## What is Cam duration and lift?

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.

Advertised Duration is the degrees of crankshaft rotation that the lifter is raised more than a predetermined amount..

## How much lift does 1.7 Rockers add?

According to This Article from Hot Rod magazine, a . 1 increase in rocker arm ratio (such as 1.6 to 1.7) will increase lift by about . 030, which would put me right back at the . 542 lift of the X-303, while maintaining the extra duration of the F-303.

## Are roller rockers noisy?

Hard to tell what your definition of loud is, but yes roller rockers do make noise. Just make sure you have done the normal adjustment to the valve train and your good.

## What is the difference between 1.6 and 1.7 roller rockers?

1.6 ratio is the stock ratio, 1.7 gives you more lift, around . 300 more lift which will give you 10 – 30 more HP depending on your setup. both clear stock valve covers, but you may or may not have to pound out the baffles in the stock covers.

## How is maximum valve lift measured?

Tip: To quickly find maximum lobe lift, measure the base circle of the cam and subtract it from the thickness across the cam lobe’s highest point (see the diagram below). Tip: Maximum valve lift can be calculated by multiplying the maximum lobe lift times the rocker ratio.

## How much duration does 1.6 Rockers add?

As rocker ratio is increased, so, too, is valve timing. Note how changing from the stock ratio, which is actually closer to 1.46:1, to a true 1.60:1 will increase your total valve duration by almost 20 degrees! This geometric increase is true for any cam in any engine.

## What is rocker ratio?

Rocker Ratio. Rocker Arm Ratio is the length of the valve side of the rocker arm to the center (or pivot point) of the rocker arm divided by the length of the Cam or Pushrod side to the center of the rocker arm.

## How do you calculate lift on 1.6 rockers?

To determine the change in lift when changing rocker arm ratios, divide the lift of the cam by the original rocker ratio (which gives you the lobe lift), then multiply this number by the new rocker ratio. For example, a popular small block chevy cam has . 468 lift at the valve.

## Are 1.6 rockers worth it?

Not worth it IMO if you already have 1.5 roller rockers or roller tips. It would be worth more if you had stock rockers right now since the ratio of stock rockers can be much lower then the advertised 1.5:1.

## What is the difference between 1.5 and 1.6 roller rockers?

1.5 rockers lift the valve 1.5 times the lobe lift of the cam, 1.6 lift the valve 1.6 times lobe lift. Generally, 1.6 rockers are used to improve the lift of a camshaft that has low lift. They can also be used to get the valve lift into a specific head flow range.

## How much horsepower will a roller cam add?

I saw a few tests over the years and most of them with the same lift and similar duration adds ~50 HP and the most I believe was ~75. The benefit from a roller is the extra capacity, so if you just slap the same specs cam in there, you would NOT get your money’s worth.

## What are the advantages of roller rockers?

A more obvious benefit of installing roller rockers is that of reduced friction and wear. The stock rockers slide over the end of the valve stem putting a considerable amount of side pressure on the stem. This creates friction and wears the stem and guide.

## Can you put roller rockers on a flat tappet cam?

Roller camshafts and lifters can be used in an engine that features nonroller rockers; by the same token, roller rocker arms can be used in an engine that features a flat-tappet solid or hydraulic camshaft.

## How much HP do roller rockers add?

For engine applications that demand a step up, replacing the stock stamped or cast steel rockers with aluminum roller rockers will typically produce a gain of 10 to 15 hp with the same lift ratio, and even more of a power gain with a higher lift ratio.

## Are roller rockers worth the money?

roller rockers are always worth the money and effort imo. you get less friction, and a more consistent rocker arm ratio. and while you most likely will not feel the difference seat of the pants, the engine will like it with about a 5hp gain overall.

## Do lifters increase HP?

All the motion in the valvetrain starts and ends with the camshaft. In pushrod engines, the rotation of the cam lobes under the lifters actuates the valvetrain. … Flat tappet cams are the worst, so upgrading to a roller cam and lifters can significantly reduce friction while increasing usable horsepower at the flywheel.

## How do you check pushrod length?

If the pushrod is too short, the mark will be toward the intake (inboard) side of the valve tip. If the pushrod is too long, the travel will be toward the outboard or exhaust side of the valve tip. An ideal pushrod length will minimize the travel across the center of the valve tip.