Valve Spring Pressure Chart + Calculator

Choosing the right valve spring pressure is critical to valve control, rpm stability, camshaft life, and overall engine reliability. Too little spring pressure can lead to valve float and unstable valvetrain motion. Too much spring pressure can increase wear on the camshaft, lifters, guides, rockers, and other valvetrain components.

This page is designed to help you better understand seat pressure, open pressure, installed height, and how to estimate the right setup for your engine combination. If you want to calculate pressure based on your actual spring specs, use our Valve Spring Calculator.

Fastime Tip: A generic chart is a starting point, not a final answer. Always verify the spring requirements for your exact camshaft, intended rpm range, installed height, lift, and valvetrain combination.

Use the Fastime Valve Spring Calculator

Plug in your installed height, spring rate, and valve lift to estimate seat pressure and open pressure for your setup.

Open Valve Spring Calculator

What Valve Spring Pressure Do I Need?

The correct valve spring pressure depends on your complete combination. Camshaft design, net valve lift, rocker ratio, engine rpm, valve weight, retainer weight, and intended use all play a role. A mild street hydraulic roller combination usually needs much less pressure than a solid roller race engine that lives at high rpm.

The goal is to run enough spring pressure to maintain valve control without running more pressure than the combination needs. That balance is what helps protect parts while keeping the engine stable and efficient through the rpm range.

If you’re selecting springs for your build, check out our available valve springs here.

Valve Spring Pressure Chart

The chart below is a general reference for common performance engine combinations. Actual spring requirements can vary significantly based on lobe aggressiveness, engine speed, retainer and valve weight, and intended use.

Application	Typical Seat Pressure	Typical Open Pressure	General Notes
Mild Hydraulic Flat Tappet Street	90-120 lbs	220-300 lbs	Common on lower-lift street combinations
Performance Hydraulic Flat Tappet	110-140 lbs	280-340 lbs	Depends heavily on lobe design and rpm
Mild Hydraulic Roller Street	110-140 lbs	280-360 lbs	Common on many street performance builds
Performance Hydraulic Roller	140-180 lbs	350-450 lbs	Popular in more aggressive street/strip setups
Solid Flat Tappet	140-180 lbs	320-420 lbs	Always verify with the cam card
Mild Solid Roller	180-240 lbs	450-650 lbs	Varies substantially by lobe design and rpm
Aggressive Solid Roller Race	240+ lbs	650+ lbs	Race-only territory where exact specs matter

Important: These numbers are not a substitute for the cam manufacturer’s recommendation. Final setup should always include real installed height measurement, pressure verification, coil bind clearance, retainer-to-seal clearance, and full valvetrain compatibility checks.

Valve Spring Pressure Calculator

Spring pressure changes as the spring is compressed. That means actual seat and open pressure are directly affected by installed height, spring rate, valve lift, and any shim changes at the spring seat.

If you want a more accurate estimate based on your actual setup, use our Valve Spring Calculator. It is the fastest way to estimate how your pressure changes through lift.

Seat Pressure vs Open Pressure Explained

What Is Seat Pressure?

Seat pressure is the amount of force the spring applies when the valve is closed at installed height. This helps keep the valve seated and stable during the opening and closing events.

What Is Open Pressure?

Open pressure is the force applied by the spring when the valve is at maximum lift. This is critical for controlling the valve at higher rpm and preventing float or bounce.

Both numbers matter. A spring can have acceptable seat pressure but still be too weak at full lift if the spring rate is too low. On the other hand, a spring may show strong open pressure but still be too aggressive for the rest of the combination. That is why installed height, lift, and spring rate all need to work together.

For a deeper breakdown, see our upcoming guide on Seat Pressure vs Open Pressure Explained.

How to Measure Valve Spring Installed Height

Installed height is the distance from the spring seat to the underside of the retainer when the valve is fully closed and the locks are installed. This is one of the most important numbers in the entire setup because even a small installed height change can significantly affect spring pressure.

Basic Installed Height Steps

Install the valve in the guide.
Install the retainer and locks you plan to use.
Measure from the spring seat to the underside of the retainer using an installed height mic.
Compare that measurement to the spring manufacturer’s test height data.
Add shims as needed to reach the target installed height and pressure.

For a more complete walkthrough, see our guide on How to Measure Valve Spring Installed Height.

What Happens If Valve Spring Pressure Is Too Low?

Valve float at higher rpm
Valve bounce and unstable valve motion
Power loss
Erratic behavior under load
Possible piston-to-valve issues in severe combinations

What Happens If Valve Spring Pressure Is Too High?

Increased camshaft and lifter wear
More stress on pushrods, rockers, guides, and related valvetrain parts
Reduced component life
Unnecessary friction and heat
Potential reliability issues if the rest of the combination is not matched properly

Common Valve Spring Setup Checks

Before final assembly, verify more than just the advertised spring pressure.

Installed height verification
Actual seat pressure on the tester
Actual open pressure at net lift
Coil bind clearance
Retainer-to-seal or retainer-to-guide clearance
Spring seat and locator compatibility
Retainer, lock, and valve stem compatibility

LS Valve Spring Pressure Notes

LS combinations are especially sensitive to valvetrain stability because many builds use more aggressive hydraulic roller lobes, aftermarket rockers, trunnion upgrades, and higher rpm than stock. A spring that works on one LS setup may not be correct for another if lift, lobe design, rpm, or component weight changes.

On LS builds, always confirm:

Cam manufacturer spring requirements
Net valve lift with your rocker ratio
Installed height
Open pressure at actual lift
Retainer-to-seal clearance

Need Help Matching Valve Springs to Your Combination?

Fastime Performance can help you sort through spring pressure, installed height, lift, and valvetrain compatibility for your setup.

Start With the Calculator

Frequently Asked Questions

What valve spring pressure is too high?

That depends on the camshaft, valvetrain design, component weight, and intended rpm range. The issue is not a universal number, but whether the combination is running more pressure than it actually needs.

Can too much valve spring pressure damage an engine?

Yes. Excessive spring pressure can accelerate wear on the camshaft, lifters, pushrods, rockers, guides, and other valvetrain components.

Can too little spring pressure cause valve float?

Yes. Insufficient seat or open pressure can allow the valve to lose control at higher rpm, which can hurt power and damage parts.

How do I know my installed height is correct?

You need to physically measure it with the valve, locks, and retainer installed, then compare that measurement to the spring manufacturer’s specs.

Should I trust a generic valve spring pressure chart?

Use a chart as a reference only. Final spring selection should always be based on your actual parts and the cam manufacturer’s recommendation.