Beta/Nanni 10hp convert to 14hp?

[capetown]

Thinking about a new engine and wondering if it's more economic to buy the 10hp and convert it to larger hp.

Has anyone done this?

What, if any parts need to be changed/added.

Is the exercise worthwhile?

Comparing specs it seems the 14 has a sump pump and the revs are 3600.

Always looking to save a few bob.

Thanks.

 

[sailorman]

Thinking about a new engine and wondering if it's more economic to buy the 10hp and convert it to larger hp.

Has anyone done this?

What, if any parts need to be changed/added.

Is the exercise worthwhile?

Comparing specs it seems the 14 has a sump pump and the revs are 3600.

Always looking to save a few bob.

Thanks.

what rpm for the 10 hp

 

[LittleSister]

The Beta 14 and 10 are basically the same engine. The 10 is limited to 3,000 rpm. The 14 (actually 13.3hp) also gives c10hp at 3,000 revs, but revs up to 3,600 to give its full power.

IIRC the 14 is only about £300 more than the 10 (at least at boat show prices), and includes some bits like the sump pump you mention (an optional extra on the 10hp). Might not be worth the bother, perhaps, unless its just a matter of an adjustment, rather than repalcing parts.

 

[sailorman]

The Beta 14 and 10 are basically the same engine. The 10 is limited to 3,000 rpm. The 14 (actually 13.3hp) also gives c10hp at 3,000 revs, but revs up to 3,600 to give its full power.

IIRC the 14 is only about £300 more than the 10 (at least at boat show prices), and includes some bits like the sump pump you mention (an optional extra on the 10hp). Might not be worth the bother, perhaps, unless its just a matter of an adjustment, rather than replacing parts.

imho 3600 is too fast for a displacement boat.

 

[TQA]

imho 3600 is too fast for a displacement boat.

Gotta gearbox??

3600 rpm not that unusual.

 

[sailorman]

Gotta gearbox??

3600 rpm not that unusual.

but not necessarily good 3k is much better

 

[capetown]

The 10hp is stated at 3000 rpm.

I'm wondering how the revs are limited?

I'm not too fussed about the pump.

 

[prv]

but not necessarily good 3k is much better

What difference does it make?

The venerable Yanmar 2GM20 found in thousands of boats is rated to 3600 as well.

Pete

 

[sailorman]

What difference does it make?

The venerable Yanmar 2GM20 found in thousands of boats is rated to 3600 as well.

Pete

thats how they get the hp by high rpm, i prefer a less stressed engine in my boat

 

[parbuckle]

I think the RPM is increased by more fuel metered by a sliding centrifugal device on the end of the camshaft via the rack connected to the fuel pump.I think the lower revving engines are more likely to be used for generators and compressors as they require steady revs for long periods.
To convert to more RPM could require a different camshaft and adjustment to the fuel pump , if so is not a goer.

 

[LittleSister]

imho 3600 is too fast for a displacement boat.

Works fine in our heavyweight long-keeler.

thats how they get the hp by high rpm, i prefer a less stressed engine in my boat

Our Beta engine doesn't seem stressed at those revs, though we rarely need to use that much power (and neither does my car or motorbike engines, neither of which are racy, and both rev to over twice that). The Kubota base engine is built as a stationary engine, designed to be able to run continually at such speeds.

 

[wolf]

Void your warranty

Altering the revs will void the warranty may cost you more than you save.

 

[Tranona]

imho 3600 is too fast for a displacement boat.

'fraid that is just rubbish. The boat does not care what revs the engine runs at. It is the speed of the shaft and the prop that does the job of propelling the boat. The Nanni (and most other modern diesels) is available with a large reduction gearbox to bring the shaft speed down to drive large diameter props if required.

Just about all the small diesel engines are designed to run above 3000 rpm but are unstressed as they have low specific outputs of less than 30hp/litre. They will just about never wear out in normal use in a yacht auxiliary as they have a design life of 8000 hours+ - over 50 years of typical usage in a yacht.

 

[Tranona]

Thinking about a new engine and wondering if it's more economic to buy the 10hp and convert it to larger hp.

Has anyone done this?

What, if any parts need to be changed/added.

