KAD 42 reliability and rebuild costs?

[JakeMM]

I'm considering buying an old Sunseeker with either twin KAD 41's, or twin KAD 42's - more than likely the 42's.

I was just wondering a few things.

1) How much is the yearly cost to maintain these, and the bits that go in the water (outdrives, sterndrives? - not sure what they're called!).

2) How reliable are the KAD 42's (and 41's) assuming yearly maintenance is kept up?

3) Should things go wrong, how much would a full rebuild cost for both engines? (just want to know as a worst case scenario!)

Thanks!

 

[simonfraser]

either buy it v cheap or with lots of bills for maintenance
twin whatevers is 2x the cost .....

sterndrives and associated gear rot in salt water and get affected by barnies

 

[BruceK]

I'm considering buying an old Sunseeker with either twin KAD 41's, or twin KAD 42's - more than likely the 42's.

I was just wondering a few things.

1) How much is the yearly cost to maintain these, and the bits that go in the water (outdrives, sterndrives? - not sure what they're called!).

2) How reliable are the KAD 42's (and 41's) assuming yearly maintenance is kept up?

3) Should things go wrong, how much would a full rebuild cost for both engines? (just want to know as a worst case scenario!)

Thanks!

1) about 1k for twin engine and add another for outdrives. 2k is plenty for general maintenance.
2) Very, extremely, excellent. Provided you keep them in top condition which is easy because they are as simple an engine as you can get.
3) rebuild for the engine is about 5k for the kit IIRC. However dont let that fool you, it's not the engines that are going to give you issues it's the ancilliaries and like all boat engines they can be darn expensive. 3.5k for supercharger, same again for a heat exchanger etc etc. Put in the maintenance and keep on top of it and they will last a very long time. Dont and they will last a very short time.

 

[fred247]

I'm considering buying an old Sunseeker with either twin KAD 41's, or twin KAD 42's - more than likely the 42's.

I was just wondering a few things.

1) How much is the yearly cost to maintain these, and the bits that go in the water (outdrives, sterndrives? - not sure what they're called!).

2) How reliable are the KAD 42's (and 41's) assuming yearly maintenance is kept up?

3) Should things go wrong, how much would a full rebuild cost for both engines? (just want to know as a worst case scenario!)

Thanks!

1. Engines 300 - 600 depending who does the work, outdrives about the same, general maintenance
2. Very
3. 20k
Thats the answer to your questions, but there are so many variables that effect these answers, biggest variable is have they been maintained during their previous life, good clean engines and drives give an indication to overall condition. where as the boat spent its life, a sea boat could well have been thrashed!

 

[JakeMM]

Many thanks for all the replies, that’s very useful information, and this all sounds positive and doable!

 

[oldgit]

a sea boat could well have been thrashed!

Diesels like to be hot and " thrashed".

Worn out rarely is given as the cause of death on any diesel engine autopsy.
Beware the low hours, low use, never gets hot engine, quietly corroding away from within.
Bet you a whole dollar that boats kept on non tidal waters which have spent their entire lives creeping around at 5 knots on short trips out , will be more prone to problems than your average seaboat.

Folks with no handy riverbank to drift across too, tend to take a much greater interest in maintenance as well for some reason.

 

[fred247]

Diesels like to be hot and " thrashed".

Worn out rarely is given as the cause of death on any diesel engine autopsy.
Beware the low hours, low use, never gets hot engine, quietly corroding away from within.
Bet you a whole dollar that boats kept on non tidal waters which have spent their entire lives creeping around at 5 knots on short trips out , will be more prone to problems than your average seaboat

But not from cold and not at WHO all day long

 

[DavidJ]

With the current supply problems of ECU’s for KAD44’s 300‘s etc I think KAD42’s and 43’s may well become an engine of choice In the older boat market

 

[oldgit]

But not from cold and not at WHO all day long

To split some hairs ................
most leisure Boats will have plenty of time to get from cold to warm up the oil. Faffing about after start up ,checking cooling water exiting boat, oil pressures / volts up to spec, undoing shore power,untying mooring lines, getting out of berth, tootling around to marina entrance / harbour wall or in our case the 3 or 4 miles to the end of the speed limit.
Then flat out......Naa.. likely a quick check to ensure no nearbye vessels are going to come cropper due to your wash and then push the throttles up till on the plane and then ease back to fast cruise.
Most will not be going anywhere at WOT other than the last 5 mins on the way back, just to check if the old girl can still pick her skirts up and if something does fall off , its only five minites from home.
Mebbe that just me.

 

[ontheplane]

But not from cold and not at WHO all day long

I don’t know anyone who goes to sea (or inland for that matter) who thrashes their engine from cold.

I never untie my lines until the gauge has moved off the cold stop, and then you usually have 10 min of 4kts or so travelling to get to unrestricted water.

Most people never stay at max revs for more than a couple of minutes.

I’m with the others, hard use better - seen plenty of “bought boat from Thames, won’t go above 1500rpm”.

Never seen an “engine worn out from over use” thread.

 

[Momac]

I never untie my lines until the gauge has moved off the cold stop.........

Not sure this entirely necessary . The following link is about petrol engined cars but I expect may apply to any engine.
No, You Probably Don't Need to Warm Up Your Car Before Driving It

.

 

[Greg2]

Not sure this entirely necessary . The following link is about petrol engined cars but I expect may apply to any engine.

No, You Probably Don't Need to Warm Up Your Car Before Driving It

I have always understood that warming diesels on the boat is unnecessary - pretty sure it has been covered on here in the past. We start up when we are about ready to slip the lines - check the raw water flows and then go. Always stick to displacement speed until temps are starting to register on the gauges though.

 

[ontheplane]

Old habit from when I had an old Volvo Penta 141 which didn’t have a choke, so had to run it at about 1300 - 1800 rpm until it got warm or it would stall. So I always warm the engine before slipping my lines - it’s certainly not “necessary”...

 

[Portofino]

MAN manual suggests wait until the jacket temp reaches 60 degrees before opening up .
Its easy to do just push a bow wave below turbo spool up rpm around 1400 with mine .
Once the magic 60 appears then i spool then up and away I go .