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This is a Billet Fabrication oil pan. As you can see, the pan looks like any other well-built aluminum drag race pan from the outside. On the inside though, are a series of "baffle" balls used to positively control oil during acceleration and braking. More in the next photo: |
Wet sump oiling systems are the most common in drag racing. Virtually every Stocker and Super Stocker uses one, and so do plenty of Super Class cars, Competition Eliminator cars along with countless bracket cars. And we’re not even taking into consideration the virtual plethora of fast street cars. They're also used with certain exclusivity in production cars. After all, wet sump systems are relatively inexpensive, uncomplicated and for the most part do the job they were designed for. Unfortunately, wet sump oiling systems aren't perfect. That's why so many unlimited cars in all forms of racing incorporate rather expensive (and often equally complex) dry sump systems.
 The check ball baffles are situated in the same location as a conventional swinging trap door inside the oil pan. Jeff Johnston's research has shown that the conventional trap doors do slow down the movement of oil from the rear of the pan, but a considerable amount of lubricant still manages to escape by way of partially open doors. This check ball arrangement positively shuts off the flow of oil out of the sump area. In turn, this allows all of the oil to remain in the sump during braking. As the baffle ball slams forward in the baffle tube it seats against the end of the tube (which is constructed with a built-in internal step). This seats the ball, and prevents oil from rushing forward. Under acceleration, the ball slams rearward. The back of the tube is open and oil can fill the sump. |
One of the biggest drawbacks in a wet sump oiling system is the physical control of the lubricant. When the car moves, the oil moves. That means when you hit the throttle, the oil rushes to the back wall of the oil pan and sometimes tries climbs up the back of the engine block. When you hit the brakes, then the oil surges to the nose of the pan, often draining the sump in the process. Drag racing amplifies the dilemma. How? That's easy. Each time you perform a burnout, the oil moves rearward. Then, as you hit the brakes, it moves abruptly forward. If you race in an index or break out category, there's always the possibility of hitting the brakes hard at the big end of the track. The results are usually quite predictable: An empty or near empty sump and an oil pressure gauge making an abrupt swing to the left. The traditional way to control this oil migration is the installation of swinging trap doors and baffles inside the pan. They work, but in many instances, they're just a Band Aid (particularly if the trap door configuration proves inefficient). When the Band Aid doesn't work, then one thing happens: The oil pressure gauge drops like a rock. Bearings run dry. And eventually, your wallet becomes lighter. Often much lighter.
So what's the fix? A very well designed pan is one answer. Another is a high tech, reliable oil pump of some sort (we’ve recently addressed that with a look at Titan’s gerotor oil pumps). Is there anything else? One company that follows a less traveled path toward oil control is Jeff Johnston's Billet Fabrication. Basically, Johnston completely re-thought the swinging trap door arrangement and came up with a series of internal oil pan check balls to stop the oil migration. Johnston has also addressed methods of “pulling the pan” to inspect the bottom end and also has some very interesting views on windage trays. More on those later. First, lets take a look at the unique baffling:
Pans with Balls?
Jeff Johnston took a unique approach to resolving the "low or no" oil pressure problem with wet sump oil pans. Shop experimentation and considerable track testing (using a video camera focused upon the oil pressure gauge) led Johnston to believe that the conventional trap door baffles found inside oil pans allowed more seepage than previously assumed. Johnston and the Billet Fabrication crew found that the conventional trap doors do slow down the movement of oil from the rear of the pan, but a considerable amount of lubricant still manages to escape by way of partially open doors. This philosophy led to the development of the check or "baffle" ball system, which Billet Fabrication claims positively shuts off the flow of oil out of the sump area. In turn, this allows all of the oil to remain in the sump during braking, which in turn, allows the engine to maintain oil pressure.