Racing Oil Pans - A Baffling Experience

A New Oil-Pan System Cures Pressure Drop Caused By Deceleration And Hard Braking

Sky Wallace Jun 1, 2000 0 Comment(s)
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Here, the Baffle Ball concept is clear for all to see in this dummy baffle (the production versions replace the cotter pins with a welded-in rod). The 3/4-inch-diameter balls are held captive within the specifically-shaped, conical interior of the tubes; the oil flows freely around them in the open position, but is sealed tightly in the rear sump when the balls roll forward during braking.

At first glance, it seems a bit of a stretch to link the pouring of concrete with the latest development in oil pan technology, and the involvement of four high-tech-inclined industry powerhouses in a joint effort to help solve a common problem, but stick with us here and we'll run it down for you.

As the namesake of Jeff Johnston's Billet Fabrication, Jeff Johnston has long been pondering a situation that many wet-sump, high-horsepower cars experience. Both after the burnout and at the end of a pass, when the binders are applied, the oil pressure drops as the oil slams toward the front of the pan and away from the pump. Internal pan baffles and their "trap doors" have been an integral part of race-engine oil pans for years, but still the problem has persisted.

Some racers get around the top-end pressure-drop problems by simply shutting off the engine right at the finish line, which causes another segment of the racing fraternity to shudder. John Gianoli, proprietor of Reggie Jackson's Performance Engines (San Bruno, California) is in this group.

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This shows the forward-facing look of the Baffle Ball tubes. Jeff Johnston built this demonstration pan for use at the PRI Trade Shows; it features a standard trap-door baffle at the other end for easy, visual comparison of fluid flow using the two methods. An O-ring fits in the channel seen along the top, and a clear shield was bolted on to keep the fluid in place during the repeated back-and-forth sloshings.

"If someone is running an automatic transmission," Gianoli told us, "and it isn't adjusted properly, the trans can easily go into reverse when the racer puts it into neutral. This is obviously bad enough, but another result can be even worse. If the rear is set up with ladder bars, the front rod ends of the bars often break off at this point, and then the car crashes."

And, no matter what one does at the top end, that still leaves the burnout to deal with. Killing the motor at the end of a burnout is obviously not an option. Letting the car drift downtrack for a while after getting off the throttle and slowing very gradually, in hopes of keeping the sloshing oil from getting too upset, can sometimes be marginally effective, but again is far from ideal.

As a builder of aluminum, billet-railed, high-performance oil pans and valve covers, Johnston has long pondered possible cures for this oil-control problem. And he's had many conversations about the subject with Bob Sanders of Titan Speed Engineering (Ojai, California), manufacturers of wet-sump oil pumps for the racing industry. Billet Fabrication builds pans designed to accommodate the large Titan pumps, so Jeff and Bob have many opportunities to chat. They had spent some time brainstorming possible solutions, but hadn't yet come up with any answers.

And so one weekend day, late in the 20th century, Johnston was helping a friend pour some concrete. While idly watching the mixture flow out of the hose from the pumper truck, he became intrigued by the operation of the 4-inch check balls that, simply and efficiently, governed the movement of the ooze from the two-stage pump and kept it going in the intended direction.

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This is the actual Billet Fabrication aluminum stroker pan that was used on Steve Collins' big-block Chevelle during the intial on-track testing of the Baffle Balls.

The proverbial light bulb lit up over Jeff's head, marking the beginning of some frenzied activity for Billet Fabrication. Phone calls were made, and a few days later, he had some new steel balls to work with.

A bit of time was spent at the computer, and a spew of commands was sent to the in-house CNC machinery. One thing led to another; before long, a seemingly optimal cylindrical device was in his hands. Billet-carved and featuring an interior that sports a cone at either end, it is shaped to accept a caged, 3/4-inch steel ball in one side that stops the flow of oil when the ball is forced forward, while allowing controlled fluid movement at all other times. (The actual dimensions and shapes of the tubes were the result of both mathematical equations and actual testing.)

And this ball slams shut tighter than a woman's purse in New York's Central Park. In other words, this valve arrangement seals really well.

The next steps in the process led to a test pan, with a half-dozen of these check-ball assemblies welded side by side into a baffle, just a bit above the pan floor. A standard trap-door baffle was installed at the other end of the pan, to provide a good look at the difference in the two methods of oil control.




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