Table of Contents
- 1 What is the stock rocker arm ratio on 454?
- 2 What is the stock rocker arm ratio for a big block Chevy?
- 3 How do I choose my rocker arm ratio?
- 4 How does rocker arm ratio affect lift?
- 5 How much lift does 1.7 Rockers add?
- 6 How much HP gain with roller rockers?
- 7 What’s the rocker arm ratio on a Chevy small block?
- 8 Are there roller tips for Vortec valve covers?
What is the stock rocker arm ratio on 454?
Registered. It is my understanding that while the stock BBC rocker arm ratio is 1.7, there is a standard deviation of about 0.1.
What is the stock rocker arm ratio for a big block Chevy?
The rocker arm ratio is the relationship between the 2 halves of the rocker arm. The halves are: The center of the valve stem to the center of the pivot point….How do I know what my rocker ratio is?
|Engine Type||Stock Rocker Arm Ratio|
|Gen. 5 Chevy LT Engines||1.8|
|Big Block Chevy||1.7|
|Small Block Ford||1.6|
What is the stock rocker arm ratio?
The rocker arm is the link between the camshaft and the valves – functioning as a lever arm to multiply the cams lobe lift to the valve lift. Stock rocker arm ratios vary between manufacturers and engine types, but generally all small block Fords come with a 1.6:1 ratio rocker arm.
What is the ideal leverage ratio for a rocker arm?
about 1.5:1 to 1.8:1
Current automotive design favors rocker arm ratios of about 1.5:1 to 1.8:1. However, in the past smaller positive ratios (the valve lift is greater than the cam lift) and even negative ratios (valve lift smaller than the cam lift) have been used.
How do I choose my rocker arm ratio?
The ratio of a rocker arm refers to the amount of movement on the valve side of the rocker arm in comparison to the pushrod side. A 1.5:1 rocker arm will move a valve 1.5 times the lift of the cam, assuming all things are in proper working order. If your cam has a lift of . 4 inches, multiply by 1.5 to get .
How does rocker arm ratio affect lift?
A higher ratio rocker arm also requires less lifter and pushrod travel to achieve the same amount of lift as a lower ratio rocker. A higher rocker ratio also reduces the amount of camshaft torque it takes to open the valves for a given amount of lift.
How much more lift does 1.6 Rockers add?
With a 1.6:1 rocker, this gives us 0.508-inch valve lift at max lift, an increase of 0.031 inch. It doesn’t sound like much, yet it was enough to show a sizeable gain, mainly because it increases the amount of time that the valves are open at higher lifts, allowing more air to flow through the heads.
How much does rocker ratio effect duration?
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.
How much lift does 1.7 Rockers add?
Without being too technical the 1.7’s will add . 30 to the lift of your cam…..so it should come out to .
How much HP gain with roller rockers?
With the baseline laid down, we moved on to a set of Comp Cams 1.5:1 roller rockers. At the same 6,000-rpm peak, we made 401.1 hp and 412.9 lb-ft of torque, a gain of 11.2 hp and 5.9 lb-ft of torque.
What does increasing rocker ratio do?
An increase in rocker arm ratio nets more than additional lift. It will also change the cam’s duration characteristics. Because the increased ratio effectively speeds up valve movement, that means the valve will reach any opening height sooner than it would with a lower-ratio rocker arm.
Do rocker arms increase horsepower?
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.
What’s the rocker arm ratio on a Chevy small block?
Even though Chevrolet made the decision easy for us when it engineered the small-block to run around a 1.5:1 ratio, (Comp Cams says most stock rockers are actually about 1.46:1), it’s well known that the inconsistencies of stock rockers and the friction and heat they create mean there’s power lost with them.
Are there roller tips for Vortec valve covers?
They should fit under the valve covers ok. The clearance problem is where the support stands for the bolts are, but the Comp roller tips are about the same size as the stock rockers, maybe even a little narrower. Powerhouse sell’s 1.6 ratio roller tip stock type Vortec for a decent price..
Which is better 1.6 rockers or 1.5?
Those results found the 1.6 rockers making more than 20 hp over the stock 1.5 rockers. But, that engine was equipped with a smaller cam than this one, and it seemed to really need the additional lift and duration afforded by the higher ratio.
How does the rocker arm work on a Chevy Camaro?
The full roller 1.5s did an excellent job of pumping even more horsepower, and the reduction in oil temp that comes along with the reduced friction these rockers offer make them an easy choice. The rocker arm mechanically multiplies the cam’s lobe lift. It does this by moving the pushrod closer to the fulcrum pivot point than the valve stem tip is.