Repower sunseeker

[prb]

I am looking to repower a Portofino 31. It currently has twin 270 VP petrols which give a fast cruise of 30-32 kts and nearly 40 kts flat out. I want to switch to diesels but retain this level of performance. The new D series are probably out of the question on cost grounds so I am looking at the following second hand;
AD41 (200hp), KAD42/3 (230hp) or KAD44(260hp). I suspect the 44's would do the job (but the difficulty may be finding some). These boats were originally fitted with the AD 41s and reports are that max speed is only likely to be 34/35kts. Does anyone have any knowledge of how the boat is likely to perform with a pair of 230's? Also, is the s/chgr / turbo really as noisy as the write-ups for the new D series engines make out?

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[[2068]]

I would steer clear of the 42's, and go for the 43's or 44's. Although your top speed might not be exactly where it was before, your fast cruise speed should be achievable. The 44's with the 24 valve heads and EDC will probably give better performance and better fuel consumption, but check that the valve clearances have been adjusted as specced...

The blower is a bit whiny when it kicks in - 1600rpm - 2600rpms, but then once past 2600rpms it disengages, and it all goes quiet again. You can get in situations where it engages/disengages continuously, but you soon learn to avoid those...

dave.

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[rlw]

Just out of interest. Why stay clear from the KAD 42? I currently have a Portofino with diesels and want to upgrade next year and the KAD 42's I believe are found in the early Martinique's or other similar boarts made early 1990's.

I'd be very interested to hear if there are any pitfalls to watch out for.

Regards

Rob


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[[2068]]

I'm sure there are many satisfied KAD42 owners out there.

It's just that compared to other VP engines, there seem to be more problems such as piston failures (some total, some partial with excessive crankcase pressure), some possibly related to overpropping/overloading, some not.

These issues seem to have been sorted with the later 43's and 44's, although for an example of what can happen to a 44 if you don't check the valve clearances, look at MBM's previous "Calm Voyager" (dropped a valve, crunch, ouch...)

dave.

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[Col]

Earlier Martiniques had AD41's

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[rlw]

Coll,

Correct, I meant 41's. Your pics seem to suggest you have a 38.
If with 41's do you find them powerfull enough? What "real" to speed to you get from them. I have been told a few things by someone trying to sell me one that I don't believe.

Rob

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[Col]

Yep Martinique 38. With clean bottom and ideal conditions I have seen 31knts. Boat is 7 1/2 tons dry, prob 9 1/4 tons with full fuel, water, provisions, and kit + passengers.

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