I just checked all my saved e-mails on A/C cores - and I find NONE where
someone reported he had cut one open and thoroughly examined the flow path
and details related thereto.  This recent info indicates to me that the
plates "2 inches down from one pipe" must be to cause "serpentine flow",
i.e., block off maybe bottom 2/3 so liquid flows across one way only in

top third, then another blocking plate 2/3 down on the other side forces

liquid to reverse course and go back across in the opposite direction,
coming out UNDER the first blocking plate on that side, the being forced
down to reverse course through the bottom third.  Then, when it comes out

bottom third of tubes on far side (from original inlet), it has to get

to the top "exit tube" on the far side - that must be what the "inside

is for - to go thru the blocking plate on that far side.  Does this make
sense?

Now, having said that, I just found and reviewed a note I made last 17 Nov
03.  I called the guy at www.frigidair.net and asked specifically about
"serpenine" or not? on the Caprice evap cores he makes and sells from the
web site.  The website doc even has a column, which is blank, labeled
"Serpentine".  That is what prompted my call to him, to confirm if there

or is not, serpentine flow.  He said they were just like a radiator - all
the stuff goes in on one side and flows across all the tubes in one
direction to the other side and out.
    -  Now, he is an "aftermarket"mfr of "OEM" cores.  Thus, the cores
"should" be same as OEM, the stuff we are taking out of cars.
    -  Base on this latest report that there is a "blocking plate", I no
longer believe the guy's info.  Either he doesn't know how his stuff is

or he is not making it the way GM/Harrison made them.

So, please tell us again, and more, about "removing the tube":  Wasn't it
welded to a "blocking plate" (so no leaks around it)?  Or was it a fairly
close or tight fit thru a hole in the "blocking plate" to make leaks
inconsequential?

In any case, based on what I think has been reported and what I understand
about a 3 layer "over, back, and over again to the other side" serpentine
internal construction, here's why I believe you are cooling only on the

third of the core:
    -  The coolant comes in on the side with blocking plate 1/3 of way

and there was never any tube in that side - stuff can't get past that

and is forced "over" thru top 1/3 of tubes.
    -  Once it gets to the other side, with the tube removed, there is a
hole directly "out" the top of the core, which is where the fluid goes.

the same time, if any tries to go down and "back across" to original side,
it really won't flow, as it is also going down through the hole left in

"2/3 down blocking plate" when the tube was removed from hole in that

and so fluid tries to flow "back through both the "middle third" and, if
goes down thru hole in blocking plate, also tries to go "back" thru bottom
third, so going across both middle and bottom thirds - and nowhere to go -
just a stagnant flow area with no outlet.
    -  So, all the flow from top 1/3 goes out the top and "warm stuff"

sits in the bottom 2/3 of tubes.

Sound like what you are seeing/feeling?  If so, putting the "tube on
2nd/exit side" back thru the "2/3 down blocking plate" should restore

serpentine flow, with all fluid come OUT of the TUBE you just put back in,
which has to either be sticking out of top of that "end cap" or be welded

the top, so nothing from top 1/3 can escape without going thru the entire

pass serpentine path".

David

----- Original Message ----- From: "Russell Duffy" <13brv3@bellsouth.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Monday, September 06, 2004 8:35 PM
Subject: [FlyRotary] Re: Water pump problem


No.  It had one tube in each of the tanks.  Both in the top.   One tank is
blocked off by a plate about 2" down from the top.  The other tank
originally had a tube in it internally that extended to within an inch or

of the bottom.

Does that make sense ?


I must be misunderstanding something, because I don't see how the original
configuration could have been using the whole core in the car.  Let's

that for now though.

You should now have a tube in each tank.  Both tanks should be open from

to bottom, meaning that you'd have to have drilled a hole through the
blocking plate that was installed in the tank.  If you didn't open up the
blocking plate, you're only using the top two inches of the core, which
would explain why that's all that's getting hot.

To rephrase this another way, one tube should come into the top of one

The liquid running into the tank should be able to go through every one of
the flat tubes that join the tank.  The liquid should be able to come out
every one of those flat tubes in the other tank, and go up and out through
the outlet tube.  Is that what you have now?

If the above wasn't clear, I'm afraid we're going to have to resort to
drawings :-)

Cheers,
Rusty (glad the South FL boys survived)





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