Replaced BUKH DV20 with Beta, BUKH..... or maybe even Nanni or Yanmar?

[aidancoughlan]

I've got a Westerly with a 23-year old Bukh DV20. We've had it a couple of seasons, and while it has been generally reliable it takes *ages* to start from cold, leaks oil, and doesnt seem to push the boat well into a seaway (although at full tilt in flat water it pops along at 5.5-6 knots). A local marine engineer has suggested that there is no compression (the flywheel apparently rotates too easily by hand). The water passages are filling with salt deposits (a job i've left on the long finger since last winter). Since we hope to start venturing further afield, possibly involving the occasional long passage under engine we have been thinking of re-powering this season....

options are
(a) Rebuild existing Bukh DV20.
+ cheaper (off-the-top-of-the head quote for 3-3.5k from local engineer to do strip, replace seals & gaskets,rebore block with over-sized pistons, cylinder head overhaul, pump & injector overhaul (chain & seals in water pump).
Not sure how familiar he is with Bukh parts prices though.
- still end up with a 23-year old engine.

(b) BUKH DV24 - 24hp direct drop-in replacement, but a bit more expensive than other options: comes to €7,070 delivered to Dublin.
- It is a physically huge/heavy engine
- costs more than others
- sometimes criticised for being outdated
- parts are expensive.
- hard to access - fills every inch of my engine bay
- no dealer in Ireland
- I've been told (rightly or wrongly) that BUKHs tend not to push the boat very well in a seaway, because of the low revving: is this possibly true ?... would it not be the same as any other 20hp given the right prop?
+ but with a v.good reliability reputation
+ can be hand-started
+ I've heard that the new DV24 starts down to -15degrees celcius without heating.
+ should be a simple installation ...
I suppose 1-day of an engineers time should drop it in (or maybe I can rope in a couple of mates that have done their own engine before)

(c) Beta 25hp - cost €5,000 ..... €7,500 **delivered and fully installed** - ie. just marginally more than the DV24 delivered price.
+ smaller
+ "modern"
+ cheaper parts
+ easily accessible (plenty of room) & easy to service.
+ good dealer network
+ lighter (improve sailing performance?)
+ cheaper
+ good reputation, though not as 'legendary' as the Bukh afaik.
- requires lots of messing about with existing engine bearers etc.
but
+ Beta manufacture (for around £150 I think) special adapters to simplify installation on to the old engine mounts : as long as I measure and fill the form to 1mm tolerance.


(d) Nanni 21hp - €7,000 **delivered and fully installed**
similar pros/cons to Beta, except they dont manufacture the special feet.
the Nannni is not as well represented locally as Beta I think.

I havnt had responses from a Yanmar dealer yet....


So, based on this initial idea of where I am, any comments or suggestions ?

If you were rebuilding a DV20 with a view to keeping the boat for 5-7 years what would you budget to replace in order to have a completely reliable engine for foreseeable future? If I go down this road I'd like tobe able to get specific about exactly what work will he do, what will be replaced etc.
If you were replacing, would you go Bukh or Beta/Nanni ? Any major differences between Beta and Nanni? (both are Kubota based).


Has anybody done a self-install of either a direct (same mounts & size) BUKH replacement, or
Has anybody done a Beta install using the adapter feet for their existing engine mounts - how easy was it to install ?

I've only basic mechanical skills - I've learned to service my Bukh for the last 3 years, replaced engine wiring/panel/starter motor etc. without prior knowledge - but is it feasible for me to self-install one of these ?

Any other factors to influence decision ?

 

[PembrokeshirePromise]

Suspect you will get people saying rebuild your "proper marine" Bukh.

When faces with similar decision last year I replaced volvo MD11C with Beta 28 (kept the old sail drive). Beta pressed a new drive plate onto the existing sail drive and made mounts to fit my existing engine beds.

To be honest they made the mounts the wrong size first time - but to give them credit - they were very embarassed and apologetic about it. Spoke to them on the Mon - and replacement (correctly sized) had been made and delivered by Wed !

Fitting was pretty easy (or as easy as moving heavy lumps of metal into confined spaces can be !) - and the odd question I had during / post install has always been helpfully answered - I'm happy with the decision we took.

