KAD vs D4

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Andyandbec

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Sorry if this has been asked recently, but I couldn't find any thread less than ten years old.
The boats we're looking at purchasing are generally early-mid 2000's so we have a choice of KADs or D4s. We're looking at stuff with twins.
What are the pros and cons of each now?
Is there a clear choice?
With two similar boats around £100k, one with KAD43, the other D4 260 would you pay much more for the D4?
Thanks
 
If the price difference is small , and both boats are well maintained, I'd go d4, just because the d series engines are still in production by Volvo and are likely to be supported for much longer than kads.

D series are a decent engine, smooth (for a diesel), fuel efficient, no smoke, reliable.
 
D-Series Advantages: still in production, less smoke, quieter, slightly more economical, easy shifting and throttles.
Disadvantages: possibility of getting a £2700 bill if a PCU fails, cooling system can require de-scaling.
 
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I guess because I’ve got KAD43’s I’ll give a vote for them because:
simple just 2 valves per head easy to service
No parts problem I’ve found
No electronics
Mine don’t smoke.

However the KAD43 will be 20 years old. Will need new turbos if they haven’t been replaced.
My cable throttles need a complete sort out. Check smoothness
 
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KAD43's will be easier to maintain by a non VP and parts will be cheaper. Rebuild kits are readily availale too if it ever comes to that.

I'm not sure all D4's are the same. I would expect the early D4's to have many parts that are different to the latest engines.

Also worth considering the outdrives. KAD43 will have DPE's which are pretty bullet proof and don't have the troublesome steering rams that later drives have.

I'd expect at least a £10k premium for a D4 engine boat.
 
D4's are reported to be economical on fuel .
But given two boats equally well kept and both 20 years old boat it would be the kad43 for me on the basis of greater robustness and lack of ecu's . If the kad43 boat was £10k cheaper than the D4 boat that would be a bonus.
I think the kad43 was one of the best engines put together by Volvo Penta.
 
D4, definitely. It's a bit like comparing a modern diesel car with a 20 year old Peugeot diesel. The latter will do the job, but technology has moved on significantly.
 
D4 sounds like a tractor , very harsh .
The KAD a very smooth 6 cylinder engine with not much in the line of electrical components to make it run , as said a simple engine to maintain even diy for some tasks.
I’ work on both and whilst I’ve not had a boat for 6 years now I still wouldn’t touch a D4/6 if I came back to the scene.
 
volvopaul said:
D4 sounds like a tractor , very harsh .
The KAD a very smooth 6 cylinder engine with not much in the line of electrical components to make it run , as said a simple engine to maintain even diy for some tasks.
I’ work on both and whilst I’ve not had a boat for 6 years now I still wouldn’t touch a D4/6 if I came back to the scene.
Click to expand...
Thanks Paul,
How about the KAD44?
 
Andyandbec said:
Thanks Paul,
How about the KAD44?
Click to expand...

Comments about KAD43 mostly apply to KAD44, but it has EDC which is good in the sense that “electronics are a good thing when they work“ and a bad thing in that it’s one more thing to go wrong.
KAD44 also has the 24 valve head where the valve clearances need to be correct.
And its power output is at the upper end of what a DP-E drive can handle.

But that shouldn’t put you off ... what’s more important is actual condition and whether it has been maintained properly, and less about what could theoretically could go wrong.
 
KAD43 gets my vote for all the reasons above. As VP once said, only thing that will stop them is a lack of fuel or air. If the engine has been looked after they are reliable workhoses that epitomises the principal of KISS. I happily work on mine in confidence, but if I raise the bonet of my Land Rover I just break down and cry while waiving the plastic.
 
KAD43 for me, nice and simple no electronics still lusty enough to punt our Leader 805 to 31knts whilst still being fairly economical
 
volvopaul said:
D4 sounds like a tractor , very harsh .
The KAD a very smooth 6 cylinder engine with not much in the line of electrical components to make it run , as said a simple engine to maintain even diy for some tasks.
I’ work on both and whilst I’ve not had a boat for 6 years now I still wouldn’t touch a D4/6 if I came back to the scene.
Click to expand...

Twin KAD32s sound like two tractors trying to reproduce and make another KAD32, very harsh.
D4-260 sounds like a Bus going up a hill. It's not a great sound, but it's not terrible.
KAD six cylinder or D6 have the more characterful straight six sound, and are a bit smoother.

D4-260s ...
 
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SC35 said:
KAD32, very harsh.
Click to expand...
While I agree a six cylinder is always going to be smoother I am quite happy with my twin kad32's. They will balance nicely at low revs and at fast speed I have no complaints. You would never know they were only 4 cylinders at 3000rpm.
I do have a flybridge so the engine noise is less intrusive than a sports cruiser.

Reading on this forum any Volvo Penta engine with an ECU is a big risk of not only a big bill for an ECU but also a risk of no ECU being available.

But for a non ecu engine the reliance on Volvo Penta is considerably reduced.
 
MartynG said:
D4's are reported to be economical on fuel .
But given two boats equally well kept and both 20 years old boat it would be the kad43 for me on the basis of greater robustness and lack of ecu's . If the kad43 boat was £10k cheaper than the D4 boat that would be a bonus.
I think the kad43 was one of the best engines put together by Volvo Penta.
Click to expand...

I would go for the KAD because it uses older tech than the D4's. Newer engines scare me because the little brain in them likes to tell you something is up which is always worrying when sometimes it is not. I think they have a connection to Volvo HQ to keep the service income coming in :)
 
ari said:
D4, definitely. It's a bit like comparing a modern diesel car with a 20 year old Peugeot diesel. The latter will do the job, but technology has moved on significantly.
Click to expand...

Yup Moved on indeed but it is for the better ?
 
volvopaul said:
D4 sounds like a tractor , very harsh .
The KAD a very smooth 6 cylinder engine with not much in the line of electrical components to make it run , as said a simple engine to maintain even diy for some tasks.
I’ work on both and whilst I’ve not had a boat for 6 years now I still wouldn’t touch a D4/6 if I came back to the scene.
Click to expand...

Now given who has posted that. I think you have your answer
 
BruceK said:
KAD43 gets my vote for all the reasons above. As VP once said, only thing that will stop them is a lack of fuel or air. If the engine has been looked after they are reliable workhoses that epitomises the principal of KISS. I happily work on mine in confidence, but if I raise the bonet of my Land Rover I just break down and cry while waiving the plastic.
Click to expand...

Old Bruce has got that spot on.......
 
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