[TR] [6pack] TR6 Oil Cooler

[Robert M. Lang]

Hi,

Whether you need an oil cooler is subject for debate. Going out on a limb 
here, a street driven motor would probably never see critical oil temps, 
hence the oil cooler is not needed. If, on the other hand, you have a race 
motor that sees high-rpm, heavy load operation, then the oil cooler would 
be called for. The one exception for a street-driven car would be if you 
tow or you plan to sit in traffic all the time.

As a single data point, I have a 12:1 motor in an autocrosser and I do run 
an oil cooler. With no oil cooler, I would see oil temps in excess of 210 
on a hot day. With the oil cooler I do see up to about 180 when it gets 
really hot and I have two drivers and there's an occasional spike to 
200-ish. So the delta T with a 13-row cooler is 10 - 30 derees oil temp. I 
have a 13-row cooler and I have a thermostatic bypass valve.

But to the point - with an oil cooler and the old-style oil (20w50), 
you're giving up horsepower due to parasitic drag from the oil. There are 
other side-issues that are related to the oil being too cool.

I guess the point is, there's not much to be gained by the oil cooler 
except possibly the ooh-ahh factor. In any case, if you do run an oil 
cooler make sure that you have one of the thermostatically controlled 
bypass thingies because if you don't run one of those and you run your car 
when it's cold the oil will NEVER get to operating temps and you'll be 
bypassing the pressure relief valve all the time because the oil pressure 
will STAY at 100+ psi all the time. This is patently bad, IMHO. Also note 
that you are adding a maintenance item to your system...

regarding maintenance of an oil cooler, with a thermostatic bypass, you 
need to test the thing to make sure it's actually working, so add that to 
your monthly to-do list. You also need to keep a sharp eye on the cooler 
and hoses for problems. The oil flows through the system at line pressure, 
so a tiny crack in the cooler itself can turn into a gusher at (usually) 
the worst time. There's also the issue of purging the oil cooler during 
oil changes so that you get a full, fresh charge of new oil during oil 
changes... which is one of the points of doing oil changes.

But that's my two cents on the matter. Like I said, I have one on the race 
car. I don't have one on the street car.

c ya,
rml
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Bob Lang              Triumph TR6!!            |  This space for rent
Former NER Solo Chair                          |
Voice:617-253-7438                             |  Cell: 339-927-4489
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