How a Spinner II centrifuge works

The principle

A Spinner II centrifuge is self-powered: no motor, no wiring. Engine oil pressure drives it at over 6,000 rpm. It diverts a sidestream of oil, cleans it, and returns clean oil to the crankcase.

Oil enters the rotor under engine oil pressure, rising through a hollow shaft.
Centrifugal force separates the contaminants It reaches 2,000 times gravity.
The contaminants accumulate against the inner wall of the rotor, where they pack down.
Clean oil exits through twin opposing nozzles That thrust is what spins the centrifuge.
Oil returns to the crankcase through the level control base, which holds the flow needed to keep it spinning.

By mass, not by size

A cellulose-media filter stops whatever is larger than its pores. Soot is not: it passes through, or it plugs the medium. A centrifuge does not work on size but on mass — a particle denser than the oil is thrown to the wall, however fine it is.

That is why it captures soot and fine particles down to a tenth of a micron, and why its efficiency does not fade as it fills.

	Media filter	Centrifuge
Separates by	particle size	their mass
With soot	lets it through or plugs	captures it
As it fills	restricts	keeps its efficiency
At service	cartridge to buy and dispose of	you empty a dry cake

The numbers

2,000 ×gravity — the force applied to contaminants

6,000 rpmdriven by oil pressure alone

0.1 micronsize of particles captured

from 20 psioil pressure needed on HE models

6 litresdirt capacity of the largest model

1 million +engines equipped

Figures taken from Spinner II / T.F. Hudgins flyers and technical bulletins. Pressure and capacity vary by model — see each product page.

What it changes about servicing

No cartridge to buy: nothing to drain, crush or haul away.
The deposit comes out dry and compacted. Open, remove, close.
On disposable-rotor models, the rotor is replaced in one piece and discarded like an ordinary oil filter.
The deposit can be inspected: many use it to judge engine condition from one service to the next.
Capacity is such that it stays in service far longer than a filter.

What it does not replace

The centrifuge adds to the full-flow filter, it does not replace it. The installation bulletin is explicit: full-flow filters stay in place. The centrifuge works on a bypass, on part of the flow. If a bypass filter is already fitted, that is the one you remove.

Spinner II installation bulletin, « Oil Supply to Centrifuge » section.

Where it is already in service

The technology is not new: it equips more than a million engines. Spinner II centrifuges have been fitted as original equipment by every U.S. truck builder and by more than forty manufacturers worldwide over the past three decades. They are made in England by Mann+Hummel.

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