Don't underestimate the time and fiddle with all the engine connectiosn though (exhaust, diesel, water electric ets - chances are nothing quite fits !)

 

[30boat]

I have rebuilt two Bukh 20s.One for myself and another for a friend.After the rebuild,Both leaked at the crankshaft seal behind the flywheel.On one the injectors proved impossible to keep tight.Both started and ran reliably.In the end I ditched the Bukh in my boat and went for a Beta DB722 that I got from Steve Birch.Much better engine in my opinion.Smaller ,modern and economical.I did the installation myself and the whole deal cost a lot less than £7000.Delivery to Portugal included.Part of the 100kg or so saved in weight went to sound insulation .
In my opinion Bukhs are archaic designs and being raw water cooled(mostly) can give problems after 20 odd years even after a costly rebuild.
Do you really need a 25hp engine?
By the way ,my friend also got a Beta from Steve.

 

[aidancoughlan]

Hi folks.. .thanks for the responses.

[ QUOTE ]
Do you really need a 25hp engine?

[/ QUOTE ]
well, i'm not sure actually. I occasionally find I'd like a little more push than the DV20 gives me (especially uphill agianst the sea)- I'm not sure if thats because of lack of compresison or what. It was the Beta agent who suggested the 25hp version instead of the 20hp Beta (its only €500 euro more - so I dont mind paying it in the hope of some extra grunt when needed if there's no major disadvantage). I know there is a limit to hull speed and too much power is wasted - but is 25hp too much for a 27ft boat? (which weighs around 3.5 tons as far as I know)

 

[roly_voya]

Recently replaced a similar age Volvo with a new Beta, in my case there was no option as parts for the Volvo where unavailable but even if that had not been the case I would have still done it. Reasons are firstly wanted to increase engine power to improve performance in adverse conditions. Secondly if I was going to spend a large sum on the engine doing up the old one would not do anything for the value of the boat, as you say its still an old engine wheras replacing it with a new one adds almost as much to the value as you spend on the engine.

The piont you make about BUKH's not pushing the boat because they are low reving is wrong. Lower revs on a larger prop will give a more efficient drive with more power in the water. The problem is that because the BUKH is a very large heavy block for its power so its difficult to fit a powerful enough unit in a yacht. You need about 5-6hp per ton with a big slow turning prop. I got this using a beta 37 giving 3000rpm to an 18x10 prop with a 6.5ton boat and it works perfectly. Its also smaller, lighter and quiter than the volvo was.

I didn't go with the custom feet as I needed to fit new engine beds, the old ones where not wide enough to accomadate the sump. You can try to get the new engine to fit to the old installation but if thats also 23yrs old might be easier and better to strip it all out and do a complete refit. One big advatage with the Beta is all the service parts are very accessible, I also fitterd the remote oil filter which made it much easier to change. Reckon I spent about 50% of the engine cost on fitting and updating ancillaries including electrics.

 

[ianc1200]

Just from my limited experience, I put a Nanni 62hp in my boat, a friend a Beta 43hp in his, both about 5/6 years ago. Beta very good in responding to problems/spares, Peachments (who are main Nanni people in UK) slow, don't respond, send wrong bits out etc. Wish I'd had the Beta instead.

IanC

 

[vyv_cox]

I replaced a Bukh 20 with a Yanmar 27. A big advantage of this choice (apart from more power and three cylinders) is that it virtually drops straight in. All that was need was two new engine bearers, about 1 inch thick, which lined up the shaft with the output flange. The Yanmar is about 100 kg lighter, physically smaller and smoother running.

The new engine bearers are painted grey. The Bukh used to stand about a foot higher, which has enabled me to make a reasonably sized tool box that sits above the Yanmar.