Is the exercise worthwhile?

Comparing specs it seems the 14 has a sump pump and the revs are 3600.

Always looking to save a few bob.

Thanks.

If your boat only needs 10hp then buy that engine. If it is able to use 14 then buy the higher output version for very little more money and get the benefit of the extras such as the higher output alternator - as well as the 30% increase in power.

 

[sailorman]

'fraid that is just rubbish. The boat does not care what revs the engine runs at. It is the speed of the shaft and the prop that does the job of propelling the boat. The Nanni (and most other modern diesels) is available with a large reduction gearbox to bring the shaft speed down to drive large diameter props if required.

Just about all the small diesel engines are designed to run above 3000 rpm but are unstressed as they have low specific outputs of less than 30hp/litre. They will just about never wear out in normal use in a yacht auxiliary as they have a design life of 8000 hours+ - over 50 years of typical usage in a yacht.

you are welcome to your opinion.
my engine is rated @ 3000 RPM that was my choice

 

[rotrax]

imho 3600 is too fast for a displacement boat.

Perhaps you should tell Yanmar then. Our boat has an older generation 38hp three cylinder that provides its maximum output at exactly 3,600RPM. There is no way our heavy long keeler could be described as anything other than a displacement hull. I know all about the virtues of slow reving torquey marine diesels but most require far more space for insallation than modernish-built within the last 20 years- engines and are often noisey and require more frequent attention to some of their systems. The diesels in the last three boats I have owned have been a revelation compared to the older generation ones I have experience of. The fuel efficiency is superior too.

 

[sailorman]

Perhaps you should tell Yanmar then. Our boat has an older generation 38hp three cylinder that provides its maximum output at exactly 3,600RPM. There is no way our heavy long keeler could be described as anything other than a displacement hull. I know all about the virtues of slow reving torquey marine diesels but most require far more space for insallation than modernish-built within the last 20 years- engines and are often noisey and require more frequent attention to some of their systems. The diesels in the last three boats I have owned have been a revelation compared to the older generation ones I have experience of. The fuel efficiency is superior too.

i took out a 4108 & replaced it with a 4 cylinder Nanni, both rated @ 3000 RPM

 

[capetown]

Thanks

Thanks all,

It's just the info I need to decide to get the 14hp.

What a good forum.

 

[rotrax]

i took out a 4108 & replaced it with a 4 cylinder Nanni, both rated @ 3000 RPM

It would appear to me that your preference is because that is what you have. There is no reason these days for a marine diesel to be slow reving. The Perkins was a good reliable donk but a bit old fashioned by todays standards. The Nanni is another good reliable engine. The fact that it is rated at 3000 rpm may just be a function of the fueling. I expect it would be capable of more rpm if set differently. When we are cruising under engine in our boat the "sweet spot"- most engines have one- is at 2600 to 2750 rpm. This is what we use. The boat progresses OK, it is fairly quiet and much more fuel efficient than at 3600 rpm. We have used full rpm for several hours in adverse conditions to reach a safe haven. It gives another knot and a half of speed, a bit more noise and a little bit of black around the exhaust outlet. Our engine has over 3000 hours on it, and I expect many more.

 

[Latestarter1]

'fraid that is just rubbish. The boat does not care what revs the engine runs at. It is the speed of the shaft and the prop that does the job of propelling the boat. The Nanni (and most other modern diesels) is available with a large reduction gearbox to bring the shaft speed down to drive large diameter props if required.

Just about all the small diesel engines are designed to run above 3000 rpm but are unstressed as they have low specific outputs of less than 30hp/litre. They will just about never wear out in normal use in a yacht auxiliary as they have a design life of 8000 hours+ - over 50 years of typical usage in a yacht.

Have to violently agree with Tranona. When I hear people saying this and that is too stressed it is all un-databased backside talk.

In reality an engine of the same swept volume developing 10 hp @ 3,000 rpm may have marginally higher BMEP than the 14 hp @ 3,600 rpm rating. These little puddle jumpers never break into a sweat as max BMEP is never much more than 700 kPa which is why they have potential to out live any owner over 60.

Plus the fact motors if correctly specced rarely asked to run at rated speed anyway.