Cool Under Pressure: Supplemental Oil Pressure Can Save Your Engine

There is no denying, oil is the lifeblood of every engine. Whether it’s a tiny little 1.0-liter three-cylinder commuter engine, or a monster 1,008-cube Sonny Leonard behemoth big-block engine, without oil, both engines will turn into a paperweight in short order. Understanding that fact, it seems to be common sense that we should do everything in our power to keep our engines supplied with oil.

While that is a primary design goal of the engineers who design and build oiling systems, the fact is, things happen — especially when we modify or operate them outside of their original design envelope. Clearances open up, parts get damaged, internal components break — it’s just part of living in this imperfect world.

However, Canton Racing Products has set out to make sure that a single part’s failure doesn’t result in you bricking your engine. The Accusump oil accumulator has been around for quite a while, but isn’t “old technology” in any way, shape, or form. In fact, While the deceptively simple pressurized accumulator is the same as it was when introduced, modern electronics have given the Accusump an expanded range of installation and plumbing options.

The Basic Operation

First, let’s look at the basics of the Accusump, as the blue metal cylinder is deceptively simple. On one end of the cylinder is a gauge and a Schrader valve, and the other, either an electric or mechanical valve. However, if you were to cut the cylinder open, you would see where the magic of the Accusump actually happens.

Inside the cylinder, there are two chambers, much like a shock absorber. On one side of the piston is the engine oil, holding anywhere from 1 to 3 quarts of additional oil, depending on the model. On the other side is a volume of air at a specific pressure. In its most basic configuration — the mechanical valve — the side pressurized by air acts as a spring against the engine’s oil pressure.

Here are two common plumbing methods with the Accusump. The key takeaway from these is seeing how the unit feeds supplemental oil to the components which need it the most in the event of a loss of oil pressure. While these diagrams show a mechanical valve, the electric valve wouldn't change the plumbing at all.

As engine oil pressure rises, that “air spring” compresses until the air pressure matches oil pressure, making room for oil in the accumulator. As engine oil pressure drops, the air spring expands, pushing some of the oil in the accumulator back into the engine. If there is a sudden pressure drop in the oiling system, say from a failed oil pump or a pickup running dry, the Accusump delivers its reserve of oil to the engine, while, hopefully, you respond appropriately to the sudden loss of oil pressure.

All in all, a simple, effective system to buy you precious engine-saving seconds in an otherwise catastrophic event. However, Canton realized that while this system is effective in motorsports where load and pressure are relatively constant — like drag racing or circle-track racing — the system had some potential shortcomings in areas where oil pressure was constantly fluctuating, like on the street or a road course.

“In those applications, there is a lot of transitioning [laterally and fore/aft] and your oil pressure is constantly fluctuating,” says Iann Criscuolo, sales and marketing manager and technical department for Canton Racing Products. That constant fluctuation in pressure means the volume of oil in reserve is constantly in flux, as well.

“If you need the system during a period of low pressure, with the mechanical system, you’ll have a reduced volume of oil available to you at the most critical time. In drag racing and circle-track racing you’re usually at a pretty steady oil pressure and it’s always there,” says Criscuolo.

The manual valve is a simple on-off affair. When closed, it's closed; when open, it allows oil to flow in two directions through the valve. This works best in situations that feature a lot of constant load. Since this is a two-way valve when open, it constantly matches the engine oil pressure, and if oil pressure were at a low point when the Accusump was needed, the available reserve would be less than at full-charge. The remote valve opening and closing kit on the right is available, but is still less convenient than the electrical valve.

Electricity Makes Everything Better

To combat the potential issue found with a mechanical valve, Canton developed an electrical valve system, which adds some cost and complexity, but also adds an additional layer of controllability to the Accusump. Broken down to its simplest form, the system performs identically in principle, but instead of a simple quarter-turn ball valve, a more complex electrical solenoid system controls the gates.

