Do you want to learn how to increase your engine’s performance and power output? Calculating cam lift with 1.7 rockers is a great way to do just that.
By understanding the importance of cam lift and rocker arm ratios, you can easily calculate your cam lift and take advantage of its improved engine performance potential.
Read on to learn more
How To Calculate Cam Lift With 1.7 Rockers?
To calculate cam lift with 1.7 rockers, multiply the advertised lift by the rocker ratio (1.7).
For example, a cam with an advertised lift of 0.500″ would have a lift of 0.850″ (0.500″ x 1.7) at the valve with 1.7 rockers installed.
Why Use 1.7 Rockers?
One of the most significant benefits of using 1.7 ratio rocker arms is the increased lift and duration without changing the camshaft.
This means you can retain the same camshaft, which saves money and time.
Additionally, increased lift and duration improve airflow and power output, making it a popular upgrade for hot-rodders and racers.
How to Calculate Cam Lift with 1.7 Rockers
Calculating cam lift with 1.7 rockers is relatively simple. You’ll need to know the camshaft’s advertised lift and the rocker arm ratio. Follow these steps:
Determine the Advertised Cam Lift
The advertised cam lift is the lift specified by the camshaft manufacturer.
It’s typically measured at the camshaft lobe and doesn’t account for any valvetrain losses or rocker arm ratios.
You can find this information on the camshaft manufacturer’s website or in the product literature.
Calculate the Gross Lift
To calculate the gross lift, multiply the advertised cam lift by the rocker arm ratio.
For example, if the advertised lift is 0.500″, the gross lift with 1.7 rockers is 0.850″ (0.500″ x 1.7).
Account for Valvetrain Losses
Valvetrain losses occur due to the flexing and bending of the pushrods, lifters, and valve springs.
The amount of loss varies depending on the valvetrain components and engine RPM.
As a general rule of thumb, you can assume 10% losses for hydraulic lifters and 15% losses for solid lifters.
Calculate the Net Lift
To calculate the net lift, subtract the valvetrain losses from the gross lift.
For example, if the gross lift is 0.850″ and the valvetrain losses are 10%, the net lift is 0.765″ (0.850″ – (0.850″ x 0.10)).
How To Use A Camshaft Card To Determine Cam Lift With 1.7 Rockers?
Here we will discuss how to use a camshaft card to determine cam lift with 1.7 rockers.
Gather the Necessary Tools
Before beginning, gather the necessary tools, including a camshaft card, a dial indicator, and a degree wheel.
You will also need a set of 1.7 ratio rocker arms and a rocker arm stud with the same thread pitch as your engine.
Install the Camshaft
Install the camshaft into the engine according to the manufacturer’s instructions.
Ensure that the camshaft is correctly aligned with the timing marks on the timing chain.
Install the Rocker Arms
Install the 1.7 ratio rocker arms onto the rocker arm studs. Tighten the nuts on the rocker arms to the manufacturer’s specifications.
Set Up the Dial Indicator
Mount the dial indicator onto a stable surface, such as the engine block or cylinder head. Position the indicator’s contact point on the top of the valve stem.
Rotate the Engine
Rotate the engine in the direction of rotation until the intake valve on the cylinder you are measuring begins to open.
Continue rotating the engine until the valve reaches its maximum lift.
Record the Valve Lift
Record the valve lift from the dial indicator. Repeat this process for the exhaust valve on the same cylinder.
Calculate the Cam Lift
To calculate the cam lift, multiply the recorded valve lift by the rocker arm ratio (1.7 in this case).
For example, if the recorded valve lift is 0.500 inches, the cam lift is 0.850 inches (0.500 x 1.7).
Check the Camshaft Card
Compare the calculated cam lift with the lift specification listed on the camshaft card.
If the calculated cam lift is within the range specified on the card, the camshaft is correctly installed.
Why calculating cam lift with 1.7 rockers is important for engine performance?
Using 1.7 rockers can significantly impact cam lift, and here’s why it matters.
Increased Valve Lift
Using 1.7 rockers can effectively increase valve lift, which translates to more air and fuel entering the combustion chamber.
