Oil is literally an engine’s lifeblood, and it only takes a few moments of pressure drop to kill the main bearings and wipe the cam. Racers go to great lengths to prevent that kind of disaster; from deep, kicked-out sumps, to baffles and windage trays, all the way to full dry-sump systems. All of these strategies have their strengths, but none of them can start the oil flowing before the oil pump begins to turn, or provide a few precious seconds of full pressure to shut down the engine if you manage to put your car on its roof. There’s only one technology we’re aware of that does all that – Canton Racing Products’ patented Accusump oil accumulator.
The Accusump is simple and ingenious – it’s a reservoir divided into two sections by a piston. On one side, oil is accumulated, and on the other, trapped air acts as a spring to keep that oil under pressure. It’s totally self-regulating, with the oil side filling and emptying in response to the pressure in the engine’s oiling system. In its simplest form with no valve, an Accusump serves as a surge tank that fills in the gaps in engine oil pressure by pushing oil back into the system, then refilling when the system pressure comes back up. But in conjunction with a manual or electric valve, it becomes even more versatile.
“The Accusump is the original automotive oil accumulator,” explains Canton’s Mike Zeranski, Jr. “It was designed in the late 1970’s to address the growing oil control problems found in road racing applications. The concept of an accumulator to store a reservoir in order to equalize pressure surges was something that had been long used in industrial applications. The Accusump’s inventor took those concepts and created the Accusump as the first accumulator designed to be used for oil surge in automotive applications. Canton acquired the Accusump brand from the founder in the early 1980’s and worked with him to improve that original design.”
The system has found its way into all sorts of different places, from street to race and even marine engines. “I can”t remember all different applications that the Accusump has found itself in over the years,” Zeranski admits, “but one that sticks out is aerobatic planes.” Anything that can provide oil pressure for extended inverted flight will be more than sufficient for any earthbound application. Follow along as we demonstrate how easy it is to install this engine-saving piece of hardware.
Canton provided a 2-quart capacity Accusump reservoir, standard electric control valve, sandwich-style oil filter adapter, and all the requisite plumbing.
For our installation, we requested a two-quart capacity Accusump, an electric control valve, and a sandwich-style oil filter adapter. The reservoirs are available in 1, 2, and 3-quart oil capacity, and a longer 3-quart version that has more air capacity for high-pressure applications. Canton recommends the 2-quart for small-block V8, V6, and 4-cylinder applications, as well as a pre-oiler for all engines. We chose the electric valve for convenience – if the reservoir or lines are mounted within reach of the driver, a manual valve is also an option. With either type of valve, the idea is to close off flow before shutting down the engine to store pressurized oil, then open the valve for pre-oiling just before starting it again. The electric valve automates this process when wired into an “ignition hot” 12V circuit. A third option is their electric pressure control valve system that incorporates a sensor that only allows the Accusump to discharge when engine oil pressure drops below a predetermined range, and only fill when the pressure rises above that level.
“The standard electric valve is great for street applications and even drag where the Accusump’s need for discharge is infrequent,” says Zeranski. “It refills at a more gradual rate and an takes about 30 seconds to a minute after a discharge to be fully refilled and ready for another discharge. The EPC versions of the electric valve include the standard electric valve but are controlled by a pressure switch which will turn the valve off when it senses pressure above its given setting. By turning the valve off, it no longer attempts to discharge oil and thus can more rapidly refill. Because of the valve’s quicker refill rate it makes a good option for road race and other applications where the Accusump is expected to cycle several times in a short period of time.”
- Accusump 2-quart oil accumulator (PN 26-026)
- Accusump Electric Valve Kit (PN 24-270)
- Accusump Mounting Clamps (PN 24-200)
- Accusump Install Kit for 3/4-16 thread and 2 5/8-inch gasket (PN 24-726)
Plumbing in the system can be done in several ways. If you’re already set up with an external oil cooler or remote filter, it’s just a matter of putting a t-fitting into the external AN lines, but in our case an oil filter adapter was the easiest way to connect it all up. Canton offers a range of adapter kits to fit pretty much every common oil filter thread/gasket combination, in both inch and metric sizes.
The first step in installation is deciding where to put the Accusump reservoir. Our 2-quart model measures 4.5 inches in diameter and 12 inches long, not including the valve assembly or pressure gauge. We fabbed up a pair of aluminum brackets to mount ours ahead of the radiator support.
Canton makes it very clear that the clamps can only be placed on the very ends of the reservoir. Putting them towards the middle of the tube can crush it and prevent the billet aluminum internal piston from moving properly. The interior of the aluminum body is Teflon hard-coated.