 

[NickiCrutchfield]

Re: Replaced BUKH DV20 with Beta, BUKH..... or maybe even Nanni or Yan

I cannot comment on other makes as I have no knowledge or experience of them, but the Bukh, with certain limitations, is a fabulous engine. I rebuilt ours and the simple solidity of it won my heart. In 2001 I bought a gasket kit for about £800. I also bought a set of sockets and spanners and a torque wrench. My total expenditure, including servicing of the injectors, came to under £1100. I am no machanic so it was a voyage of discovery for me much, and I mean MUCH, helped by the fantastic advice offered by the Bukh men in Poole. I was on the phone to them at least once a day for A couple of weeks and any information the guy on the counter was unable to offer was instantly offered by Norman the mechanic. he generously gave me true inside mechanics knowledge with all experience of many years of working on these engines. They were even available for very good advice when we hit a small problem in the Canaries, fully aware of the difficulties of time involved in shipping parts. I even met them at SBS the following year and they had Norman on hand rather than some salesman.
Weight notwithstanding, and they are heavy, the engine which was 28 years old, is so stoutly built that the pistons and the bottom end were not touched. My compression was up to where it should be after a good scrape of the head, cast so no need for skimming, and re-grinding of the valves. As I said I am not a mechanic, but I thoroughly enjoyed the whole process. Every nut and bolt came undone without a serious problem. The longest single use we had of that engine was 193 hours with the only stops being for oil changes.
I'm sure such an engine is not for everyone, but the good things about it are so many that serious consideration should be given prior to simply removing it and replacing it with something which you cannot hand start. The cold starting issue can be easily got over my placing something hot (kettle full of hot water maybe, just below the air intake. Fuel consumption worked out at about 50 litres per 24 hours.
A fine, simple engine in my opinion.
I hope this is of use.
Nicki

 

[SpaceCygnet]

I have a Beta BD722 - in a boat when I bought 2 years ago. I have been very happy with it, plenty of power for our 30 foot, parts readily available and easy to service. As mentioned elsewhere, Beta offer excellent support.

 

[doug748]

I fitted the Beta 722 last winter and agree with much of what has been said. I would say that the 20hp unit is plenty for a 27' boat; with a larger unit might you end up running at minimal revs? I did not go for the special feet, finding it easier to fabricate flat plates which bolted on to the origianal beds. The new engine sat on these. I wrote up notes on the fitting for my class association, different boat of course, but if you think it may be of some use, PM me with your snail mail address and I will send you a copy. Brian.

 

[chrishelen]

Hi aiden,i replaced my Petter Mini six with a volvo 2001 that was rebuilt,My first engine installation,Looking back i should have just replaced it with another Petter because i needed to change everything,bearers,exhaust on the wrong side,nothing fitted,then to cap it all i discorvered that the prop shaft coupling on the Volvo is angled at 7 degrees,so i had to change the bearers again,a lot of naiivety on my part but i learnt a lot,might it be better and cheaper in the long run to rebuild your engine?it should last another 20 years then.

 

[PeterGibbs]

Some comments:

1. Not pushing in a seaway sounds like prop size / condition of hull issue. If the engine reaches full revs it's doing its job - your problem lies elsewhere.

2. Bukh's are heavy because there is a lot of metal in the galleries - that's why they last a long time. Others are lighter but being "more modern" is seldom a good reason for changing engine. As others have said, you may be lucky with a "drop in" replacement, more likely you will have lots of adjusting to do.

3. I take a simplistic view of engines - they are frames within which diesel is burned to produce rotary action. If the moving parts are replaced the frame is usually of no consequence.

4. The case for renovating your Bukh is dependent on how long you might keep the boat, as well as how far afield you're sailing. It is a relatively simple, even agricultural, design and very dependable / self maintainable (I've been there). It all hangs out, and is made of top grade materials. As you describe your needs, there is a real case for renovation - why not call Al or Norman at Bukh at Poole. I have know them for years, they know their engines back to front, and they will give you good advice without any pressure to buy. Tell them I will fry them if they fail my trust!

Peter Gibbs

 

[cindersailor]

One thing to note if taking the Beta route is that their 16 and 25 Hp engines are based on newer design Kubota engines than the 13.5 and 20 Hp ones. This was one factor which decided me on a 16 rather than the 13.5 for my 27 footer (3 tons). I find this to be more than adequate.

