Camshaft/Valve Question. Need Your Opinion.

[TOONAH]

Just received my 1G Head back after paying $1000 to have it CNC ported. Boy! am I sorry I spent all that money for nothing. It looks like he just skimmed a few thousandths out of the bowls and ports. I was promised the work would increase the flow by 15-20%. Well we will see. I just installed the exhaust camshaft. A brand new Blox Billet 272. Knowing that some of the valves will be partly open with the dowel pin @ 12 O'Clock I did the work with the head deck sitting on some nice thick dense foam. Any way I torque all the caps down by about 5 lbs ft (might have to take it off again). I examined the #1 valves by shining a bright light at them and peering into the exhaust port on #1 I see no light. Good. They should be both fully closed. #2 are equally partly open. #3 are fully closed. #4 are partly open, so they should be.
But!!! Right away I can see that one of then is quite a bit more open than the other. Poop! I hear myself say to myself and I feel my sphincter tighten. That cannot be right. The cam lobes for each cylinder are identical are they not? So both valves should be at the same height? Right? I bring my calibrated micrometer precision swiss eagle eyes to focus on the height of the lifters. Both identical in reference to the head and the internal piston travel is the same. OK! Perhaps the guy didn't shim the spring height correctly or the cam follower
bearing or tip are worn significantly.
What do you think? Each of the paired valves for any given cylinder must always be at exactly the same height right?

 

[Defiant]

Supposed to be. However, grinding or cutting the valves and seats means they will probably vary unless the stems are trimmed to make them match exactly. Before running, the amount your lifters are pumped up will vary from one to another as well.
In the real world, I'd doubt you could measure an effect in them being different.

 

[Freerevving]

It really depends how much it's off... most likely (99% sure) you'll be fine after your lifters fill... whatever slack there is between the valve retainer and the lobe should be compensated with the hydraulics... As Defiant was saying, don't worry about it.