Info re Volvo MD11c

[ANDY_W]

My Westerly 31 is fitted with a Volvo MD11c which is running well
at the moment.
However, since it is 34 years old, the possibility of having to
replace it, due to scarce and expensive parts, is quite high.
In that event, I would want to fit the smallest, lightest diesel engine
that I can get away with.
To that end, it would be helpful if anyone could supply or show
me where to find a graph of horse power per revs.
With that info I can see what the real world effect on the boat is
of different horse power before it goes bang and I then have
rely on theoretical values.
The reasons for looking at smaller replacement engines are:

1. Cheaper to buy
2. A vast saving in weight; the Volvo weighs 250 kilos+ and a modern
small diesel weighs 80/90 kilos.
3. A smaller engine will have to work harder whereas I have yet to
need more than half revs in normal use. Light running a diesel
engine leads to an early demise.

Any relevant info would be appreciated.

Thanks,

Andy

 

[zambant]

Just a couple of thoughts for you....

Second hand md11 's are available for £250 - £1000

If it aint broke dont fix it ????

Have you priced up a new engine including all accesories, prop, shaft and installation costs?

As to a torque curve - tried talking to Volvo Penta?

Regards

John

 

[sailorman]

My Westerly 31 is fitted with a Volvo MD11c which is running well
at the moment.
However, since it is 34 years old, the possibility of having to
replace it, due to scarce and expensive parts, is quite high.
In that event, I would want to fit the smallest, lightest diesel engine
that I can get away with.
To that end, it would be helpful if anyone could supply or show
me where to find a graph of horse power per revs.
With that info I can see what the real world effect on the boat is
of different horse power before it goes bang and I then have
rely on theoretical values.
The reasons for looking at smaller replacement engines are:

1. Cheaper to buy
2. A vast saving in weight; the Volvo weighs 250 kilos+ and a modern
small diesel weighs 80/90 kilos.
3. A smaller engine will have to work harder whereas I have yet to
need more than half revs in normal use. Light running a diesel
engine leads to an early demise.

Any relevant info would be appreciated.

Thanks,

Andy

Light running a diesel
engine leads to an early demise.

Its done well so far

look @ the Beta / Nanni range
from memory the MD11 is 23 hp so a 21hp would fit the bill.
as stated you will almost certainly need a new shaft & possibly an exhaust system . dont forget a siphon vent on the new engine

 

[Tranona]

No point in worrying about what the current engine does as it will be nothing like the new engine so there won't be any points of comparison other than the new (Nanni or Beta?) will be smaller, lighter, smoother and outlast you!

You will need to replace everything, including exhaust system, prop and probably controls. Almost certainly you will find all the stern gear also needs replacing after 35 years. Get a quote for the whole lot.

As suggested the 20hp models will be adequate and the 25 only a bit bigger physically and not a lot extra money. Choice will depend on how much serious motoring you want to do.

 

[ANDY_W]

Many thanks for the replies; they all add to the database for when the need arises.
For once in my life I'm trying to be prepared!

I have actually managed to find the graph I wanted via Webcrafts resource page so all
credit to him especially as googling it did not throw up any links!

Regards,

Andy

 

[Tranona]

Interesting to have, but any new engine will rev at least 1000rpm more, have a different gearbox ratio and a different prop. So you need to spec your new engine to match your boat, not to replicate what you have.

 

[ianc1200]

"will be smaller, lighter, smoother and outlast you!"

If you search my posts for 2008 you will see this is not so! In brief, 5.5 year old Nanni, 5cyl 62hp, (£8000 ish) had its front little end go, three large vertical scores in bore, uneconomic repair, replacement another 7.5k and all of August & September lost. Nanni expressed absolutely no interest at all in what went wrong apart from selling me a replacement engine.

My point is, new engines are not always perfect.

And don't buy Nanni, Beta aftersales & help much better.

 

[sailingharry]

Andy,

I am looking for the exact same information, and Google was no help -- except it found this posting! Can you provide more detail on what you mean by "Webcrafts resource page," perhaps even a direct link?

Thanks,

Harry
Analysis
'79 Sabre 34
Mill Creek, Annapolis

Many thanks for the replies; they all add to the database for when the need arises.
For once in my life I'm trying to be prepared!

I have actually managed to find the graph I wanted via Webcrafts resource page so all
credit to him especially as googling it did not throw up any links!

Regards,

Andy