<VV> Lifter Tester - BT59 Oil....

[Western Canada CORSA]

One of our members came across a Lifter Leakdown tester.  It is basically a
cup full of oil you put the lifter in, and a probe with a weight with a
gauge puts pressure on the lifter once it is pumped up.  You then measure
the time each lifter takes to bleed down while rotating the cup.
 
It specs "BT-59" oil for doing the test.  Anybody familiar with this oil and
what a modern equivalent would be?
 
Regards,
Joel