SKU:

1-1001 HI ROLLER Camshaft for Evolution "Big-Twin"

HYDRAULIC PERFORMANCE CAM 1984-Up Harley-Davidson

With our multi-index cam gears you have the versatility of three cam timing settings with one camshaft. One position gives 4? advance to original cam timing and another position is 4? retarded to the original timing. Overall, an 8? timing range is available with the HI-Roller Crane camshafts for your ?Big Twin??.
What does a change of cam timing do? An advance in cam timing will lower the ?power band? of the engine, while retarding the cam will raise the ?power band?. Of course the amount of change will vary depending on other engine components. Generally we?re talking about a two or three hundred RPM. power band change each way.

Hydraulic Performance Cam Mid range and upper RPM improvement. Works best with 10:1 compression ratio and performance carb and exhaust. Excellent for modified touring bikes. May require valve spring change. Check all clearances.

Part Number: 1-1001

Grind Number Hi-Roller 296-2 Duration @ .053" Open/Close, Int-Exh 252?/262?, 23/49 - 56/26 Gross Valve Lift (@TDC), 1.6:1 Rkr Ratio Int/Exh .490"/.500", (.198"/.206") RPM Range 2,500 - 6,000

1. Riding Style
Is the bike for weekend use or your main form of transportation? Is the bike being used for short trips around town “from light to light”, or for touring long distances? What terrain do you ride? Is high performance or racing your primary concern?

2. Weight Of The Bike
What does it weigh? Is it light, or weighted down with accessories? Do you tow a trailer or have a side-car? Do you ride solo or tandem?

3. Operating RPM Range
What gearing does the bike have? How many speeds to the transmission? Does the bike have “International” gearing? What rpm range are you most likely to be operating in?

4. Engine Displacement And Compression Ratio
What cubic inch is your engine and what compression ratio does it have?

5. Engine Modifications And Engine Accessories
To obtain the maximum potential from your bike it is important to have engine components that are compatible. The components, accessories and modifications to consider are:

a. Air Cleaner / Filter / Jetting
b. Exhaust System
c. Ignition System
d. Carb Size, Style, or F.I.
e. Compression Ratio
f. Cyl. Head Modifications
      1. Perf. Valve Springs
      2. Enlarged Valve Diameters
      3. Porting, Polishing, Milling
g. Aftermarket Cyl. Heads
h. Nitrous Oxide
i. Supercharger or Turbo

The Heart Of The Matter

An engine is a giant air pump and the more efficiently the air moves through it the more power the engine makes. The camshaft opens and closes the valves allowing the air to enter and exit. Camshafts differ in design, but the two main factors are the amount of “duration” and “valve lift”. The “duration” is the time the valve is open (measured in degrees of crankshaft rotation).

Duration determines the “rpm potential” of the engine and power band. The longer the duration period the higher the RPM the powerband will operate at. The “lift” is the distance the valve opens (it is measured in thousandths of an inch of travel). The more lift the more air/fuel mixture can enter and exit the engine, thereby producing more torque.

Bigger’s Not Always Better

The camshaft provides an “rpm power band” that is approximately 3,000 rpm wide. This rpm power band can be produced in either the Lower Range (from off idle to 3,500 rpm), in the Mid Range (from 2,000 to 5,000 rpm) or in the High Range (3,500 to 6,500 rpm). Select the camshaft that will perform the best in the particular rpm band that the bike will be operating in.

The amount of valve lift that the engine can accept is often determined by valve to piston clearance, valve to valve clearance, and the amount of travel the valve spring can handle before its coils touch one another and bind up. Big lift camshafts could require modified cylinder heads or pistons and performance valve springs with additional travel.

Power vs Weight

The “horsepower to weight ratio” is very important. You must produce the right amount of power at the correct rpm range. A heavy bike normally needs a cam that will provide good lower rpm power (torque) to get the bike moving. Generally, a cam with less duration would work the best in a heavy bike. A lighter bike requires less low end power, therefore a cam that provides power in the higher rpm range would be better suited.

