The Parts Bin – Valve Springs: Race, Street, and 60lb Springs – What’s the Difference

We’re back with another visit to The Parts Bin. This time, we’ve got our valve spring dyno set up so we can look at the differences between standard 60lb valve springs, conical street springs, and conical race springs. Read on to find out how these springs differ and which is right for your truck.

60lb Valve Springs – What to Know

First, we’re looking at standard 60lb valve springs. These are extremely common. They come stock on Cummins engines, and can be found anywhere. They are called a “barrel” spring due to their straight, symetrical shape. This means they are inexpensive and easy to find and work with.

The downsides of the 60lb springs is that they are the heaviest of the different spring types available. This means you are losing speed and accelaration within your valve train. Next, because each coil in the 60lb spring is the same diameter, they each move at the same resonance or frequency. If you watch high speed video of these springs, you can see the coils “bounce” with each movement. This means you are losing efficiency in your valve train.

Conical Valve Springs – What to Know

Conical valve springs have a cone shape to them, hence the name. This shape has a number of benefits. First, because the diameter of each coil gets smaller towards the top, there is less material in each spring. This means less weight in your valve train. On our scale, we weighed the conical springs at 71 grams, while the barrel spring is 92 grams. The shape also gives the greatest weight savings at the top of the spring, which improves efficiency since it has the farthest distance to travel. It goes farther, faster.

In a conical spring, each coil has a different diameter, they also have a different resonance. This reduces bounce in the coils. Essentially the vibration that would affect one coil will not affect the coils next to it because they are a different diameter. Additionally, the space between each coil is different, adding to this efficiency.

Race Conical Valve Spring – Press Test

First up, we have our conical race valve spring. This spring is rated at 175lbs on the seat at an install height of 1.87. We are simulating a 188/220 cam for this test.

Next, we move it to the intake level of the 188/220 cam, with is about .517 thousandths of lift. At this level, we’re looking at about 420lbs of force over the nose of the spring. Also, we are not at all near coil bind for this spring. We could have a more aggressive cam on this spring.

This is a lot of pressure on this spring, but it is a race spring, designed for high RPM, high pressure applications. This spring is going to put a lot of pressure on your cam lobes and the cam tunnels (blocks without bushings).

Street Conical Valve Springs – Press Test

The street conical is in the press. This valve spring has a little bit higher seat pressure than the race conical and is actually a longer spring. The street conical is rated at 175lbs on the seat at an install height of 1.95. We’re going to test this one the same as the previous, simulating a 188/220 cam.

At the intake level, we’re seeing 320lbs of force on this spring. That’s a full 100lbs less than the race spring. However, there is still plenty of room for a bigger cam before coil bind. It is nice to have a little lighter pressure over the nose. This will give your cam lobes and your cam tunnels a longer life.

60lb Springs – Just for Fun Press Test

Since we have the press set up, we decided to throw the 60lb valve springs on just to see how it compares. We are simulating the same setup with a 188/220 cam. We have this at an install height of 1.90 and are sitting around 160lbs of pressure.

At intake height, you can see this spring is sitting riht around 260lbs of pressure, but we are also near coil bind. If we try to bump it up to exhaust height, you can see the pressure level jump up, meaning we are coil bound.

Valve Spring Press Test Results

Hopefully these press test give you some insight into how different valve springs will perform in your truck and help you understand which you should choose for your diesel application. As always, if you have any questions, we are here to help. Feel free to ive us a call at 435-962-9555 or text us at 435-962-9506 or leave us a comment below. Don’t forget to follow us on YouTube, Facebook, and Instagram for more product tests. Leave us a comment below about what you’d like us to cover next.