Have you ever installed a bigger cam only to find the engine makes less power at a lower rpm? If you’ve been on a chassis or engine dyno you’ve surely seen the phenomenon displayed on the print out. The engine is pulling hard then seems to hit a wall and power drops off a cliff. Most veterans know this as a tell tale sign of valve float. “Spring is in the air”, some say, in reference to the fact you probably didn’t upgrade to proper springs when you threw in that higher-lift cam.

The reason this is so common of a problem is that most recreational enthusiasts often don’t know to check this sort of stuff, and even when they do they forgo it because they don’t have the proper tools. Valve spring pressure testers were usually only found in good performance machine and cylinder head shops. Well not anymore. ProForm’s mini spring tester (PN: 66834) works in a bench vice or drill press. Simply clamp it in place, position your spring against the pad and clamp down to the desired height. The large dial indicator reveals pressure in 10lb. increments up to 600lbs. per inch.

It is best practice to always check the cam card for spring pressure requirements. The cam companies always indicate what spring pressure you need at installed height (height when valve is closed) and open height (height when valve is open to maximum lift.) Use a machinists rule or dial indicator mounted to your vice or press to clamp the spring down to these two heights and then take a pressure reading. If the spring does not have the required pressure (+/- 10%) you should get new springs. Test several or all of the springs on each head, and if they are within 10% you can usually get the pressure close with some shim placement under spring. (Always check for bind between the coils and valve guide clearance when shimming springs.)

This tool is rugged enough to be taken to races or lent to friends (though at $70 they should get their own if they are serious about performance.) It has a calibration reset feature as well.

For more information on the Mini Spring Tester, including where to buy it, visit: Proform’s website.