Hot Rod Forum : Hotrodders Bulletin Board - View Single Post - please help me diagnostic this problem
View Single Post
  #6 (permalink)  
Old 09-21-2012, 06:25 PM
cobalt327's Avatar
cobalt327 cobalt327 is offline
WFO
 
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Location: Atlanta
Age: 59
Posts: 5,037
Wiki Edits: 1616

Thanks: 128
Thanked 595 Times in 545 Posts
Having inadequate valve spring pressure can cause this. They could be allowing the lifters to pump up.

Be sure to check the lifter preload and geometry. Being that the valve train is non adjustable, the push rod length is critical.

Changes to the following will effect the p-rod length requirement:

Camshaft base circle diameter
Pushrod length due to wear or replacement
Milling heads/block
Different thickness head gaskets
Valve seat height changes from seat replacement or from valve seat grinding/cutting done during valve jobs
Grinding the tip of the valve stem when doing a valve job or different length valves
Lifter pushrod seat height due to different manufacturer
Change in rocker arm type or design, or ratio
Reply With Quote