<< Ken Powell wrote:

Lynn,
Are you advocating the use of a GM air conditioning evaporator?  Have
you used one or know of someone who did?  I have wondered about this
subject.  They should handle the pressure OK; is there a pressure
spike on a cold startup that could be a potential problem?  I had
thought that the oil viscosity was too high to flow properly.  Any
details would be appreciated.

Ken Powell

Yes. That's all I had back in the 70s. No money at all.
I would check the automotive air conditioning shops for free cores. If the leak is not in the part I needed, wow, a free oil cooler. After the leak check, make up a fitting, or convince your wife to hold an air chuck in one end to pressurize it while you hack saw off the tubing welded to the other end, and vice-versa. This is messy. There is oil in there. The 1/8" tube on the bottom just pinch off with diagonal cutting pliers. 

Line two pieces of 3/4" plywood with a thin foam sheet and clamp the core between the
sheets. Clamp two 2x2s to the drill press bed. Clamp the core and the plywood sheets
to the 2x2s. With the wife in a rain suit,holding the air chuck in the other end,
drill out the welded tube with a 3/4" hole saw without the pilot drill installed. Use
a little WD40 and very slowly drill out the weldment. This is hard to do, so you
might want to practice on some soft scrap stock before you start with the wife
watching. This is real nasty, with oil and metal chips flying!

. Wear eye protection. 

When done clean it out as though it were full of metal chips. Cut up two dash 12 AN
fittings and sand off the anodize from the faces of the hex flats. Contour the hole
into the fitting for good flow. Screw on a "B" nut and stick it in the lathe is the
easy way. Tig weld the fittings onto the core. Wrap a wet towel around the end you
are to weld, so that only the area to be welded is exposed. Practice this on scrap.
Then just do it (or have it done). The core is soldered together so the need for the
wet towel. Keep the weld bead on the hex flats and leave the "B" nut on it to protect
the threads from the arc. As soon as you are done, cool with a wet towel. Weld a blob
on the 1/8" connector on the bottom and presto, a great oil cooler. Good for 200+
PSI. Mount it in foam lined clamps with screen door spings. Lynn E Hanover

 
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