 

[aidancoughlan]

Many thanks for the responses folks.... plenty to think about.
I think if I could be guaranteed a good outcome with a rebuild I would lean that way... trouble is, it seems you dont know until you get into it what needs doing. Nanni is out based on resposes here & similar elsewhere - not many, but the same negative comments dont exist for Bukh or Beta. Yanmar I think may be too wide, which brings me back to my two first choices Bukh or Beta. I'll have a think over the weekend & discuss with my mates to see if I can rope them into an 'easy' Bukh replacement which would bring the cost down; I might call Al or Norman back to see if they might consider refurbishing the existing engine for me, or have it done under their supervision.(ps. If any body has any good first-hand comments about local diesel engineers in Dublin for a rebuild let me know.)


*****
BETA
*****
Fitting was pretty easy (or as easy as moving heavy lumps of metal into confined spaces can be !)

Don't underestimate the time and fiddle with all the engine connectiosn though (exhaust, diesel, water electric ets - chances are nothing quite fits !)

In the end I ditched the Bukh in my boat and went for a Beta DB722 that I got from Steve Birch.Much better engine in my opinion.Smaller ,modern and economical

In my opinion Bukhs are archaic designs

Secondly if I was going to spend a large sum on the engine doing up the old one would not do anything for the value of the boat, as you say its still an old engine wheras replacing it with a new one adds almost as much to the value as you spend on the engine

The piont you make about BUKH's not pushing the boat because they are low reving is wrong. Lower revs on a larger prop will give a more efficient drive with more power in the water

Beta very good in responding to problems/spares, Peachments (who are main Nanni people in UK) slow, don't respond, send wrong bits out etc. Wish I'd had the Beta instead

As mentioned elsewhere, Beta offer excellent support.

would say that the 20hp unit is plenty for a 27' boat; with a larger unit might you end up running at minimal revs?


One thing to note if taking the Beta route is that their 16 and 25 Hp engines are based on newer design Kubota engines than the 13.5 and 20 Hp ones

*****
BUKH
*****
the Bukh, with certain limitations, is a fabulous engine. I rebuilt ours and the simple solidity of it won my heart.

much, and I mean MUCH, helped by the fantastic advice offered by the Bukh men in Poole

might it be better and cheaper in the long run to rebuild your engine?it should last another 20 years then.


Not pushing in a seaway sounds like prop size / condition of hull issue. If the engine reaches full revs it's doing its job - your problem lies elsewhere.

The case for renovating your Bukh is dependent on how long you might keep the boat, as well as how far afield you're sailing. It is a relatively simple, even agricultural, design and very dependable / self maintainable (I've been there). It all hangs out, and is made of top grade materials.

********
YANMAR
********
I replaced a Bukh 20 with a Yanmar 27. A big advantage of this choice (apart from more power and three cylinders) is that it virtually drops straight in. All that was need was two new engine bearers, about 1 inch thick, which lined up the shaft with the output flange.

 

[chriscallender]

Hi

One thing to be aware of is that a 23 year old Bukh probably has the old gearbox (Hurth ZF-6 I think) and that puts the output shaft at a different height than the new Bukh (new one needs to go down as I recall so can't be handled by spacers under the feet).

Bukh do make some adapter for the new engine to allow it to fit in old installations, don't recall the exact price but somewhere between £100 and £200 I think.

I went through this decision making last year and replaced a Bukh DV20 with a Yanmar 3YM. No right/wrong answer to this question but some points that were relevant to me

- I did the work myself and comfortably saved probably at least 1k compared to a DV24 even though new shaft and repitched prop were needed

- I was able to use the old mount beds - the new Yanmar is nearly a drop in replacement in that the shaft height could be adjusted to the Bukh height (assuming you do have the ZF-6 gearbox). Beta would have been more work since the heights and mount positions are rather different.

- The Yanmar feet are closer together, the engine is overall slightly wider and much shorter. This might still necessitate some changes

- Since its shorter, I could find no way to do it without replacing the propshaft with one that was about 20cm longer so that I could have the engine far enough forward to clear the hull

- I did a lot of prop calculations, and repiteched the existing RH prop down by an inch (using 2.62:1 Yanmar gearbox). This seems about right since the shaft revs will be slightly higher

- About 100kg lighter

- Fresh water cooling was somehow more attractive to me (just a heat exchanger to scale up/flush).

