# How do you calculate overlap on a camshaft?

## How do you calculate overlap on a camshaft?

How is it measured? Overlap can be calculated by adding the exhaust closing and the intake opening points. For example, a cam with an exhaust closing at 4 degrees ATDC and an intake opening of 8 degrees BTDC has 12 degrees of overlap.

### How much should a camshaft overlap?

To maintain sufficient idle and vacuum qualities, the cam tech recommends the cam be ground on, say, 112-degree LCA, which gives an overlap of 66 degrees. For a typical performance-headed 350, the optimal LCA is usually 108 degrees.

How is overlap calculated?

Exhaust Closing Point + Intake Opening Point = Overlap In this example, there will be overlap.

What does overlap mean on a camshaft?

A: Overlap is when the intake and exhaust valves are open at the same time. It is expressed in degrees of crankshaft rotation. Not all camshafts have overlap. If they do, it happens at the end of the exhaust stroke and the beginning of the intake stroke.

## What is considered a big camshaft?

When someone refers to a “big cam,” they mean it has longer duration, not higher Lift. Manufacturers often list 2 different duration values: Advertised Duration is the degrees of crankshaft rotation that the lifter is raised more than a predetermined amount. This predetermined amount varies between manufacturers.

### How much cam lift is too much?

If the port is getting turbulent above . 600″ lift, lifting the valve above . 600″ can actually hurt the power. It seems that for every degree you spend above where the port goes turbulent, it takes 2 degrees to recover from it.

What is overlap data?

When the columns of a table are formed from the categories of a multiple response variable, data from the same case can be present in both of the columns being tested. This is known as overlapping data, and it means that the two samples cannot be considered independent.

What is the advantage of having a larger overlap period?

Valve overlap is designed into the engine and is most useful at higher speeds. At higher speeds, the extra amount of intake charge brought into the combustion chamber provides a substantial increase in available power. The amount of time that both valves are open in directly related to engine rpm.

## What is the difference between a Stage 1 and Stage 2 camshaft?

Most Stage 1 type modifications are typically in the +10-15% power increase over stock. Stage 2: this is typically referred to an engine with a performance cam upgrade as well as the other components within a Stage 1 combination. A typical Stage 2 has generally +20-25% more HP than stock.