Fitting heat exchanger cooled engine into narrowboat

[TheBiscuits]

10 minutes ago, Tony Brooks said:

Not confused, I never said anything about swapping parts, just removing parts but the OP will have to fit a dry exhaust on the 20HP.

 

As the way I described kept the manifold full of circulating coolant but without the heat exchanger core - so exactly like an indirect raw water cooled engine in  respect of the coolant against the hot parts of the manifold I don't see your point. I would see the point if it were an aluminium manifold and the suggestion was to run it dry. Yes a silencer will be needed but he probably has one plus the exhaust from his tank cooled dry exhaust engine.

 

Apologies Tony - I meant confused about which engine on which boat we were discussing, not the technical fix needed!

 

@Philip's ideal situation is that he can simply swap the raw water bits and the saildrive bits off the Beta 20 Seagoing with the keel/skintank cooling bits and the PRM 90 bits off the Beta 16 Greenline and switch the two engines and replace the bits.

 

I don't know if it's possible, but it would save him a fortune if he can.  I don't know the answer, do you?

 

 

Edited December 30, 2020 by TheBiscuits

[Tony Brooks]

1 minute ago, TheBiscuits said:

 

Apologies Tony - I meant confused about which engine on which boat we were discussing, not the technical fix needed!

 

@Philip's ideal situation is that he can simply swap the raw water bits and the saildrive bits off the Beta 20 Seagoing with the keel/skintank cooling bits and the PRM 90 bits off the Beta 16 Greenline and switch the two engines and replace the bits.

 

I don't know if it's possible, but it would save him a fortune if he can.  I don't know the answer, do you?

 

 

I think in the main there is a good chance it will be but there is something coolant related on the back of the red manifold that may need modifying of the green manifold won't fit.

[J R ALSOP]

1 hour ago, TheBiscuits said:

 

Can you state your objections more clearly?  Do you (wrongly!) think it isn't BSS compliant, or do you just not like the appearance of plywood and think it needs painting?

 

 

I would have thought that it should be fitted with a metal or FRP lining.

[Alan de Enfield]

16 minutes ago, J R ALSOP said:

I would have thought that it should be fitted with a metal or FRP lining.

 

That is a BSS requirement to section 7:2:1

 

"wooden cylinder lockers must incorporate a lining of FRP, or equivalent to meet this requirement".

[Philip]

I think from what I've read here and giving some thought it might be worth just sticking with the 16hp, but perhaps welding in the second skin tank to provide extra cooling if needing to use high revs for a while. Even without buying a new engine it'd quite a job swapping the engines around and having to adapt each to the different transmission and cooling arrangements. Only 105 hours on this Beta 16, compared to the 1500 on the 20hp in my cruiser.

 

Anyone know roughly how big the fuel saving is between the 16 and 20hp engines, assuming both are geared and propped correctly?

[Alan de Enfield]

7 minutes ago, Philip said:

Anyone know roughly how big the fuel saving is between the 16 and 20hp engines, assuming both are geared and propped correctly?

Roughly "none"

 

A diesel engine only uses enough fuel to produce the power needed - it will take ~5-7hp to move a NB so it doesn't matter if you keep the 16hp or install the 20hp. Both / either will only be producing 5-7hp.

 

 

Both engine will use ~1.5 litres per hour

 

Diesel engines use approximately 1 gal  (4.4 litres) per hour per 20 HP developed :

Fuel consumed is proportional to the power developed

Power developed is approximately proportional to the cube of the engine revs

Hence fuel consumed is proportional to the cube of the engine revs.

 

Consumption = C x RPM3

Where C = Max Fuel Consumption at WOT / RPM3

(Take revs as ‘single figures’ ie 2000 rpm as 2.0, & 2600 rpm as 2.6)

 

Edited January 2, 2021 by Alan de Enfield

[OldGoat]

1 hour ago, Philip said:

I think from what I've read here and giving some thought it might be worth just sticking with the 16hp, but perhaps welding in the second skin tank to provide extra cooling if needing to use high revs for a while. Even without buying a new engine it'd quite a job swapping the engines around and having to adapt each to the different transmission and cooling arrangements. Only 105 hours on this Beta 16, compared to the 1500 on the 20hp in my cruiser.

 

Anyone know roughly how big the fuel saving is between the 16 and 20hp engines, assuming both are geared and propped correctly?

"Yea" - just open the throttle a little bit wider.....