How to set valve train geometry??

[FDK/mrpedrini]

Hi, there is probably a topic about this subject....just can't find it.. ...
I need to know what to do to set the valve train geometry on my 78,4 X 90,5 engine..
Any advice or technical articles are welcome!!!

Already thanks!!! kind regards, Dennis

[carlnolen]

 Pushrod length and rocker geometry are done at the same time. You are trying to accomplish two things: pushrod length and rocker height (if shimming the rockers is neccessary).  You are looking for the contact of the rocker pad onto the lash cap and the length of the pushrod. As the valve is at 1/2 lift, the pushrod and adjusting screw should be centered up. As a center line should go through the adjuster screw and pushrod at 1/2 lift.

Here's a good web site with pics for rocker arm geometry:

http://www.lunatipower.com/Tech/Valvetrain/HowToVerifyValvetrainGeometry.aspx

That technique works very well. You'll need an adjustable pushrod to experiment with on lengths. You will probably shim the rockers up and down looking for the sweet spot on the lash cap and adjusting the pushrod length as you go. Once you get the lash cap pattern to come in, your pushrod will probably be spot on too. Just watch the pushrod as you reach 1/2 lift and it will probably line up with the adjuster centerline.

Carl

[bugoff]

Try these links for some great info 

http://www.chevelles.com/forums/showthread.php?t=284771

http://www.mid-lift.com/TECH/TECH-Installed-G1.htm