Regular watchers of Redline Update know that Davin can sometimes bounce from topic to topic, but today he has sprung onto one that involves, well, a decent amount of tension. We’re talking, of course, about valve springs. One of the most critical components inside an internal combustion engine are the valves and their configuration. Get it wrong and your engine will not last long—if it runs at all. Luckily, Davin is all about getting it right. On this week’s episode, he shows us what’s essential for you to do the same.
Valve springs are a key piece of a larger engine puzzle. Their function is to keep the valves closed at the proper moment, allowing for efficient combustion, and also to keep the lifter in contact with the camshaft. What kind of lifter you are using is crucial for to making sure you have appropriate springs. A flat-tappet lifter is exactly what it sounds like: a lifter that rides on the camshaft, with a flat bottom on it. That bottom is hardened and the egg-shaped profile of the cam pushes on that hardened end to push the valve open. Simple!
A common upgrade is the roller lifter, replacing that flat bottom with a smooth roller wheel that rides on the cam. This design removes friction from the system and allows for a more aggressive profile on the camshaft. That profile can achieve more lift, and do so faster, which lets more air and fuel flow in and out of the combustion chamber. Roller lifters require more spring pressure to keep the lifter in contact with the cam.
To set the exact spring pressures, Davin uses a handy tool to measure how much force the spring exerts when compressed a to specific degree. From there he can add shims between the spring and the cylinder head to raise the clamping pressure to meet what Delta Camshaft recommends for the custom cam that he is installing. It’s a straightforward but still time-consuming process that ultimately will take our engine to the next level. To learn other tips and tricks be sure to subscribe to the Hagerty YouTube channel to never miss a Redline Update or the full time-lapse Redline Rebuild episodes.
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