Maybe I misunderstand but are you asking about the little round ones close
to the sole?
I don't know where to find them but if that is all the venting for that
engine box, your engine will not get enough air.
It would not be sufficient for a gas engine but diesels need twice the air
of a gas engine.
There should be large louver vents on the front or side of the engine cover.
If that is not possible esthetically, you may want a blower that sends air
in the bilges.

PS: engine installations where my primary business for 10 years.


--
Jacques
http://www.bateau.com



"Gary Warner" wrote in message
...

I've asked a few times if anyone knows where to get vents like
these, but this time I actually have a link to pictures - so that
may help.

These are pictures of an engine cover on a boat similar to ours.

http://www.shutterfly.com/osi.jsp?i=...21b321e102454c

Thanks!
Gary

"Jacques Mertens" wrote in message
...
It would not be sufficient for a gas engine but diesels need twice the air
of a gas engine.
If the two engines are of equal capacity and turning at the same speed and
both are say four stroke engines then why would diesel require twice the
amount of air?

Compression ratio.

"L & D milligan" wrote in message
...

"Jacques Mertens" wrote in message
...
It would not be sufficient for a gas engine but diesels need twice the
air
of a gas engine.
If the two engines are of equal capacity and turning at the same speed and
both are say four stroke engines then why would diesel require twice the
amount of air?

"Jacques Mertens" wrote in message
news
Compression ratio.


Makes sense. But wouldn't the higher compression ratio of diesels be at
least partially offset, if not completely, by their significantly lower
operating RPM's when compared to gas engines? Seems between these two
offsetting factors, air consumption should be pretty close to the same given
similar displacement and operating duties. Just thinking out load.

It has nothing to do with compression ratio actually. The amount of air is
increased because a diesel has no throttle blade nor is any measurable
amount of manifold vacuum created. A diesel of say 400 cubic inches uses
the same air a gas engine of 400 cubic inches would if it were run wide open
100% of the time.

--
Steve
=======================
Remove the not dot from my address to abuse my email box
"L & D milligan" wrote in message
...

"Jacques Mertens" wrote in message
...
It would not be sufficient for a gas engine but diesels need twice the
air
of a gas engine.
If the two engines are of equal capacity and turning at the same speed and
both are say four stroke engines then why would diesel require twice the
amount of air?

But you would need to size vents for full throttle anyway ....
I think we are all guessing so far ....

I'd have thought a "gas" ( petrol in this part of the world ) engine might
have been less forgiving of pressure drop through the vents. Or it might be
something to do with cooling?
David


"Steve Barker" wrote in message
...
It has nothing to do with compression ratio actually. The amount of air
is
increased because a diesel has no throttle blade nor is any measurable
amount of manifold vacuum created. A diesel of say 400 cubic inches uses
the same air a gas engine of 400 cubic inches would if it were run wide
open
100% of the time.

--
Steve
=======================
Remove the not dot from my address to abuse my email box
"L & D milligan" wrote in message
...

"Jacques Mertens" wrote in message
...
It would not be sufficient for a gas engine but diesels need twice the
air
of a gas engine.
If the two engines are of equal capacity and turning at the same speed
and
both are say four stroke engines then why would diesel require twice the
amount of air?

Jeez, the guy seems to have forgotten that air supply requirements for any
engine is a factor of rpm vs displacement. Size to WOT, of course, for
gasoline or diesel. However, typically diesel WOT rpm will be much lower than
gasoline(petrol) WOT rpm.

Right?

Butch

David said: But you would need to size vents for full throttle anyway ....
I think we are all guessing so far ....

I'd have thought a "gas" ( petrol in this part of the world ) engine might
have been less forgiving of pressure drop through the vents. Or it might be
something to do with cooling?
David


"Steve Barker" wrote in message
...
It has nothing to do with compression ratio actually. The amount of air
is
increased because a diesel has no throttle blade nor is any measurable
amount of manifold vacuum created. A diesel of say 400 cubic inches uses
the same air a gas engine of 400 cubic inches would if it were run wide
open
100% of the time.