For flat tappet hydraulic cams, I have two test lifters that have their guts removed, and a solid spacer inserted to keep the button down about .030 in the lifter. I also have done the same for hydraulic roller cams. I always do the push rod lengths with the engine on the build stand, and no intake manifold in place, E-O, I-C method and a rocker arm tool as well.

I am big on making my own tools, and have the machines to make them, but modifying a pair of lifters to set the button correctly isn't that hard to do.

 

I already replaced the springs with weak test springs. Might that be enough to get a good reading?

That is all you need to do.

 

If you have new dry lifters test springs will easily compress the lifters. Stick with the solids

 

Vince,


Not sure what test springs you use but the ones I have will not collapse a new, dry lifter. If the intake is off you can watch it anyway to see if the plunger is moving. Worse case put the lifter in a can of oil and pump it up.



The big problem with using any lifter other than the exact one you plan on having in the engine is that pushrod seat heights vary all over the place. Especially between hydraulic and solid lifters. Probably should not be that way but it is a fact of life

 

If solid lifters are used to check a hydraulic cam, make sure the push rod button height in both the solid, and hydraulic lifters are sitting the same height from the lifter to lobe face. Some solids have buttons sitting lower in the lifter, and if those are unknowingly used, the push rod will end up the wrong length.