“We have three different kits that activate with different pressures,” explains Criscuolo. “There’s a 20-25psi kit, a 35-40 psi kit, and a 55-60 psi kit. The lower number is the threshold at which the switch will be activated and dump the [accumulator] pressure into the engine. Then, once the engine reaches the higher of the two numbers, it shuts the valve’s output side, and then acts as a one-way valve to refill the Accusump.”

In addition to constantly maintaining a full load of oil in reserve at peak engine pressure, the electric valve is also a convenience issue. “Since it’s electric, you don’t need to manually open and close the ball valve every time you start the car and shut it off. It does that automatically for you,” says Criscuolo.

While Canton does make a remote activation kit, which operates much like an emergency brake cable, the electrical kit removes the chore of remembering to actuate the valve, because it can be wired into any ignition-on source, be it key-on for a street car, or master ignition-on for a racecar. “In my personal opinion, the electrical valve is my go-to, mainly for the ease of use. It’s just so much easier,” says Criscuolo.

The electric valves are interesting pieces. In addition to running off of a pressure switch, it opens and closes the valve at a predetermined pressure value. However, the neat feature is, that when “closed” it still functions as a one-way valve, allowing pressure and volume to build in the accumulator, so you always have the maximum volume and pressure available in the tank.

Pre-Oiling — A Side Benefit

One of the functions of the Accusump system, which we didn’t really cover, is that it acts as a pre-oiler. Whether you’re using an electrical or mechanical valve, the valve is opened before the engine starts. Because an Accusump holds pressure indefinitely, as soon as you turn open the valve, the reservoir dumps all the oil into the unpressurized engine oiling system.

The New Kid: The Turbo Oiler

With the unmitigated success of the Accusump, Canton repurposed the smallest model, and then halved its size, to make two sizes of the new turbo oiler — 0.5-quart and 1 quart. It’s long been known that shutting down a turbocharger after it’s been run hard, with no cool-down time causes the formation of waste solids in the turbocharger’s oiling system.

To battle the buildup of this “coke” as it’s known, the old-school method was an electrical “turbo timer” wired into the car’s ignition system to keep the engine running after the car was shut down, in order to keep oil flowing to the turbocharger while the system cooled off. An ingenious system, if not slightly unsettling, especially in a street car, where you leave your car running for a specified period while you run into the Qwik-E-Mart to grab a Bladder Buster and some beef jerky.

Looking to accomplish the same thing, but without needing to keep the engine running, Canton developed the Turbo Oiler. Using a similar principle as the mechanical-valve version of the Accusump, but without a valve at all, once the engine is shut down and the engine’s oil pump stops making pressure, the Turbo Oiler releases a metered flow of oil into the turbocharger oil feed circuit.

Similar in function to an Accusump, the Canton Turbo Oiler offers a supply of oil to the turbocharger for up to a minute after the engine has been shut off, giving the turbo precious time to cool down.

By maintaining that flow of oil to the turbocharger once the engine is off, the turbocharger’s rotating assembly is given time to cool off, while still receiving oil pressure and flow. This not only protects the bearings while the wheels spin down, but helps prevent the buildup of coke and other contaminants that form after shutting down a turbo without a proper cooldown period allowed.

Additionally, the Turbo Oiler provides the same protection to the turbo that an Accusump provides to the engine, in case of a loss of oil pressure. However, that feature should be used in conjunction with an Accusump, otherwise, you’ll just save your turbo, while your engine starves for oil.

Regardless of what form of driving you are doing with your vehicle, Canton’s Accusump products can give you precious seconds to save your mechanical investment in the case of an oiling system failure. In the case of the Turbo Oiler, you can also protect your turbocharger every time you shut down your engine, not just in case of a system failure. Either way, you’re buying insurance for your engine.

Article Sources

About the author

Greg Acosta

Greg has spent fifteen years and counting in automotive publishing, with most of his work having a very technical focus. Always interested in how things work, he enjoys sharing his passion for automotive technology with the reader.
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