The oil pump is the heart of any motor, pushing the blood-oil-through the motor to keep it alive and running. Just like the human body needs blood moving through every vein and artery, so does an engine. So it goes without saying that if you have a good pumping heart, you feel alive and well. The same goes for an engine: The more oil a pump can push, the better-performing, more efficient the motor will be. As we all know, the H-D oil pump works well, but as with anything out there, maybe someone is improving on a good thing. The team at Feuling Oil Pump Corporation feels the same way we do: The more oil you can move through the motor, the better the motor will be. So they have come up with what they are calling the "Balanced System."
Feuling Oil Pump Corp. has high-efficiency, billet, bolt-in replacement oil pumps for the TC-88 and TC-88B engines that provides 40 percent more supply volume and 60 percent more scavenge volume than the stock H-D TC-88 oil pump. Large diameter gear rotors and tolerances create a high efficiency pump without the need for a high-friction spring washer. They have optimized their lifters, cam plate, and pushrods to work with the Feuling Oil Pump as a "Balanced System." The dyno-developed and track-tested combination of components will allow the Twin Cam engine to provide maximum power, reliability, and longevity.
The TC-88 and TC-88B engines have a small, die-cast, crank-speed gear, rotor-style oil pump that utilizes a spring washer to preload the pump gears against the cam support plate and pump housing. The side loading from the spring washer can cause excessive friction and premature wear.
The TC-88 engine uses a dry-sump lubrication system. To perform properly, the dry-sump system requires a properly sized balanced system, including a scavenge pump that is capable of removing all residual oil from the crankcase at all engine speeds and conditions. Failure of the scavenge pump to perform to these requirements causes "wet sumping." Instead of returning to the oil tank, the oil builds up in the crankcase and cam chest, causing excessive friction/power loss and oil aeration. This can result in oil being forced out the breather, air cleaner contamination, oil leaks, loss of oil supply, lifter clatter, component wear, and potential engine failure.
We wanted to install the Feuling parts and give them a run on the dyno to test them out for ourselves. We stopped by Horn Cycle Works in Pomona, CA, to snap a few photos of the install and make some runs on the dyno. For this article we plan to use a Harley-Davidson 103ci Screamin' Eagle Fat Boy; this bike has just over 7,600 miles, and is bone stock.