petrol to diesels - but which ones for our Triana

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Freebee

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We have decided that we should like to change our twin aq151 petrols 140 hp for diesels. we have VP 290 outdrives with single prop. We have a planning boat - Triana and would like to keep the HP / Performance up. 2 engines appear safer to SWMBO!

At the boat show we toured all the major engine suppliers and had quotes for a complete swap of engines and drives at prices up to £k40!!! Most said our existing drives would not take the torque of 150 hp turbo diesel. One said they could provide 2 engines to fit our drives but it was still £k20. So I could be in the market for a pair of preowned marine diesels that would fit our drives or be adapted to fit.

As an alternative I am also looking at marinisation kits to convert vehicle engines - the first thing that hits you is most suppliers want to use old pre ecu mechanical injection engines which would be Ford/Isuzu/Peugeot/ VW based - in same cases due to age these are now in short supply and of course would be high mileage. I am not averse to getting the spanners out but I don't want to re invent the wheel or indeed be stuck with a pair of engines under development that will need constant tinkering. Yes i've spoken with Lancing marine.

So what would you do? Have I missed an option, has anybody had experience or going through this same headache???
 
Talk to Mike at Lancing Marine. They used to do ford puma engines at 140hp. He will tell you exactly what you can and can't do with your drives. You are probably still looking at a pretty big bill, but cheaper than the likely quotes you would receive from the likes of VP etc.

The only other problem will be the ratio of the legs and the prop sizes. AQ151 probably rev to around 6000, but even a fast revving diesel is likely to stop at around 4000. You will be able to offset some of this with a prop change, but I suspect you may also need to change the ratio of the legs.

Best bet would be to try and pick up a pair of complete packages. The difficulty is that, while they do occasionally come up in singles, you will be hard pushed to find a pair. Try someone like coastal rides and see if they have anything suitable. Alternatively, fill in the holes in the transom and stick one big diesel in. Around 300hp should do it :D


Edit: just checked, and the max rev range for the 151 is between 4800 and 5500 rpm, so maybe not quite as bad as I thought if you get get a fast running diesel.
 
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Cough, Cough....... Yes you can mate a Lancing 140hp diesel to a 290 SP drive.
Will need 21"pitch LONG HUB props+ an extra 2" of pitch and 1" of cupping (Steel Developments)
Aim is to get ~ 15psi boost and ~4000 revs at WOT.
 
How many hours a year does your boat do ?. If it does the average 50 hours per annum and going to assume it probably does less...a lot less, then you are going to go to a great deal of time,trouble and expence in order to achieve what. ? If the boat is fairly reliable why not just enjoy what you have. Have great respect for Lancing and have bought stuff from them but old van engine conversions are not always trouble free especially taking into account adapting the drive system. In order not to stress the outdrives, you could end up with slower boat, consider the extra weigh of diesel engine blocks. Doubt you will ever see your money back and the conversion may well deter future buyers who would prefer an original boat that has not been messed around with. ? To sum up, if you were doing high hours long distance cruising and money is no object then why not but if its merely because of lugging a few gallons of petrol around on the odd weekend, then leave well alone. You may also not be impressed with a pair of smelly noisy old lumps smokely vibrating away under the deck. :)
 
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Freebee said:
We have decided that we should like to change our twin aq151 petrols 140 hp
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Why Mike?

If its the fuel cost then no point, you'll never get cost of the job back.

Viking had a pair of CMD300 diesels, far too much weight, so they converted to a single one. The one the was left over went in Pete's Lady Emma.

Lady Emma did have a pair of Mercruiser V6 4.3ltr petrols, fuel injected, went like a rocket, 47 knots, as above, now has the single CMD300

Le Scarron did have twin petrols like yours I think, switched to a single 454 Magnum, but now has a bigger V8.

Barry S has bought a twin petrol set up for his boat, White Egret, I think they are the V6 4.3ltr Mercruiser.

I see your engines are old and cranky and you might want something newer, I'd look for a pair of those V6 4.3ltr Mercruisers and duoprop legs.
 
oldgit said:
Doubt you will ever see your money back and the conversion may well deter future buyers who would prefer an original boat that has not been messed around with
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Positively +1, 'cept that I'd replace "doubt" with "no way".
Besides, diesels are plain wrong on a boat like that, which benefits from the greater rpm range of petrol engines - not to mention weight: if there's one thing Levi would have considered, it's less weight, rather than more power.
 
How about a used d4 for £7.5k. Would need an outdrive however.

http://www.marineenterprisesltd.co.uk/

KAD300 for 8.5k with 320hrs:

https://coastalrides.co.uk/index.php?route=product/product&product_id=21462&sort=p.price&order=DESC

Weight comparison vs your current motors and drives would be necessary but I cannot see how a single diesel like the above would be too much heavier than two 151's. Fit within the current engine bay would be more of a question (for the KAD300?). For a diesel conversion it has to be a single engine to be viable imo, maybe investigate an auxiliary engine for breakdowns?

