Valve stem tip to rocker shaft vertical dimension

[Jerryl]

Can someone post the average vertical/height dimension/measurement from a stock untouched head from the rocker shaft (top or saddle/bottom of the shaft) to the tip of the valve stem?
I want to verify stock rocker geometry.


Edit;
Excuse the crude sketch.

 

[turbodave231]

I don't think you'll find that dimension published anywhere. However, the dimension for valve installed height (also called stem height) is typically measured from the spring pocket to the tip of the valve. The Buick Service manual does not list stem height although many other do list this information.

I'd like to know what the stock dimensions are myself .

 

[charlief1]

I just checked the Buick powersource and one other manual and it's not listed there. Sorry Jerry.

 

[Jerryl]

I don't think you'll find that dimension published anywhere. However, the dimension for valve installed height (also called stem height) is typically measured from the spring pocket to the tip of the valve. The Buick Service manual does not list stem height although many other do list this information.

I'd like to know what the stock dimensions are myself .

I just checked the Buick powersource and one other manual and it's not listed there. Sorry Jerry.

Thanks guys.
"Maybe" someone who is changing out a valve cover gasket on a low mile stock car can get a measurement like #3 in the sketch.

 

[bison]

It would have to be low mileage or the dimension will be off.

 

[Jerryl]

It would have to be low mileage or the dimension will be off.

Yeah, you are correct.
More less looking for a ballpark number, +0.010" (??)
I figure between "normal wear", "measurement system calibration", "method of measurement used", and "reading error", 0.010" should be OK?

 

[turbodave231]

I'm going to check AllData tomorrow (I have access at work/school). If I find the spec, I'll post it on this thread.

This is really an important dimension to have when doing a valve job. Everytime you grind the valve face or seat, this dimension gets bigger........and increases the lifter pre-load (pushes the plunger further into the lifter). It also changes the rocker to valve tip geometry.

Decking the block or heads also increases the lifter preload. The lifters only have so much travel and you could eventually be holding valves open.

Dave

 

[Jerryl]

I'm going to check AllData tomorrow (I have access at work/school). If I find the spec, I'll post it on this thread.

This is really an important dimension to have when doing a valve job. Everytime you grind the valve face or seat, this dimension gets bigger........and increases the lifter pre-load (pushes the plunger further into the lifter). It also changes the rocker to valve tip geometry. . . . .

Thanks Dave!
Exactly what I was thinking on the geometry issue . . . . .

 

[turbodave231]

Info from AllData:

Stem Diameter Intake 0.3401-0.3412 in
Stem Diameter Exhaust 0.3405-0.3412 in
Valve Installed Height 1.96-2.00 in
Face Angle 45° deg
Margin 0.025 in

 

[Jerryl]

GREAT data Dave! Thanks!
What surprises me more than anything is the 0.040 total allowable tollerance on this dimension. Guess target should be 1.980 + 0.020
Thanks again!!!