Does a diesel need extra air intake to space?

[Flyboy]

Just a thought,but if this amount of fresh air is needed to keep the engine running at optimum tempature, would it not be easier to drill a small ish hole in the deck and just attach a snorkel direct to the air intake, as seen on 4x4,s ??

You still need to keep the engine room temperature down, your proposal would make it worse. By allowing the engine to draw air in will help to achieve a cooler environment.

[Polishicebreaker]

Just a thought,but if this amount of fresh air is needed to keep the engine running at optimum tempature, would it not be easier to drill a small ish hole in the deck and just attach a snorkel direct to the air intake, as seen on 4x4,s ??

Damn, that's exactly what my neighbour has been saying for about a year and I partly started this thread to prove he may be talking bollocks

[aread2]

Beta BV1903S

Beta Marine's super silent acoustic box is quite well sealed from the outside. On the left of the picture (in front of the engine) they have provided some large vents. These are positioned opposite the alternators; not by accident. Also on the right there is a blower to remove warm air, roughly doubling the intake of fresh air to the housing.I think you'd have a hard time sealing an engine room on a narrowboat sufficiently to cause problems with combustion intake. The main danger would be the reduction of cooling air flow over the alternators.

[steamraiser2]

Question is, does my water cooled engine and others need a air intake to the compartment?

i.e blowers etc and some kind of outlet.

I see some boat owners are in favour of this but interested in others opinions.

This is for a 52 hp engine in a space of approx 4 cubic M with tight fitting deckboards and no vents

 

Cheers Ed

 

 

I don't think the Op was asking about the volume of air into the engine but the flow of air through the engine bay / room? In simplest terms you need a decent size air inlet and a big enough air outlet to dissipate heat. The manufacturers installation instructions usually indicate the sizes recommended for this. If opening the engine room door releases a blast of heat like the boiler room of the Tirpitz 'taint big enough vents for sure !

[system 4-50]

Isn't the exhaust the air outlet? You only need vents for air inwards? Or is the engine intelligent enough to know that one vent is supposed to be the inlet and the other the outlet?

And while I'm at it, I still think the inside side of the keel cooling tanks should be insulated, provided they are of a decent size and not need to lose heat inwards.

[MtB]

Question is, does my water cooled engine and others need a air intake to the compartment?

i.e blowers etc and some kind of outlet.

I see some boat owners are in favour of this but interested in others opinions.

This is for a 52 hp engine in a space of approx 4 cubic M with tight fitting deckboards and no vents

 

Cheers Ed

 

Feckin' ell!! This is for a 80ft x 10ft Dutchman, right?

 

 

MtB

[Polishicebreaker]

 

Feckin' ell!! This is for a 80ft x 10ft Dutchman, right?

 

 

MtB

only haif that am afraid. 40 ft long

[blackrose]

I thought about putting a bilge blower next to one of my engine room vents, switched from the boats control pedestal, to draw more cold air into the engine space. I just thought that the engine would be more efficient if it was using cooler air. Haven't got around to it yet but after reading this thread I'm not sure if it would work anyway.

[RLWP]

I thought about putting a bilge blower next to one of my engine room vents, switched from the boats control pedestal, to draw more cold air into the engine space. I just thought that the engine would be more efficient if it was using cooler air. Haven't got around to it yet but after reading this thread I'm not sure if it would work anyway.

 

It would probably work, but it's likely to make such a small difference you won't notice

 

Unless the power to run the blower was significant of course, in which case it would reduce the efficiency

 

Richard

[OldGoat]

I fitted four large server room computer fans in my engine bay - worried about tales of 'insufficient cooling air' in restricted spaces.

Two are switched on when the engine runs and two manually switched when we get a hot summer.

 

I've absolutely no idea whether they do any good...

 

 

 

 

 

 

 

 

 

 

 

 

 

 

.but they keep me happy - what's not to like

[Phil Ambrose]

I have a computer fan mounted on my alternator to cool it down a bit. Not sure if it works but as Old Goat says, "it makes mr happy"

Phil

[Dalslandia]

Saw something that the air inlet to the engine room should be one third of the HP in size, in sq.-inch and even better 10% larger then that.

 

and from memory the Nordic small work boat rules, said 7 cm2 per kW or about 5,15 cm2 per HP

 

50 hp then need 16,7 sq in, or 4.1"x4.1" INLET

or 107,5 cm2 that's only 2,15 cm2 per HP

For inlet that is, it also need a outlet that is 30% bigger.

 

so then total we need for 50 HP 107,5+139,75 = 247 cm2 / 50hp = 4,945 cm2 per hp

so basically the same as the Nordic small work boat rules.

Edited March 27, 2015 by Dalslandia

[Bee]

I have always tried to get as much air around the engine as possible, it just seems good practice to ventilate it to disperse inevitable fumes from odd leaks and filter changes and so on.

[blackrose]

 

It would probably work, but it's likely to make such a small difference you won't notice

 

Unless the power to run the blower was significant of course, in which case it would reduce the efficiency

 

Richard

I think it's only a couple of amps at 12v.

[blackrose]

Thinking about it, connecting the air intake to a fitting in the deck or hull side has the added advantage of being easy to smother in the event of a runaway engine, and means you don't need to lift deckboards (on a cruiser stern) or get anywhere near the engine itself.

 

I guess the only disadvantage is that whatever sort of deck or hull fitting is used, it's possible to accidentally get water in the pipe when cleaning the boat or on a tidal journey. Quite a significant disadvantage really if it gets into the air intake!

Edited March 27, 2015 by blackrose

[Naughty Cal]

I thought about putting a bilge blower next to one of my engine room vents, switched from the boats control pedestal, to draw more cold air into the engine space. I just thought that the engine would be more efficient if it was using cooler air. Haven't got around to it yet but after reading this thread I'm not sure if it would work anyway.

We have bilge blowers on our boat.

 

Occasionally if it is very hot we will switch them on if doing a long high speed run. Whether they help the engine breathe or not I don't know, but there really isn't a noticable difference with them on or off.

[blackrose]

Yes, on one hand if the difference in performance isn't perceptible then perhaps they aren't worth having, but on the other hand could there be other things like better fuel consumption or less wear and tear on external engine parts like fanbelts that makes cooling the air around the engine worthwhile?

[craftycarper]

Me personaly would just rely on the tempature gauge on the engine, as long as you have one, if you are running all day and the temp stays the same leave alone, if on the other hand you get a bit warm on long journeys or river trips fit some extra cooling, I have a grill muff ( I know but that's its name) on my old landrover, in the winter I keep it closed, otherwise it runs to cold and I get know heat from the heaters in the summer it opens and allows cold air over the engine,simple and effective just how I like it

[Neil2]

Thinking about it, connecting the air intake to a fitting in the deck or hull side has the added advantage of being easy to smother in the event of a runaway engine, and means you don't need to lift deckboards (on a cruiser stern) or get anywhere near the engine itself.

 

I guess the only disadvantage is that whatever sort of deck or hull fitting is used, it's possible to accidentally get water in the pipe when cleaning the boat or on a tidal journey. Quite a significant disadvantage really if it gets into the air intake!

 

I thought about a sort of snorkel for the air intake but dismissed it for that very reason, I couldn't think how you could eliminate the possibility of water getting in the tubing. Also you would be exposed to induction "roar" - I don't know how significant that is on a diesel.

 

But you could have a fat tube connected to a mushroom or ufo vent direct to the engine room which is what I'm planning to do.

 

The CE regs do require engine room vents on a narrowboat so if you have a "modern" boat it should have them anyway. That's nothing to do with the engine it's a fire safety thing.