Otherwise leave as is and swallow the fuel costs unfortunately, or buy one that has had the conversion done already.
 
burgundyben said:
Why Mike?

If its the fuel cost then no point, you'll never get cost of the job back.

Viking had a pair of CMD300 diesels, far too much weight, so they converted to a single one. The one the was left over went in Pete's Lady Emma.

Lady Emma did have a pair of Mercruiser V6 4.3ltr petrols, fuel injected, went like a rocket, 47 knots, as above, now has the single CMD300

Le Scarron did have twin petrols like yours I think, switched to a single 454 Magnum, but now has a bigger V8.

Barry S has bought a twin petrol set up for his boat, White Egret, I think they are the V6 4.3ltr Mercruiser.

I see your engines are old and cranky and you might want something newer, I'd look for a pair of those V6 4.3ltr Mercruisers and duoprop legs.
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Mike, you know my thoughts and I understand your dilemma completely but for the record, knowing all of these boats well and having undertaken several evolutions with Le Scarron I would concur with most of the advice above.

The petrol vs diesel debate on the face of it is all about running cost vs cost to re-engine. New machinery is out of the question as throwing £30k plus at the boat would be pointless as in reality your annual fuel savings are likely to be about £1k at very best.

On that basis sticking with petrol is the only sensible answer unless you strike very very lucky and find a pair of very cheap small, lightweight modern diesels. With the Triana Mapism is correct, weight is your enemy - they do not respond well to any more than 600kgs of machinery in the stern.

Also do not underestimate the cost and effort involved in changing machinery, assembling a package of the correct engine + drive plate + flywheel cover + drive shield + outdrive leg + props [ratios are crucial]. is not simple. One of the other owners has a brand new pair of Mercruiser 135hp petrols with Alpha 1 drives in crates ready to swap out his original transom hung Volvo 120s and although is would appear to be a straight swap it will be a complex project in itself.

I would concentrate your efforts on updating your fuel tank first and foremost.

In the meantime keep your ear to the ground for replacement engines, a pair of good cost effective petrols complete with the correct drives as a package is much more likely to pop up.

The only thing you need to add to any one of Sonny's sublime designs is;- lightness, power and simplicity

P.
 
One thing you may have to consider is the practicalities of actually fitting the replacement engines. For instance the AQ151’s are straight 4’s and have a relatively small footprint. How much room have you in the engine compartment? Many of the replacement engines are wider or higher and may not actually physically fit. I know that the AQ151’s are quite old now and reliability maybe an issue as well as replacement parts like exhaust manifolds etc. However stainless steel manifolds are available now with considerable weight savings and “apparently” up to 10% more efficient. A good motor engineering shop can often overhaul these engines for a fraction of the price of new engines. I am not sure the availability of refurbished KAD32’s but that maybe nearest to your current engines without breaking the bank.
 
1st post - Woohoo!:cool:
We are doing something similar on our Fairline Sunfury.
I have looked at all the permutations and the only real economic answer is to convert to a single petrol.
If you have a boat in good nick, its just about worth it.
We are going for the best Fairline Sunfury award and hope to surprise a few people with 35knts:encouragement:
 
tico said:
@LBR...... Converted a Sunfury to diesel a few years ago very sucessfully using 2x engines from Mike at Lancing. Google 'Fairline Sunfury Bermuda' and it should throw up something.
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Tico, will do - Nice boat!

I have spoken to LM and the availability of the small diesels isn't the same since Ford have stopped making the engine that they used.
So the possibilities of having 2 of any engine is limited unless we go for used. Which, we have 2 of them already! :cool:

We want turn key reliability with top performance alongside efficiency. 3-350hp on a duoprop will do that.
All the suppliers and fitters have pretty much agreed with our research.

I think twin drives on small boats is outdated. Engine tech has moved on, particularly in the petrol world.

Diesel doesn't work for us. Horses for courses as they say. Plus as a self employed contractor, relying on a tax break is something that only ends in tears!
 
I have seen a Fairline Targa 27 with 2 new small block V8’s Vortec engines based on the GM Marine Engine. Maybe worth looking into as some of the auxiliary parts like steering pump etc could transfer. You can probably use the existing outdrive but worth checking first. I think these are available on Auction Sites!!! I have no experience however so it may be worth getting feedback if possible.
 
I'm just going to say it, would it be absolute sacrilege to repower a classic like a Triana with a single 300hp verado on a pod, assuming good quality work etc. Lower purchase cost (guess), lower fuel consumption then two carb'ed engines, cheaper servicing, better reliability from a new engine and the ability to lift most of the engine from the water.

Maybe some concern about moving the c.o.g aft Vs. the weight of the two existion i/o's?
 
Ferris,

I reckon it would be a first! Definitely pimp my ride territory.

New for new, conversion for a 300hp Verado would be the same price as a single 300hp inboard.
 
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