Re-engine.. Compact Diesel Sterndrive

Fire99

Fire99

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Evening everyone,

Further to the post Jezbanks raised regarding the merits of petrol or diesel engines in a small (23-25ft) sports cruiser, i've been considering the idea of re-engining my V8 petrol motorcruiser.

This is just a fact finding exercise at the moment but i'd be interested in peoples ideas.

My 23ft Sports Motor Cruiser currently has a 200hp Volvo V8 Petrol (5.0 litre Aq200) which gives around 30kts when all odds are even.
From the information i've downloaded i think this engine weighs around 450kg all in.. (i'll stand corrected if wrong).

Now what would people recommend as a diesel replacement. The obvious one that springs to mind is the Volvo D4 which they do one rated around 200hp and i think is a similar weight.
Then i've seen the D3 which i believe is 170hp but i would guess would be a little underpowered.

I've also seen the odd Nanni Diesel rated at similar power outputs.

Does anyone know of the merits (or not) of these engines or any alternatives?

Also with the extra torque of a Turbo Diesel i would guess cruising i could get away with a little less hp?

Anyway as i say its just a bit of fact finding at the mo but any thoughts in the twilight hour would be appreciated.

regards,

Nik
 
Lombardini Marine 194JMT 4cyl 160hp or 245JMT 5 cyl 200hp, both available to fit VP outdrive or complete with new Merc leg if you prefer.

Have an interesting article about these, similar size boat, VP V8 out and 245JMT in, can email it to you if you want a read.
 
First. Does the engine need replacing??

Second. What do you want the boat to do??

Is exeleration and max speed important.

Or do you just want to cruise for miles.

Cant see that it's worth the trouble, unless there are other conciderations.
 
Hi Haydn,

Well yep you have a point. And on paper it isn't really worth the trouble.
The engine seems to be in pretty good condition (though i guess i could get a few pennies for it if i sold it)

The main considerations are fast cruising 22-25kts+ with 30kts achievable but with significantly increased cruising range and greater fuel availability at Marinas.

Financially it is borderline as i havent seen anything i'd rather have even at 10-12k more than i paid for mine.
And i rather like my little boat. She's been fitted out inside really nicely. Just would be nice to cruise alot further without fitting a ludicrously big fuel tank.
Or perhaps a larger fuel tank would be the better option.. as i say open to suggestions..

Nik
 
Sound to me that, like me. You will soon need a bigger boat. For bigger range. Range is not only about errr bigger range, but also about what you got left when got there. You need more water, more chain, more ropes. More just about everything. Dont know where your based, but longer cruising comes up with a whole host of other things you need. Umm we started with a 21ft'er, petrol V8 with 20 gallon fuel tank. To cruise half the british isles. Failed miserably. /forums/images/graemlins/laugh.gif
 
We changed our mercruiser V8 for a styer 260hp diesel for fuel availability reasons. Range went from 170 to 300 miles. styre is very light & sporty. Had to move fuel tank forward a couple of inches though, & styre not cheap. See lancing marine /forums/images/graemlins/smile.gif
 
Think in MBM this month there's an article about Mercruiser bringing out a new engine to replace the 1.7TD think it was a 2.0 litre which would be tuned from 115 up to 200hp.. or was it 150hp max also there's a newer version of a bigger engine but I can't remember much about that!!

Regarding your comments about Turbo's and torque it will help for getting up on the plane but once your there you still need to have enough power to maintain your cruising speed so if your looking to maintain the performance you get from 200hp I would drop much below that otherwise you may be disappointed!! Although a duo prop may help a bit!

Another engine is the Yanmar 220 not sure on weight though...
 
I swapped a 230hp V8 petrol in a 24ft sportscruiser for a Volvo KAD32 170hp. Top speed now is 30 knots with clean bum. Before it would have made a couple of knots more.

There are lots of choices now in the compact diesel market. The D4, as someone has already pointed out, is a very heavy engine although physically around the same size as a V8. The 190hp D3 would be good, as would the new cummins mercruiser 2.8ltr 230hp. Styer, FNM, Nanni, Lombardini and Yanmar all make engines of suitable power and dimensions. Yamaha would also be worth considering with their new TRP range with Hydradrive, specifically the 4cyl 165hp ME370.
 
weight is a good point. Sticking a few hundred kilos right at the back of your boat probably isnt quite what the deisgners had in mind. Someone "in the know" once said to me ,volvo,merc yanmar.. dont bother with the rest. Grossly unfair, perhaps, but i ve always though if you are going for a fancy compr+turbo arrangement, maybe its best. If its just a chugger you need , probably less valid.
Seems alot of trouble, with uncertain outcome. Why not just buy more petrol!
 
In my opinion I would say don't do it, sell the boat and buy one with a diesel. Unless you can fit a good secondhand engine an DIY, it will be a big financial mistake.
My own boat came recently converted to diesel with a receipt for £27K, the previous owner had only done 69hrs in 3 years on them, he took a massive hit.
I saw a lot of similar cases when I was looking as well, with all the red diesel paranoia around at the moment you could probably find a bargain.
 
Get yourself dowm to Lancing Maring and get a Crusaer V8 diesel fitted, perfect replacement of existing and coupled up to your existing Volvo leg.
 
That's gonna be a heavy old lump, check the weight first. Also when going petrol to diesel you need to consider the gearing in the leg if trying to use existing outdrive. Petrol usualy rev much higher than diesels.
 
Yes maybe higher than some others but still not as high as a V8 petrol. The new Steyr 256 (250hp revs to 4500rpm so very close, the 165hp 174 only revs to 4000. Your average V8 will run at 4800rpm. Also there is the additional torque from a diesel that some outdrives designed for perol engines may not be able to deal with. It's just something that needs to be considered but by no means ruled out.
 
Thanks guys for the replies.
Everyone's opinions are right. In many ways it would be far easier to buy another boat however if you really like the boat you have it can be quite hard to part with.

As a matter of interest i think max revs on my aq200 petrol is around 4500rpm

I will have a chat with lancing and coastal and see what sort of money i'm looking at so i can get the full picture.

On that note any idea of approx labour cots of fitting a single Sterndrive lump?

many thanks,

Nik
 
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