What gives a cam a choppy idle?

Overlap causes misfires at idle and that makes the lope or choppy idle. It causes a lot of intake reversion which causes the engine to basically choke on it's own exhaust during idle.

Also to know is, what causes a cam to lope?

Lope is a result of the intake and exhaust valves both being open at the same time. This is called overlap. Mild cams have little or no overlap at any valve opening that makes a difference. Hotter aftermarket type cams have a lot because it aids high RPM breathing.

Beside above, does a cam change the sound? cam controls the valve action and timing. better cylinder filling = more compression, bigger BOOM sound. engine is louder. simply put.

Also to know, what makes a cam sound lumpy?

The overlap of the exhaust valve closing and intake valve opening causes the engine to be inefficient at low speed which results in the lumpy idle. The closer the Lobe Seperation Angle the more the overlap, the more duration the more (typically) the overlap.

What does duration on a cam mean?

Duration is how long the valve is off its seat. It is listed in degrees of crankshaft rotation. When someone refers to a "big cam," they mean it has longer duration, not higher Lift.

What causes loping idle?

A rough idling engine can be caused by spark plugs or spark plug wires. A plug that is damaged or installed incorrectly can result in fuel being burned at an inconsistent rate. If the damage is bad enough, you may also notice your engine running rough while driving.

What is Lope idle?

What is it about high-duration cams that causes engines to lope at idle? the lope comes from what is effectively(in engine combustion terms) an overlap between one cylinder opening and another closing.

Is valve overlap bad?

Most recent answer. A reasonable positive vale overlap helps to clean combustion residuals in engine cylinder, too much valve overlap would help to expel the fresh charges into exhaust pipe thus increase HC and CO emission and hence results in bad fuel economy.

How does lobe separation affect idle?

In conclusion, lobe separation angles change the amount of valve overlap, which affects many performance factors particularly idle quality, peak torque that can be moved from a lower rev range to a higher range and power bands that can be narrowed or broadened.

What is Cam grind number?

The grind number gives you the basic cam info. Like the Crane 274HO6-tells you the adv. duration is 274 degrees, H is for hydraulic, an 06 tells you the lobe separation angle of 106. Part number is 100172 which really tells you nothing.

What does a camshaft look like?

Uses. In internal combustion engines with pistons, the camshaft is used to operate poppet valves. It consists of a cylindrical rod running the length of the cylinder bank with a number of oblong lobes protruding from it, one for each valve.

What is CAM in a car?

Image courtesy of ClearMechanic.com. The camshaft is a rotating shaft (or shafts) in an engine that activates the intake and exhaust valves for each cylinder. As the shaft turns, cams along its length press down on the spring-loaded valves in synchronicity with the motion of the pistons and firing of the spark plugs.

What does cammed out mean?

Cam out (also cam-out or camming out) is a process by which a screwdriver slips out of the head of a screw being driven once the torque required to turn the screw exceeds a certain amount. Repeatedly camming out damages the screw, and possibly also the screwdriver, and should normally be avoided.

What do roller rockers do?

A roller rocker is a rocker arm that uses bearings instead of metal sliding on metal. It has a wheel on its end like that of a measuring wheel, which rolls by the use of needle bearings. For pushrod engines, roller rockers employ a roller where the rocker contacts the valve stem.

What is CAM?

Computer Aided Manufacturing (CAM) is the use of software and computer-controlled machinery to automate a manufacturing process. Based on that definition, you need three components for a CAM system to function: Software that tells a machine how to make a product by generating toolpaths.