 per side but I really cannot remember.

For me a D6/310 which I would imagine would be easier to sell when you are done with it.
 
tamarind said:
Whats the advantage of the D6's over the kad 300's? I know that the D6 have more horses but are they a better more reliable unit? Can they be run for a long time at displacement speeds, say 8 knots? As the kads don't because they will run on the compressors.
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Specifically answering your Q ,s I would say D6 on balance is less reliable , - limp mode !! ,more electro- twactery to go wrong .Then the " chocolate tea pot" - done to death on the forum - outside steering ram !!
Trolling comp issue - I think you can get an aftermarket kit/ switch thingy to manually turn them off ( both Kad300 and the supercharged variants of the D6 ) if you really bothered ?

In realality D6 as you infer has bags more horses, torque and pops up quicker etc ,
Smoothness ,nothing in it the kad is smooth , not an issue ,
Parts/ service the Kad wins ,especially if you inc un scheduled steering rams ( and associated lift out / down time ) .
Residules D6 over kad , cos it's got more umff.-but it may cost you more to buy as run? Tricky one !
Fuel Eco not sure but " man maths " says 3.6 L Vs 5.5 L , or 285 bhp Vs 310'330' 350'or 370 bhp so go figure ! Producing 370 must burn more fuel than 285 ,( i dunno? ) both seem to run @ 3000 rpm ish ?
If the T 40 is a " lardy" boat for ts size then one might need all the horses/ torque .In which case it's a done deal D6 for this boat ?
8 trouble free years with Kad300 ,s
 
Portofino said:
Fuel Eco not sure but " man maths " says 3.6 L Vs 5.5 L , or 285 bhp Vs 310'330' 350'or 370 bhp so go figure ! Producing 370 must burn more fuel than 285 ,( i dunno? ) both seem to run @ 3000 rpm ish ?
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A couple of years ago we took Vega (Targa 40/D6-350) from Brighton to St Vaast, a run of about 90nm ish. We cruised in company with another Targa 40, with Kad-300's. I can't particularly remember what speed we cruised at, but we were together for the whole crossing. We both started out with full tanks. He needed to get a top up St Vaast in order to be sure of safe range for the return trip; we didn't. So based on that, I'd say that the D6 is more economical than the Kad.

Cheers
Jimmy
 
Yes I agree, but it depends who was following who.

For example if you cruise a D6 350hp at 28 knots it might be more efficent then a KAD300 at same speed. But possible that at lower speeds for example 24 knots the 40 Targa with KAD300s is more efficient.

Given choice I would always prefer a 40 Targa with D6 but as some1 stated it depends on the price.

jimmy_the_builder said:
A couple of years ago we took Vega (Targa 40/D6-350) from Brighton to St Vaast, a run of about 90nm ish. We cruised in company with another Targa 40, with Kad-300's. I can't particularly remember what speed we cruised at, but we were together for the whole crossing. We both started out with full tanks. He needed to get a top up St Vaast in order to be sure of safe range for the return trip; we didn't. So based on that, I'd say that the D6 is more economical than the Kad.

Cheers
Jimmy
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Another consideration is parts availability.
As the years go on, it will eventually get to the point where the older generation of engines become harder to source parts for.
Even now, there are some parts for KAD series engines/drives in the VP catalogue that are "out of stock, out of production", which mean you end up buying a bigger assembly or recon build, whereas D6 is current generation.
 
FlowerPower said:
Another consideration is parts availability.
As the years go on, it will eventually get to the point where the older generation of engines become harder to source parts for.
Even now, there are some parts for KAD series engines/drives in the VP catalogue that are "out of stock, out of production", which mean you end up buying a bigger assembly or recon build, whereas D6 is current generation.
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Well yes and no, ill give you an example on jtb boat he needed a priming pump for the fuel filter, in the parts list it shows it as a separate unit, but buying it was a different story, it now comes as a whole assembly , housing , filters, switch etc over £400!!! Plain stupid. Also you cannot re line or bore the d6 block, it's a new short engine. Pistons and liners are available non vp for the kad 4 and 6 pot engine made by ks in Germany.
 
Thanks guys for all your replies. I was wondering about running either of these engines at displacement speeds for long distance cruising, if time allows you travelling at 8 knots you will get approx 4 times the range out of the tanks. I've recently done a delivery trip on a P64 and doing 9 knots we covered 800 miles on one tank, at 22 knots we only got 240 miles. It's great to have the option to travel at both speeds
 
My boat runs on D6 350's and DPH's , my previous boat ran on KAD 300's and out drives (can't remember which type). I can tell you that the D6's will cost you a lot more in servicing and parts (as Volvopaul) says. The D6's are smoother and more powerful but having run both I think I prefer the relative simplicity of the KAD 300's. With the D6's I find my self waiting for the next thing to go wrong. However, as someone previously mentioned, you will benefit from buying a D6 T40 when it comes to selling it on.
 
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