Your car's engine wasn't made to last forever. Sooner or later, you're going to have to recondition your engine, especially its valve train parts. Most likely, after years of service, your valve spring shims are already worn–out. This will cause your valve springs to lose height–and soon after, you'll experience engine power loss. To restore and equalize your springs' height, you need to replace your old, useless stock shims. The Comp Cams Valve Spring Shim is a great choice. Unlike stock shims, which are easily damaged by the intense heat and pressure inside your engine, this product is made of premium–quality materials and is heated–treated to ensure high resistance against heat and pressure, so it's guaranteed that it won't easily wear out. To check your spring's installed height, you just need to install the spring cups and the spring shims and measure the distance of the valve's outside edge and the spring seat. Generally, an installed height of more or less 0.020 inch is acceptable. If the distance is more than that, you need the shims to decrease the space and to ensure that the spring's height is correct. You can use as many valve spring shims as you need to bring back the installed height of each valve spring to specs. It'll make sure valve spring tension is just right for smooth valve performance. Remember, when fitting in new valve springs, you have to make sure each has the right installed height and tension. Get the Comp Cams Valve Spring Shim set from Auto Parts Warehouse now!