Harvest King dominated this comparison, and it
costs $10 a gallon — $2.50 a quart. It gave up the least chain wear at 1.89
mm, held the bar to 250°F when the hottest oil reached 310°F, flowed the
track in 3.39 seconds at room temperature and 18.5 seconds after a day in the
freezer, and finished second on film strength at a 6.98 mm scar. It is
genuinely tacky, it clings to the chain, and it beat oils costing nearly three
times as much on almost every measurement that matters.
The Mobil Delvac SAE30 motor oil finished second overall at 2.3, and its
result is the most interesting one here. It won the film-strength test at 6.34
mm and carries 3,930 ppm of detergent and dispersant against 13 ppm for
Harvest King, so it will keep an oiler cleaner and it protects superbly under
load. What it lacks is tack: it slung off the chain, smoked heavily, and the
chain had stretched enough to need retensioning after two minutes of cutting.
As an emergency substitute it works; as a permanent choice it does not. Oregon
took third at 2.6 and is the pick for hot, heavy work — it smoked the least of
any oil in the cutting test, lost only 0.41 g after two hours at 330°F, and
placed second in chain wear at 1.95 mm.
The cautionary results sit at the top of the price list. Husqvarna, at $25,
smoked heavily within five minutes, ran the hottest bar at 310°F, and produced
the most chain wear at 2.22 mm. Stihl Platinum, at $26, has excellent tack and
good heat resistance but the thinnest anti-wear additive package in the group,
which produced the largest lubricity scar at 9.46 mm and the slowest cold flow
at two minutes flat. Echo, at $27, sat mid-pack everywhere. If oil flow is
discounted entirely as a criterion, Harvest King still comes out on top, with
Oregon and Mobil Delvac tied behind it — so the outcome does not hinge on how
much weight the flow races are given. Buy on measured wear protection and heat
resistance, not on the badge or the shelf price.