REFLECTOR: Lycoming IO 360 C1C Valve Problem Question

[HYTEC45 at aol.com]

The valve spring/s force will keep the lifter unit from  overextending.  The 
leak-down comes through the clearance between the  piston O.D. & bore I.D. of 
the unit.  Normal oil pressure delivered  through the ball check keeps the 
lifter extended to prevent any valve train  clearance.  Check that you don't have 
a broken valve  spring.  However, even a broken spring should provide enough 
force  after shutdown with hot oil to cause leak down and eliminate over 
extension, but  something to check while your there.  Don't become a car dealer  
auto mechanic and be a "part changer", try to find the cause before  replacing 
anything.  Regarding a possible "sticking valve", when the  rocker pushes the 
valve open, it is not a direct inline force with the C/L of  the valve stem.  
With a worn or out of spec guide, the slight side  force can cause the stem to 
bind against the I.D. of the guide and  stick.  Removing the rocker arm load 
will allow the stem to re-aline with  the guide and everything works good by 
hand, but the problem is still  there.  Check stem to guide clearance per the 
SB.   A benefit of roller rocker arms are this side load is greatly  reduced. 
TEC 



************************************** See what's free at http://www.aol.com.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://www.tvbf.org/mailman/private/reflector/attachments/20070516/aa9b17cd/attachment.htm