- Other things I needed/wanted to replace
- Seacock, skin fitting and raw water hose increased to 3/4 inch from 1/2 inch. Raw water strainer also replaced with a bigger/better one
- Exhaust hose and water trap replaced (don't ask why ;-) ). This is expensive
- Fuel hose and return hose replaced (different diameter)
- New anti-syphon loop (hose diameters again)
- New morse control cables (since engine was moved forward, old ones too short)
- Some rewiring between the 1-2-Both switch and the engine
- One problem is that nearly everything is swapped to opposite side of the engine (alternator, exhaust, starter motor, water pump,...)
- I probably should have replaced the cutless bearing but thought "if its not broken don't fix it". I'm getting a slight rumble at max revs which I atribute to a slightly worn cutless bearing (fraction of mm of play in the prop). This was probably present before but more noticeable now with higher shaft revs. New cutless over next winter?

- Overall, about 7 days (hard) labour and about 3700 pounds cash. It was not rocket science and I gained a huge amount of knowledge/mechanical confidence. It was hard work though, and there were some serious fustrations (as well as good times) along the way


Chris

 

[vyv_cox]

My experience was not the same as yours. I had the job done as their offer was too good to refuse - effectively the labour was free and they gave me a part-exchange on the Bukh. The Bukh would have been about 23 years old now.

The job was done afloat, so prop, gland, propshaft were untouched. I replaced the prop, as planned, three months later. Morse cables were also unchanged. The old 1/2 inch water inlet was also unchanged, I finally upped it ot 3/4 after about 5 years. Exhaust hose and trap unchanged. A short length of fuel hose was replaced.

 

[ionian]

Hi Aidan,
I think I have the same Westerly as you ,with a 23yr old Bukh 20
which is behaving itself at the moment.
I have the same problem making way through the water as you describe
with speed down to 3/3.5kn in f4/5 with light chop.
I think the 2-blade prop is the culprit, so whichever route you take,if you
have same,I would consider 3-bladed or folding prop for more power.
Personaly I would go for new unless I could do the recon myself but good luck whichever course you take.

 

[chriscallender]

I guess it also depends partly on how many of the other bits and bobs are also 23 years old and in poor condition. In my case the exhaust hose was collapsed internally, the morse cables outer part broken away for about 5 inches due to corrosion from sitting in bilge water, the fuel hoses were non-BS seethrough perished plastic and plenty of other scary stuff so a fair chunk of the work was needed anyway.

But I agree, the idea of doing a like for like swap afloat also makes a lot of sense and I seriously considered doing the same, since the shaft/gland/prop/skin fitting was pretty well OK, and those were the areas where I could have saved some time/effort.

By the way, I did get a reasonable amount of money selling the Bukh which I didn't include in the figures. I'd still have been tempted by effectively free labour though ;-)!

Chris

 

[scottie]

with regard to a slow reving engine not giving enough push
as a general rule of thumb a slower turning prop with a large blade area is the best option but not the best for minimising drag so any propeller is a compromise
to be efficient a propeller has to turn at the correct revs and be the right size for both boat and engine.
It may be that the correct propeller for your engine may be too big to fit the apperture so either reducing the reduction ratio or increasing the engine revs could give a better propeller size for the boat

 

[neil_s]

Aidan - Your engineer doesn't sound very familiar with Bukh engines. They have wet liners, so you don't rebore them, you buy new cylinder liners, liner seals, pistons, rings, head gasket and sump gasket and fit them. It would be adviseable to replace the big end shells, too. These parts come to about 700 or 800 GBP. The cylinder head might need new valves and valve guides and the crankcase breather in the rocker box can get a bit rusty if there is lots of cream sludge about (due to blowing past the pistons). I don't know how much these parts are, though. My Bukh had the same symptoms as yours last year ( been slowly getting worse over about 5 years). I have done a cheap job on it - just replacing the piston rings and grinding the valves. Fingers crossed for next season!

Neil