Seting up valve springs is one of my personal favorite things to do. Getting them all dialed in correctly is important, especially if you plan on revving the thing within an inch of it's life.

If you have access to a valve spring tester and you can actually measure spring pressure at various heights- that's a plus and you can make small changes in installed height to even out small differences in spring pressure. If you've got to vary installed height by more than .025" to get even pressures your springs are probably worn out or have some other sort of quality control problems.

On new springs always cycle them once fully to coil bind in a vice with some brass jaws to keep from damaging them. Old hot-rodder's trick from way back that may or may not still apply to modern springs but I still do it anyway. Shakes out a little of the tension in a new spring (that it will lose anyway once you run it in the motor for a few minutes).

If you don't have a spring tester then you want to set them all up about as identical for installed height as you are capable and have patience for. Here's a little trick I've picked up along the way that might be of interest to you......

You gotta pull up HARD on that retainer to get the locks to seat fully, as they will on a running engine. That means NO snap mics. You need a good valve spring height mic like the one in the picture- somethign that can apply some pressure upward on the retainer and locks. Put oil on your locks and the inside of the retainer where they seat- so they can slide past eachother and really clamp down (again, as they will in a running engine). Also, oil the threads inside the valve spring height mic and on the top and bottom surfaces that contact the retainer and valve spring pocket. Turn the thumb-wheel on the height mic until it's TIGHT, using 2 fingers. Back it off a little, do it again. Do it a third time. Then just do it lightly snug and take your measurement. That will be a stable and accurate number.

You think it doesn't make a difference? OK, try the same thing the first time with dry metal parts and only just making the mic lightly snug on the first pass. I guarantee you'll be off by at least .025-.035" vs. doing it the way I describe above.

 

There is no measurable difference between using snap guages and an installed height mic - especially not .030", if you know how to seat retainers correctly. The correct way to set up spring heights is to get a baseline for spring installed with your guage or mic, then convert that to a stem installed number, then you can quickly measure all the other valves in less than a few seconds each with a stem installed dial indicator guage just like you measured the first int/exh and said 1.750" spring installed = 2.030" stem installed for example.

 

There is no measurable difference between using snap guages and an installed height mic, if you know how to seat retainers correctly. The correct way to set up spring heights is to get a baseline for spring installed with your guage or mic, then convert that to a stem installed number, then you can quickly measure all the other valves in less than a few seconds each with a stem installed dial indicator guage just like you measured the first int/exh and said 1.750" spring installed = 2.030" stem installed for example.

You really should only have to add the same shim to all the int or all the exh, becuase if your machinist cannot repeat stem installeds to less than .005" I would be wondering what else is wrong with the head...

 

Exactly.