This afternoon Denise Thorpe (thorpe@kegs.saic.com) requested info and
opinoins about a four row radiator core for an MGB, and I volunteered my
experience to his private box. This was his response:
Subj: Re: Four row radiator core!
>Date: 96-05-17 18:44:34 EDT
>From: thorpe@kegs.saic.com (Denise Thorpe)
>To: BarneyMG@aol.com
>
>Barney,
>
>Please post your very informative answer to the list or give me
permission to.
>You have tricks I've never heard of before. Maybe I'll do all that stuff
next
>radiator. :-)
>
>Denise Thorpe
He must have been impressed. OK Denise, I'll make it public.
So here I quote myself:
Hi Denise,
I've had a four row radiator core in my MGA for a couple of years now. It
works great, and it wasn't a big deal for the shop to put it in either. But
it did take several tries at different shops before I found one that would
cooperate. I believe that most think if it ain't stock it's too much bother.
My original radiator core didn't even have tubes as you think of them. It
was made up of a stack of flat pieces with slots extruded and all pieces
soldered together. And the top and bottom tank joints were a joke.
The original MGA radiator was designed to cool adequately under normal
driving conditions, and it does (just barely). Under normal driving the
temperature seldom goes much above 190 degrees. On the other hand, My MGA
tows a small trailer at 75 MPH in extremely hot weather, and it does that a
lot! I used to have cooling problems, but no more. I had a local radiator
shop replace the original cooling core with a newer VT style (vertical tube)
core with many close set tubes and lots of very fine copper fins between.
This has more water flow capacity, so the water stays in the core a bit
longer. It also has much more surface area on the fins, so it transfers heat
to the air much better.
An additional change to the radiator involved the shape of the solder joints.
The original design had horizontal solder joints between the core flanges
and the top and bottom tanks. These soldered joints are in tension loading
and tend to separate and start to leak with just a little pressure and a lot
of vibration. The original radiator pressure cap was only 4 PSI, and the
optional replacement cap is 7 PSI. That's about all the pressure the
original radiator design can take without blowing apart. I had the shop
reform the flanges on the tanks and the core so they are now verticle and the
solder joints are in sheer loading (much stronger). After soldering, it was
pressure tested at 25 PSI. Now I can use a 13 PSI cap if I want to, but
there is really no need for that, it cools great with the 7 PSI cap.
Another change was to replace the original water neck which is 1" deep with
the newer style neck which is only 3/4" deep. For this there is a better
assortment of pressure caps available, including coolant recovery type caps,
which have a second seal at the top flange. I also had them shorten the
overflow tube to about 1", and installed a small hose running to an added
coolant catch bottle. With this I can keep an eye on the coolant level
without ever removing the pressure cap. It also makes the autocross clubs
happy that the MGA doesn't spit coolant on the track any more.
I think the whole job on the radiator set me back about $180 US -- a very
reasonable price considering the peace of mind that comes with it. Let me
know if this helps put your mind at rest about the conversion.
Cheers,
Barney Gaylord -- 1958 MGA
Naperville, Illinois
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