Hmm, this got rather long; I guess I've learned a lot about oil coolers
over the past few years, adding them to two Triumphs, with two more cars in
line to get them...
I fitted an oil cooler to my 4A about two years ago. I used the
thermostatic kit from Moss Europe/Triumphtune and had some trouble with it.
If I were to do it again, I'd buy the pieces from various vendors and make
up the lines myself.
(In fact, I did this for my GT6+, mentioned briefly below; if anyone wants
the details I'll be happy to share them separately.)
I removed the radiator "shroud" - the steel hunk that tries to protect the
lower end of the radiator - and replaced it with one from a TR6. This had
two benefits: it already had holes to mount an oil cooler (this puts it in
front of the lower portion of the radiator, behind the valence and below
the bumper) and it had holes for a front anti-sway bar which I also wanted
to mount. I bought a used MGB cooler from someone on the net, and mounted
it with rubber shock mounts in the existing holes. It wouldn't surprise me
if you could use the same trick on a 4, or make up a bracket to support the
cooler there.
I ran with the cooler that way for about half a year, and decided that I
really wanted it to get fresh air; I could still see the oil pressure
drooping more than I wanted. So I cut three holes in the valence, about
3x3, and trimmed them with chromed plastic motorcycle fairing edging
(thanks John). The holes are mostly hidden by the bumper, and actually look
quite nice, if I do say so myself. The 250 and 6 came with a large hole
stamped into the valence for this purpose.
The other scheme I've seen used (on a 3) is to build a fin/wing (he did it
out of marine plywood) that extends below the valence and directs air back
up into the cooler. This would work, but it's vulnerable to curb crashes.
If you're not having problems with marginal cooling, mounting the cooler in
front of the radiator will not be a problem. That section of the radiator
is out of the air stream anyway! If you're really concerned, you could make
up a shroud to enclose the area between the cooler and radiator. The
problem is mostly turbulence caused by the extra obstruction in the
airstream. If you're not racing and your radiator is in good shape, this
shouldn't be a problem.
If you're in to fabricating, you could build a bracket that hangs on the
side of the radiator frame, and put the oil cooler there. I did this on my
GT6 (because there the radiator *is* marginal). This is a fair bit of
fiddly work to get right.
For some reason the Serck/Mocal coolers are *very* expensive - look for a
used MGB cooler (I think I paid $35). If you have to buy new, shop around.
Racer Wholesale has a line of oil coolers that are made in Canada and don't
mount quite the same way (wouldn't fit the shroud mentioned above without
some work) but cost about half as much. Unfortunately, they have 1/2 NPT
female fittings instead of 1/2 BSP, so you'll need an adapter if you buy a
complete line kit, or you need to take this into accound when making up
your own lines.
Now, the adapter. I had some problems here - a long time ago I bought a
spin-on adapter to replace the cannister filter (a great thing to do, btw).
When I bought the adapter/thermostat/lines from TriumphTune, it turned out
that their adapter was machined such that it didn't quite fit the spin-on
unit properly and wouldn't seal. So I had to do some work on it in the
lathe to make everything fit right. Beware this; consider buying both parts
from the same place and make sure you can return it if it's not right.
There are two kinds of adapters, btw: one fits between the block and filter
head, and the other between the head and filter proper. Current wisdom
seems to prefer the latter, because the relief spring is in the "circuit"
before the oil cooler, so you can't overpressure the cooler when the oil is
cold and blow it out. It's probably also less fiddly to fit in a tight
engine compartment.
I like having an oil thermostat, for the same reason - it protects the
cooler. It also gives me an additional place in the lines to open them up
and drain oil from the cooler, if I really want to. I usually don't bother.
If you make a custom mount for the cooler, you could arrange to have at
least one fitting at a low point to facilitate draining. The oil coolers
aren't all *that* fragile; just make sure to use a backup wrence.
You can buy all the pieces you need to make up the lines from Dave Bean
Engineering, among others. TRF sells complete kits that are probably quite
nice. If you want to buy individual pieces (most of this stuff is cast by
Mocal and just resold/repackaged) I highly recommend BAT Industries in
Florida; they seem to be a direct Mocal importer and know what they're
talking about.
A new bit of technology is using an oil-to-water intercooler; the theory
here is that the radiator has enough cooling capacity to cool the engine,
so using some of that capacity to cool the oil directly instead of by
conduction through the block is a win. I don't know of any off-the-shelf
setups that will work for our cars, but I could imagine taking an oil
cooler adapter and doing a little custom plumbing into the water pump or
heater return line (hmm, some problems there) and having a neat
installation.
Good luck. Adding an oil cooler is well worth it on our cars - one
statistic I remember hearing is that every 10 degrees you lower the oil
temp adds 10% to the life of the engine.
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