Help me understand what I'm missing?

[megavites]

help me understand what step I might be missing. In another thread New rebuild....but tic..tic...tic

I explain my new build with all new valvetrain. I measure valve lash w/rockers at:

Intake Exhaust
#2(0) #8(0)
#1(.003) #4(0)
#8(.003) #3(.017)
#4(.006) #6(.043)
#3(0) #5(0)
#6(0) #7(.011)
#5(.012) #2(.014)
#7(0) #1(0)

so I measure valve stem height and add spring shim and oddly enough, my taller valvestems also have the biggest valve lash gap?? Seems opposite of what it should be??

When I measured lash, I bumped motor until no movement on that rocker to be sure its on basecircle. Rotating 90 deg and measureing was not putting next valve on base circle,

I presume due to custom performance cam (whiplash).

So I have .032” spread from on valvestems and anywhere from zero lash to .043 gap at rocker. Preload should be .080-.085.

IF I go with a .075” longer pushroad, preload would range from .032 to .075.

Is there anyway around this other than adjustable roller rockers to take up the slack?

I’m going to re-check again (Vernier depth gauge) the stem heights as I did vary by .020-.030 with my measurements when rechecking each measurement.

 

[DesertRat]

Som-ting-wong.
One start would be to pull all the rockers and check installed valve stem height for uniformity-both sides.
I use the 90 degree method for setting my preload but I question if it would be accurate enough for what
you are doing. The spread you are measuring speaks to an underlying problem that adjustable rockers would
just hide. My $00.02-------------------Good luck!

 

[Mopar Tim]

^^^Agree

 

[brian6pac]

Is the intake off ? The preload should be measured at the lifter plunger.
If you want .080 preload that means the plunger is down from the snap ring .080

 

[fatbaldmoparguy]

Spring pocket depth can vary quite a bit on factory heads. If the stem heights look reasonably even with a straight edge, your measurement from valve tip to spring seat .020-.030 variance may not be out of the question. Using a longer pushrod would take up the slack. Another fix would be using lash caps which are normally found in .060 or .080 thicknesses. Preference would always be to have lifter preloads fairly even, but as long as the lifter is preloaded and not bottomed out, I wouldn't worry about it (at least not worth pulling the heads to correct).
It may be a good idea to pull the lifter on #6 exhaust to take a look since it is so much looser than the rest.