Originally Posted by hondar
1. change to the valvesprings that were proven not to coil bind at the cam's max. lift on a Spintron test but not go overly stiff to create excessively high valve seat pressures (stock 40 lb., Toda valvesprings 50 lb., max. acceptable range is 70-90 lb. at 33.66 mm installed valvespring height) causing wear.
if you don't upgrade the valvesprings, even though the company says it's ok to use the stock ones, you still will see mild valve float. Mild valve float is not catastrophic compared to severe valve float or coil binding.
But you know what valve float is right?
The spring has fatigued at high rpm and loses it's ability to control the rate at which the valve closes against the seat. The valveface slams shut against the seat and transfers this shock or load up the valve stem to the rocker arm and then to the camshaft lobe-rocker arm interface. You get extra wear-related damage and possibly structural fatigue at the valve seat, valveface, rocker arm lobe, valvespring retainer, and cam lobe. Valve float can be identified on a chassis dynosheet as a sudden very sharp or steep drop in hp (in the order of 5% [7-10 whp] or more) at the last 500-600 rpm before the redline.
hondar