Valve spring pressure

[Rizzle]

Since you've got them apart to deal the the shims, is it possible to verify the springs to make sure they still match spec?

[MadBill]

Good point; surge puts a lot of stress on a spring...

[bobalattie]

Gonna get locator shims, and recheck the spring pressures and set them to 1.700~ which will be abt 145 on the seat and gonna switch to a thicker oil incase the lifters are bleeding down..

The only thing I can see is the lobes are aggressive and need more spring psi to control the valve train..

The pushrods don't show any abnormal wear and the valve stems show a nice tight pattern where the rocker is on them.

[KnightEngines]

.500" lift on a clevo is not much, even with a hyd cam - 1.72 rocker ratio on them things.

I'd be thinking lifters bleeding down or spring surge.

[cgarb]

Qurstion here, those spring specs 130 seat/340 open would be right in the ballpark for a hydraulic roller set up for what i've seen around here and other places. Ive heard of more pressure than that with a hydraulic roller even. If those pressures won't collapse a hydraulic roller lifter why would it collapse a flat tappet lifter? What is different in the hydraulic plunger in a roller lifter as to a flat tappet lifter to make it handle more spring pressure?