Pushrod Q:
10-12-2011, 02:44 AM
#21
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The spring pressures are based on the spring's rate (lbs/inch) and the spring deflections.
The closed pressure is dependent on the spring's installed height, and the open pressure is dependent on the max valve lift (ie, max spring compression).
Coil bind has really nothing to do with the seat pressures, but strickly on the max expected deflection. At the max valve lift, there should be at least 0.060" clearance between the remaining open coils - and this should definitely be checked on the car.
Choosing the right springs is mostly dependent on the max expected valve lift to ensure there is no coil bind, and that the springs are stiff enough to prevent valve float with the cam profile at max expected RPM.
The closed pressure is dependent on the spring's installed height, and the open pressure is dependent on the max valve lift (ie, max spring compression).
Coil bind has really nothing to do with the seat pressures, but strickly on the max expected deflection. At the max valve lift, there should be at least 0.060" clearance between the remaining open coils - and this should definitely be checked on the car.
Choosing the right springs is mostly dependent on the max expected valve lift to ensure there is no coil bind, and that the springs are stiff enough to prevent valve float with the cam profile at max expected RPM.
10-17-2011, 11:55 AM
#26
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Does everyone tighten down the rockers to 22ft lbs? I have read in a few places to tighten them down to 24-26. I am doing my measuring and checking the wipe pattern right now with my AFR's and Yella Terra rockers. When I tighten them down to 25ft lbs I get 1.4 or so turns with 7.425 known length TSP pushrods with LS7 lifters. It looks like that is good, about .065 preload. Not sure I want to go up to .090 preload.
10-17-2011, 01:11 PM
#27
Does everyone tighten down the rockers to 22ft lbs? I have read in a few places to tighten them down to 24-26. I am doing my measuring and checking the wipe pattern right now with my AFR's and Yella Terra rockers. When I tighten them down to 25ft lbs I get 1.4 or so turns with 7.425 known length TSP pushrods with LS7 lifters. It looks like that is good, about .065 preload. Not sure I want to go up to .090 preload.
