Jim Smart
December 25, 2006
Contributers: Marvin Mcafee Photos By: Marvin Mcafee

Install A Windage Tray
Windage trays keep oil away from the crankshaft at high revs. As the crank spins faster, it tends to draw oil out of the sump into the spinning crankshaft. Windage trays, such as those from MPG Head Service, prevent oil windage, which reduces internal drag. Knife-edging crankshaft counterweights also reduce crankshaft aero-drag. Oil and air drag rob power. Less drag-more power.

Install A Flex Fan or Thermostatic Clutch Fan
For years, we have debated the merits of different kinds of radiator cooling fans. Ideally, you will have a fan that does it all-cools effectively while borrowing as little engine power as possible. A traditional Flex-a-lite 17-inch aluminum six-blade flex fan moves a whole bunch of air across the radiator under normal operating conditions. At high revs, flexible blades flatten out, which reduces drag and keeps airflow consistent. Remember, above 35 mph road speed, your engine doesn't even need a cooling fan, as ram air through the radiator is sufficient.

Thermostatic clutch fans, such as those from Flex-a-lite, work even better than flex fans because they engage the water-pump drive only when needed. A clutch-fan freewheels on the shaft when it isn't needed. This frees up power. As the radiator warms, the fan clutch engages with some slippage, pulling cool air through the radiator. Any way you slice or dice the time-proven clutch fan, it does a wonderful job, answering the call only as needed. Use a plastic-blade clutch fan and grab even more power. Clutch fans are also quieter.

Install A Crankshaft Wiper At The Pan Rail
Crankshaft wipers, like windage trays, keep oil where it belongs. Use a crank wiper to free up power, too.

Use Low-Tension Piston Rings
Low-tension piston rings from manufacturers such as Federal-Mogul/Speed-Pro reduce friction and free up power. The downside is shorter service life, accompanied by increased blow-by. Excessive blow-by can hurt power, which is the other side of the coin. Getting power is all about compromise. You can't have it all.

Roller Timing Set
Roller timing sets are little more than a true dual-chain drive, which reduces friction. Roller timing sets reduce internal friction just like roller rockers and roller tappets do. Instead of tight, hard-over friction like you would experience pushing a wagon across rough concrete without wheels, roller technology puts wheels under the Radio Flyer, making the wagon easier to push.

Full Roller Rockers
The savvy engine builder thinks of every possible place power can be lost during an engine build. Whenever you examine internal friction issues, there are countless areas where power will be robbed. Bearing clearances, piston-ring tension, timing-set tension, and so on can make a big difference in power. Factory stamped-steel or iron rocker arms experience friction at the fulcrum, pushrod pocket, and valve-stem tip. This may not seem like much until you multiply these friction points 16 times over. It adds up to a lot of power loss (around 15 percent) due to friction. Full roller rocker arms, meaning roller tip and roller fulcrum, reduce friction dramatically. Think about it this way-less friction means more power. Full roller rocker arms can net up to a 15-percent increase in power.