Replace a Bukh with a Bukh, or something else?

[neil_s]

Keep the DV20!

Some useful tips -

Early DV20's were fitted with the ZF BW6 gearbox. Later ones had the BW7, as does the DV24. The output shaft drive line is a little higher on the BW7 gearbox, so if you replace an early engine with a later one, you will need to reduce the height of the bearers. I don't know the age of your engine, but mine is 1977 and it has the BW6 gearbox.

The DV24 has direct injection and thus may be a little noisier than the DV20. I am told they are also easier to start.

Your oil leak problem might be due to excessive crankcase pressure - not oil pressure. The breather valve under the rocker box can get blocked up and might need a swill out in petrol.

The Bukh engines are rated continuously - they can maintain 20 HP output 24/7. The Beta engines and other Kubota adaptions are not. To get an equivalent engine you would need to go for a higher nominal power output. This fact persuaded me to stick with my Bukh!

Cheers! Neil

 

[Babylon]

Thanks to all

Thanks people for all the feedback! I've learnt a huge amount about my engine and the various options in an incredibly short space of time, and feel much more informed when dealing with the engineers.

I don't, due to pressure of work and family stuff in the short term have the time (or expertise yet), to do more than instruct the boatyard and engineer to do the work, but - as I say - I'll be more confident when discussing the on-bench diagnosis and options/costs with the engineer in due course.

Cheers

Babylon

 

[snooks]

Just one thought - have you had the oil breather pipe removed and cleaned? They are an absolute pain to remove - needs masses or torque on the wrench but Bukh say a clogged breather is the biggest cause of oil leaks as the pressure gets way too high. It's a job you can do in situ though. Best of luck with the decision.

The oil breather filter can be removed by a little screw under the filter, that holds it onto the angled plate without disturbing any of the nuts holding the cylinder head down, so you don't need a torque wrench.

If you can find a friendly mechanic with a penchant for beer, it's possible to borrow a torque wrench if you have that desire to make more work for yourself

 

[snooks]

Thanks people for all the feedback!

If you do decide to replace, depending on the condition of the engine, you can get quite a few hundred pounds by selling it on Ebay. Lots of bukh owners out there need spares

 

[PeterGibbs]

I don't think this is an engineering decision.
To consider changing a good running engine you must be planning to keep the boat 10years +.
If you feel you might feel the need to change the boat in 5 years, or less, then I would consider doing nothing. You like it, it's mended and it could go for the next ten years without attention. If it does let you down badly in the near future, consider a rebuild.
Should you be in it for the long term then an engine upgrade could be worth it (in the next 5 years/when it next breaks down). I could not find a quick price for the Bukh but I would guess £6,000, a useful Beta would be a touch under £4,000 plus all the fussing to put in engine plates. The exhaust is on the wrong side and so are the controls but that is not a huge probelm, given that you may upgrade these anyway. They both spin the same way so you could probably re-cycle your stern gear if it is good. The Bukh is raw water cooled, so at least you could get easy hot water if you fit the Beta (or similar).
So more trouble to fit the Jap engine against probably more cost for the Bukh.
Faced with a similar choice I simply picked the one that everyone else was fitting to my class of boat. Easy.

Much wisdom here. Your account does not indicate the Bukh is shot - it's not that easy to define when one actually reaches that stage. A new head gaskit (I've done that - as a non-engineer) and it's off to the races for seasons to come. Any reason to suspect the main bearings? Either the unit delivers reliable power or it doesn't.

Bukh's are agricultural - the galleries are laid up much heavier than most engines, so corrosion there (probabaly a fatal condition in any angine) is not likely to beset the unit for many years, given even medium care. The exhaust elbow is vulnerable and not cheap to replace when it goes, but that's visible and relatively easy to fix. The water pump is ready to hand and easy to maintain. Sometimes the sump rots out - not a problem here apparently. But if the main fuel pump creaks or goes, then there is a serious case for looking at something new - hardly anything else here can be that decisive for you.

A new engine? If you're going to keep it for a number of seasons, ok. But if not, you know what to do.

Good luck,

PWG

 

[30boat]

If your engine is working reliably,I don't see the need to replace.My earlier reply was based on the assumption it wasn't.One thing to watch is the chain to the raised hand start.I had one break that took the casing with it.After many years these engines tend to get corrosion on the seal bearing surfaces on the crankshaft.When that happens it is almost impossible to cure the resultant leaks.It doesn't make the engine unreliable only messy.

 

[Twister_Ken]

While you've got it out, strip off the ancillaries, clean up what's left and repaint it in Bukh red. It'll look like a new engine and impress a surveyor.