But of course there are always the exceptions. A rider with a heavy Dresser who rides the open highway might not care how long it takes for the bike to wind-up to speed. He likes to ride at 65 mph and wants to pass up to 90 mph! In this case, a cam with increased duration and rpm potential would work best.

Balancing Compression

Generally speaking, the greater the amount of “cylinder pressure” the more power the engine will have. This is determined by the engine’s compression ratio and the amount of duration the camshaft has. Cylinder pressure goes up with either an increase of compression ratio or a decrease in camshaft duration.

Cylinder pressure goes down with either the increase of camshaft duration or the decrease of compression ratio. An excessive increase in the camshaft duration could lower the cylinder pressure causing a loss of performance. In order to counteract this effect the compression ratio of the engine would need to be increased (by milling the heads or changing the pistons) to gain back the loss in cylinder pressure.

Stock compression ratio for early Panhead® and Shovelhead® engines was 7.0:-1 to 7.5:1. Later model Evolution® engines are around 8.5:1. Modified engines for street use can have 9.0:-1 up to 10.5:1 compression ratio depending on the circumstances. Racing applications use 11.0:1 and higher compression. Because the quality of the “pump gasoline” is decreasing, engines above 9.5:1 might need octane booster additives to avoid detonation and pinging.

Note: It is important to mention here that cylinder pressure is also affected by altitude. The higher the altitude the less atmospheric pressure. This makes it more difficult for the engine to produce power. At high altitude (above 3,500 ft.) with a stock compression ratio engine, a camshaft with less duration is recommended. If a longer duration cam is selected you must raise compression.

When Bigger Is Better

Larger cubic inch engines work better with cams with increased duration and lift. The increase in cubic inches demands an increase of airflow. In this case the longer duration cam would be recommended. (The engine will also work better with a larger carburetor, high-flow exhaust, and cylinder head improvements.)

Unlike the stock cubic inch engine that needs an increase of compression ratio with a larger duration camshaft, a large cubic inch engine will absorb the larger design cam without necessarily requiring an increase in compression. The larger cubic inch engine will also cause the larger duration camshaft to build max power at a lower rpm than is described in the catalog.

A Perfect Match

It is important to choose component parts that will work together and enhance performance. If the bike is going to remain stock with only minor changes, a mild duration cam with a free flowing air cleaner, filter and a jetting kit is all that may be necessary. At the other extreme, with aftermarket heads, a big carburetor and large diameter exhaust pipes, a longer duration cam with big lift would be required. Superchargers, turbos or nitrous oxide systems require special consideration a custom designed cam. Be sure that the accessories you purchase are compatible with one another to obtain the goals you desire.

Which Crane Cam Is Right For My Bike?

Crane FireBall® Camshafts
Crane FireBall® Cams are computer designed to give reliability and power. They are manufactured to the industry’s highest quality standards and are available in a variety of profiles for both street and performance applications for Evolution®, Shovelhead® and Panhead® engines. Most FireBall® grinds can be used with stock valve springs and do not require removal of the cylinder heads for machining. FireBall® Cams are also competitively priced and backed by a 1 year limited warranty.

Crane Hi-Roller Cams
Crane Hi-Roller Cams are computer designed for bikes with more performance engine modifications. Hi-Roller Cams are specially designed to take full advantage of performance modifications.

Hi-Roller cams come with our unique Multi-Index Cam Gear. This gear features three separate keyway positions which allows the cam to be advanced or retarded by 4 degrees. The cam gear can be removed and repositioned. If moved to the “advanced” keyway the power range will come on approximately 300 rpm sooner, building better bottom end power. If the gear is repositioned to the “retarded” keyway, the power range moves up approximately 300 rpm higher, for better top end power.

Some Hi-Roller Cams require removal of the heads to install performance valve springs and to be checked for and to provide proper retainer to guide, piston to valve, and valve to valve clearances. All Hi-Roller Cams are made to the industry’s highest standards and backed by a one year limited warranty.