2007年12月9日星期日

Camshaft : A Go For Gold

Camshaft, in its simplest definition, are the lobes in an engine that operate the valves. It is driven by a crankshaft, either through a belt, gears or chains that run at one half the speed of its own. It also facilitates the opening and closing of these valves in all piston engines.

Getting a wrong camshaft is like wasting all your efforts on a dollar per dollar basis. Don't just be blinded by other engine management that of the electronic kind. No other single modification can come up with the same quality of function a camshaft can provide when it comes to cost-wise efficiency, power and driveability.

So, you're in for camshaft hunt? Here are some helpful tips you can take note of in getting a camshaft.

1. Camshaft for a resto or resto mod project

If you're going to get a cam for a resto or resto mod project, try to focus on its factory specs and do restoration by figures. Most camshaft company dealers will provide you with catalogs and amazing tech lines to help you pick the best camshaft.

Information regarding recommendations for the changes that will fit the camshaft like high stall torque converter, larger carburetor or exhaust headers, peak torque and a usable power hand and other related concerns should be answered and provided for by the company.

2. Camshaft for Vintage Engines

Take pride in upscaling the power and efficiency of your vintage engine, while camshafts let you take advantage of more modern grinds that creates more torque and horsepower by repetitive open and close motion of the values faster within the same specified duration.

Ideally, not all 280 degree camshafts behave and perform in the same manner. The camshaft's driveabililty and torque quality is directly related to the rate of opening and closing speed of the valve as well as its durability.

3. Limits and modification of camshafts

It is important to know the restored engines' practical limit and its special modification which a camshaft can accommodate. Engines with advertised duration are usually at 260 to 270 degrees.

So, how is a camshaft's duration measured? The method of measurement they use is at .050 inches of value lift. However, restored engines with 215 to 220 degrees camshaft duration don't really work well, and often times evaluated to have sluggish or laid back performance.

4. The camshaft centerline

While tip #3 teaches you so much about limits, modification and camshaft duration, do not forget and try to overlook its centerline, or what other people refer to as lobe separation angle.

Performance wise, it is one vital part that adds plus points to the camshaft's totality, to shape up a balanced combination of power and fuel efficiency. Standardized resto cams aim for 110 to 112 degree centerlines.

As for drag race cams, theirs is set on a 104 to 106 degree centerline, designed to produce a bit more on the mid-range torque, but would often times require a lot more other mods to begin with.

5. Camshaft Value Lift

As I've mentioned in tip #3, value lifts are the primary contributing factors to a camshaft's duration.

But although value lifts is one camshaft spec to go look after, it sets physical limit in things like value-to-piston clearance and value spring retainer-to-value guide clearance and value spring coil bind issues.

In this field, camshaft experts says it is always a go for the gold to target .450 to .475 inches of maximum value lift, especially for a modern v8s. For best results, ask assistance from your cam manufacturers to know details regarding physical measures of these things with critical dimension.

6.Camshaft Grind

Who says only singers could sing? Hey, camshafts can do it too!

When you're just about to come up with a cam grind, prepare to hear it sing. So how do you create a cam grind? By coating the cam from its bearing lobes and surfaces with quality assembly lube, you're bringing it a successful break in period!

To hail with all the electronic devices that are designed for engine management - because camshaft is and will still make most of the shots. The camshaft's timing specification is determined by the ideal parameters of peak horsepower, fuel mileage, peak torque, a usable power, magnifold vacuum.