Technical 354 Hemi Valve question

With stock valve train geometry being very important, valve length and assembled height ect. does anyone know what the distance from the spring seat to the tip of the valve should be, every time you do a valve job (cutting the seats) you change this length, what are the limits? I have a couple sets of heads, and the seat inserts are installed at different depths, if I know the stock measurement then I can compensate for the seat depths.
Thanks for your help

 

I don't know of the installed height of the spring is measured to the tip of the valve, but it's supposed to 1.700" closed.

 

No spec I've ever looked up had the measurement you request. What you want to know is the spring installed height, which is from the spring seat (in the head) to the installed spring retainer on the valve stem. You do not need to install the spring to attain this measurement. 1.700" would be this measurement.

 

The spring depth isn't important, because with a 'height mike' the machinest measures the depth and shims the springs to proper seat pressure. If the pocket is .040 deeper you shim to get proper spring pressure. Getting proper spring pressure is the more critical measurement.

 

I see that you are getting lots of answers about spring height, when that wasn't the question. However i don't know the answer either. I would think some good head shop with an older guy would know how much to face off your tips to restore your geometry.

 

Check the spring installed height It should be 1 55/64. If the valves are ground the number will be more than that the stems should be reduced by that amount. I think Chrysler valves should be 5" long when new for intakes and 4 29/32 ex.

 

Sorry, I read the question wrong.

 

...but you have a good answer.
The real concern is that the spring must operate within a certain min/max height.
On an EarlyHemi with stock valves..... open = 1.2" and closed = 1.7", same as later LA engines which is where a lot of our springs come from.
Do Not cut the spring seat deeper to fix a spring or valve problem...there are some thin spots under the spring even on a stock head.
If a hard seat is set too deep (valve too tall) then find a taller seat. If it sits proud (valve tip short) then make a deeper cut in the head or start grinding. It seems unlikely that the relative valve position would be so far out of whack on an average valve job that the geometry would suffer without some other indications along the way.
Again, on an average valve job, you should not be removing gobs of material from either valve or seat. If you have some serious damage then replace them.

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When I did heads I couldnt find the stem height spec for I just measured from the spring seat to the tip of the valve before I did any work.. measured all the exhausts and averaged the reading out then the intakes. After the valve job I ground the tips to get the before measurement and equaled them all out. I kept a note book with all the specs for future reference.. not the most scientific method but it served me well over the years. Knowing the before height really helped when putting in new seats so you could cut the seats to the right depth.