Date:         Thu, 20 Jun 1996 14:34:38 -0500
Sender:       Vanagon Mailing List <vanagon@vanagon.com>
From:         bighouse@socomm.net (Ken Hooper)
Subject:      Re: Oil cooler for 81 (and 67) Westy


>Actual location (available space) of the 72-pass Mesa cooler with the
>electric fan is my problem.

>Another suggestion boils down to some sort of
>cutting of the metal in the driver's side battery tray coupled with some
>sheet metal fabbing to create an exit port/dump for the hot air coming off
>of the cooler.

Just thinking out loud, by a non-guru:

You've got two different problems.

  (a) Where the cool air comes from

  (b) Where the hot air goes

There's also the issue of where the cooler itself sits. Let's look at that
first:

If the cooler won't fit in the engine compartment, then it won't fit in the
engine compartment and that's that. If it were me, though, I'd fab another
smaller or differently-shaped cooler, so I could fit it in there, for the
following reasons:

(a) Where the cool air comes from:

Obviously you want the coolest air possible, and obviously you want to
avoid the exhaust, but you also want the air from as far away from the road
as possible. On a 120 degree day in Phoenix, how hot does the blacktop get?
150? 200? I don't think you want to be pulling air from under the bus, 6
inches from a surface that radiates like a barbeque grill. You want the air
to come through the louvers.

Surely the top of the engine heats the air in the engine compartment a
little, but it's the coolest air you can get to start with and it moves
through there at high volume as it's pumped out through the engine's
cooling system. So short of rigging up a snorkel to the roof, it's probably
the coolest air you can get. You want to get the cool air from inside the
engine compartment.

(b) Where the hot air goes:

You don't want the oil cooler to exhaust inside the engine compartment
because that would raise the temp of the air blowing over the cylinders and
heads (negating the whole excercise?). You want it to exit the bus and not
come back in through the louvers.

I understand why you don't want to cut up the body of the Resto from Hell,
but how about this:

(Short detour--four wheel drive zealots spend a lot of time lugging their
engines, doing low-speed high-torque manuevers, and that's the sort of
thing that makes watercooled engine temps skyrocket. They spend a lot of
time trying not to overheat, too, just like us. Their first rule is
*shroud*. It's the cheapest and single most effective thing you can do with
a radiator.

Shroud the entire surface of the radiator into a cut cone with the
circumference of the small end being barely larger than the fan, so the fan
can't draw air that hasn't been through the radiator. But they dump their
air in the engine compartment, and we can't do that, so let's go even
further and shroud the exhaust.)

Mount the fan in a sheet-metal cone, with the smaller end of the cone
terminating in a big flexible pipe. Like one of those pipes they use with
the gas heaters. Then cut a hole <grimace>, but cut it in the apron and run
the pipe to it. Come on, aprons are a dime a dozen, you can easily return
it to stock. This way it dumps the hot air right onto the engine exhaust,
which is where it ought to go.

It sounds like this would all take a lot of room, but it shouldn't because
it doesn't matter how obtuse the angle of the cone is. You can make it
extremely shallow and it makes no difference as far as airflow goes.

Does any of that make sense? Is this all stuff that's already been thought of?

--Ken