Though the system is pretty much maintenance-free, should it ever need to be serviced, it’s a pretty easy process. Per Zeranski, “We see Accusumps that are decades old still in service. One of the great things about the Accusump is its relatively simple design with few parts to wear or break down. As long as your oil is kept clean and filtered the Accusump will last about as long as any other part on your car. When they do get dirty from oil sludge or because of an engine problem, we do offer an inexpensive rebuild service.”
T-bolt clamps secure the body of the Accusump in place. Canton suggests mounting the Accusump in such a way as to put the oil fitting on top - that way any air in the system will get purged during pre-oiling, when bubbles in the oil won't cause a problem. Space considerations dictated that we mount ours horizontally, but it will still purge properly; it will just take a few more fill/empty cycles.
Before screwing in the electric valve, we temporarily removed the oil pressure relief valve. This valve is set to open at 175 psi, far higher than the operating pressure of the system, to prevent the reservoir rupturing should it become hydrolocked due to improper setup or being placed too close to an intense heat source.
The electric valve gets installed via a 1/2-inch close nipple, using Teflon tape to seal the threads. Follow the instructions and don't try to use Teflon paste or pipe dope - don't ask us how we know this...
With the valve attached, the Accusump gets clamped in place.
The sandwich adapter goes between the block and the oil filter, and an AN fitting screws into the adapter.
The adapter kit includes braided stainless line and hose ends - after measuring for the proper length (and allowing some slack for engine movement) we cut and assembled the oil line.
With all the plumbing connected, the next important step is to bleed the air reservoir down to the recommended 8-10 psi with the oil side empty.
With the physical installation complete, we moved to wiring up the electric control valve.
Wiring up anything electrical is the bane of many an otherwise mechanically-inclined racer, and we’ve been known to occasionally produce tangled bundles of unmarked black wire instead of tidy, well-labeled harnesses. To avoid that with our Accusump installation, we turned to Painless Performance Products and their Cirkit Boss 3-circuit fuseblock system (PN 70113) to provide a clean, organized way to provide 12-volt ignition-switched power. It’s not just an issue of obsessive/compulsive disorder, though – the Cirkit Boss gives fused protection to up to three 10-amp circuits, guards its main power relay with a fuse of its own, and defends the whole shebang with a 40-amp circuit breaker on the primary power lead. Overkill? Perhaps, but if you’ve ever had an electrical fire, you’ll appreciate the defense in depth against a short circuit. The Cirkit Boss kit comes with taps that let you run the control lead off of any type of automotive fuse block, making installation easy even for the electrically disabled.
To simplify the wiring, we turned to Painless Performance Products' Cirkit Boss relay/fuse assembly, which can provide ignition-switched power for up to three 10-amp circuits.
The individual circuits are protected by 10-amp fuses, the relay has its own 5-amp fuse, and the main power feed is isolated via this 40-amp circuit breaker. If you have a healthy fear of electrical fires, this setup is serious peace-of-mind.
One of the really nice things about Painless' kits is that they print tracer labels on all the wiring for easy identification.
With the fuse block in place on the shock tower and the relay wired into an ignition-hot trigger, the installation was complete.
Turn the ignition on, and the valve opens. Once the engine is started, oil begins to fill the reservoir and the air pressure on the other side of the piston begins to rise, eventually approximating the engine oil pressure. Turn the ignition off, and the valve closes and traps pressurized oil inside the Accusump, ready to be released on the next cold start.
Don’t forget to top off the oil after charging the reservoir, and remember to activate the valve to drain the Accusump back into the engine prior to changing the oil. Zeranski offers the following tips for installation and use; “The Accusump is fairly simplistic in its installation, but we still get calls every day troubleshooting installations. Of course, we recommend reading the 10 page instruction manual that comes with the Accusump from cover to cover. However, knowing not everyone does that, some key things to remember are to make sure all the fittings are tight and to check the system’s pre-charge of air pressure at the back end of the Accusump on installation. The Accusump relies on its ability to hold its pre-charge of air pressure, a small leak here or incorrect air pressure can affect its performance.” Zeranski adds, “Another main area of focus is the valve install. The elective valve is designed to flow in a specific direction, so it is important to install it in the correct orientation.”
In an afternoon, we installed, plumbed, and wired the Accusump, giving our engine automatic protection against dry starts and oil starvation should the pump pickup get uncovered. We can expect extended engine life both due to the pre-oiling function helping to eliminate normal wear and tear, and avoiding catastrophic damage in the event of a problem with the normal oil supply. Either way, the Accusump is a cost-effective way to protect your investment in any engine, at the track or on the street, and the addition of the electric valve system makes it a no-brainer – turn on the ignition, and you’re protected. Save one race block and you’ve paid for the setup five times over.