Hyd Roller vs Hyd Flat tappet on SM heads
And thanks to Early A for his excellent drawing in post #71. This drawing shows another 'anomaly' with rockers that affects the final valve movement [ lift ]. I didn't mention it earlier because it would have complicated things. This is one reason why the overall ratio can vary so much as shown in post #61.
Looking at post #71, look at the max lift, & look at the vertical line drawn from the roller pivot to the valve tip. The distance from that contact point on the valve tip to the fulcrum pivot represents the 'lever length' on the valve side of the rocker. Notice that this distance is longer than the distance from the fulcrum pivot to the roller pivot. The diam of the roller will have an affect. You have similar variances on the prod side of the rocker. All adds up to the discrepancies that show actual measured ratio v advertised ratio.
And thanks to Early A for his excellent drawing in post #71. This drawing shows another 'anomaly' with rockers that affects the final valve movement [ lift ]. I didn't mention it earlier because it would have complicated things. This is one reason why the overall ratio can vary so much as shown in post #61.
Looking at post #71, look at the max lift, & look at the vertical line drawn from the roller pivot to the valve tip. The distance from that contact point on the valve tip to the fulcrum pivot represents the 'lever length' on the valve side of the rocker. Notice that this distance is longer than the distance from the fulcrum pivot to the roller pivot. The diam of the roller will have an affect. You have similar variances on the prod side of the rocker. All adds up to the discrepancies that show actual measured ratio v advertised ratio.