This leads to improved engine performance, as it enhances the engine’s breathing capabilities and allows for more power output.
Additionally, the increased valve lift can result in improved fuel efficiency, as the engine can operate more efficiently with better air and fuel intake.
Improved Exhaust Flow
Another benefit of calculating cam lift with 1.7 rockers is the improved exhaust flow.
The increased valve lift allows for more exhaust gases to exit the combustion chamber, which can enhance engine efficiency and performance.
Improved exhaust flow can also help reduce engine temperature, prolonging the engine’s lifespan and preventing overheating.
Optimal Engine Timing
Calculating cam lift with 1.7 rockers can also lead to optimal engine timing, which is crucial for maximizing engine performance.
Optimal timing ensures that the valves open and close at the right moments, allowing for efficient air and fuel intake and exhaust.
This can result in improved engine power, torque, and overall performance.
Reduced Engine Stress
Using 1.7 rockers to calculate cam lift can also help reduce engine stress, as it allows the engine to operate at a lower RPM while still achieving optimal performance.
This can result in a longer engine lifespan and reduced maintenance costs, as the engine is less likely to experience wear and tear.
FAQ
What Is Cam Lift And How Is It Measured?
Cam lift is the vertical displacement of the camshaft lobe, which determines the lift of the valve.
It is measured by using a dial indicator to measure the distance between the base circle of the camshaft and the highest point of the cam lobe.
How Does The Rocker Arm Ratio Affect Cam Lift?
The rocker arm ratio affects cam lift by multiplying the lift generated by the cam lobe.
For example, a 1.5 rocker arm ratio will multiply the cam lift by 1.5, resulting in a higher valve lift.
Similarly, a 1.7 rocker arm ratio will multiply the cam lift by 1.7.
What Is The Formula For Calculating Cam Lift With A 1.7 Rocker Arm Ratio?
To calculate cam lift with a 1.7 rocker arm ratio, you can use the formula: Cam lift x 1.7 = Valve lift.
So if the cam lift is 0.5 inches, the valve lift would be 0.5 x 1.7 = 0.85 inches.
Can A 1.7 Rocker Arm Ratio Be Used With Any Camshaft?
Not necessarily. The suitability of a 1.7 rocker arm ratio depends on the specific camshaft profile and engine setup.
It is best to consult with a knowledgeable engine builder or camshaft manufacturer to determine the optimal rocker arm ratio for your specific application.
What Are Some Advantages Of Using A Higher Rocker Arm Ratio?
Using a higher rocker arm ratio can result in increased valve lift, which can improve engine performance and power output.
It can also help compensate for other engine modifications, such as increased cylinder head flow, that may require more valve lift to take advantage of the improved airflow.
Are There Any Downsides To Using A Higher Rocker Arm Ratio?
Using a higher rocker arm ratio can put additional stress on the valve train components, particularly the valve springs.
It can also increase the likelihood of valve float at high RPMs, which can cause engine damage.
It is important to ensure that the valve train components are properly matched and that the engine is tuned to operate safely with the higher rocker arm ratio.
How Do I Know If A Higher Rocker Arm Ratio Is Right For My Engine?
Determining the optimal rocker arm ratio for your engine depends on several factors, including the camshaft profile, cylinder head flow, and intended use of the engine.
Consulting with a knowledgeable engine builder or camshaft manufacturer can help you determine the best rocker arm ratio for your specific application.
It is also important to ensure that the rest of the engine components, including the valve train, are properly matched to handle the increased lift generated by the higher rocker arm ratio.
Conclusion
Calculating cam lift with 1.7 rockers may seem like a daunting task, but it’s actually a simple formula that can be easily mastered.
By knowing the basic measurements of your engine, and understanding the relationship between your camshaft and rocker arms, you can accurately calculate your cam lift and optimize your engine’s performance.
So whether you’re a seasoned mechanic or a DIY enthusiast, take the time to learn how to calculate cam lift with 1.7 rockers, and watch as your engine roars to life with newfound power and efficiency.
