Keeping a steady supply of oil flowing can be a challenge in racing applications
By Larry Carley
“Energy Recovery” Oil Pump
Every oil pump needs a bypass valve to vent excessive pressure, otherwise bad things might happen to the pump or engine if oil pressure was not controlled. But every time excess oil pressure is vented through a bypass valve it represents lost energy. Verne Schumann of Schumann Sales & Service has come up with a way to recover much of this lost energy with his newly patented “Energy Recovery” oil pumps for SB/BB Chevys and Fords.
Schumann said the new “ER” design “diminishes the input effort required, yielding the same gallons per minute (gpm) volume and pressure as high-effort pumps. Normal internal hydraulic pump by-pass lock-ups are eliminated. Unique energy recovery engineering converts spent energy into active input oil supply flow.” Schumann said his new ER pumps are 30% more efficient and significantly reduce the power needed to drive the pump.
Schumann is not making any specific horsepower claims for his pumps, but on one dyno test, an engine showed a 10 to 15 hp improvement by simply changing the oil pump. Schumann’s Energy Recovery pump uses an external hose to connect the bypass valve discharge port to the pickup tube. By rerouting oil back into the pickup tube, the oil pressure that would otherwise have been wasted is reused to feed the pump. It has a siphoning effect that improves oil flow into the pump and reduces the chance of oil starvation when the engine is accelerating hard or is experiencing lateral G-forces.
Chevy LS Oil Pump Issues
The front mounted oil pumps on Chevy LS engines have been a challenge for many engine builders. The pumps on these engines have critical clearances that require the pump gears to be precisely centered with respect to each other and the pump housing. The recommended procedure is to mount the oil pump with the block out of the vehicle sitting upright with the crankshaft in a vertical position so the crank will be centered in the main bearings.
Shims must then be positioned between the inner and outer gears, and the outer gear and housing before the four housing bolts are tightened down to secure the pump to the block. If this procedure is not followed, the oil pump may bind and/or break as soon as the engine is cranked or started.
The stock pump housing can also be easily distorted if it is clamped in a vice, causing the pump to bind when it is installed on the engine. Schumann makes a special work fixture that allows the LS pump to be held securely without bending the housing.
Mike Osterhaus, Product Development Manger for Melling said the front mounted oil pumps on many late model engines has created opportunities for engine builders because many original oil pumps cannot meet the demands of a performance engine.
He said Melling’s line of “Select Performance” oil pumps eliminates those issues while supplying increased performance and durability at an affordable price. Osterhaus said that aftermarket oil pumps for the Chevy LS engine and similar applications are available from a variety of sources, but that many of those offerings are based off original equipment oil pumps.
“The original equipment pumps cannot compete against the performance and durability of a Melling performance oil pump, which was designed from the start to be used in performance engine applications.” He said improvements include increasing the pressure tightness of the pump assembly to reduce oil leakage.
Crank-driven pumps have larger surface areas which need to be sealed. Reducing the leakage coming from the pump results in improved oil quality and flow delivered to the main gallery. The pumps are also cast in 356-T6 aluminum, precision CNC machined and hard-coat anodized for improved durability.
Galling can also be a problem in some applications, such as GM 5.3L, 6.0L and 6.2L V8s. A severe galling condition can arise from the tolerances and materials used in the original GM oil pumps. This situation cannot occur in the Melling oil pumps because of changes that have been made in the design of the pump itself. “Our high-volume 10296 performance pump for the Chevy LS flows 18% over stock, and delivers improvements in flow and pressure across the entire engine operating range, not just at hot idle.”
Another option for the LS is to eliminate the stock front mounted gerotor pump altogether and use an external oil pump. TJ Grimes of Baker Engineering/Pro Cam said his company makes a Chevy LS wet sump oil pan conversion that retains a wet sump setup but uses an external pump like that from a dry sump system to supply oil to the engine.
The oil pan is only 6-1/2˝ deep but is 13˝ wide and holds 7 quarts of oil. The modification requires blocking the oil ports for the original front-mounted pump. The conversion eliminates the long pickup tube that can delay flow to the stock pump and reduces the risk of oil starvation.
Grimes says the trend is to make wet sump oiling systems work like a dry sump system but without the cost or complexity of a full dry sump system. “You can keep windage down inside the crankcase by using scrapers to pull oil away from the crank.”
Dry Sump Systems
With dry sump oiling systems, the setup is entirely different than a wet sump system. Most dry sump systems use one to four or more scavenge pumps to suck oil out of the pan (and other locations on the engine), and one or two pressure pumps to feed oil back into the engine. Oil aeration is controlled by using an oil/air separator and routing the oil into a vertical storage tank before it is pumped back into the engine.
The tank adds additional oil-holding capacity to the system to help keep oil temperatures down. The external plumbing makes it easy to add an external oil cooler as well. Pulling oil and air out of the crankcase also increases horsepower by reducing windage and drag on the crankshaft. The only drawback with dry sump systems is their cost, which can range from $1,500 up to $3,500 or more, depending on the setup.
Bill Dailey of Dailey Engineering says his company specializes in high-end custom dry sump pumps and pans for racing applications. “A lot of people sell off-the- shelf components for dry sump oil systems. We do too. But many racers want special mountings or designs to fit their specific race car. So most of what we do is custom work for racers.”
One such product is a custom billet oil pan with an integral oil pump. “They won’t allow it in NASCAR, but where rules allow it, the setup provides a smaller and cleaner installation,” said Dailey.
What kind of oiling system you ultimately decide to use in an engine you are building will depend on the application, your customer’s wishes and how much money he is willing to spend to keep his engine lubed. Lubrication is one area where you don’t want to take chances.