Worn cams = worn rockers

Probe Dude probedude@hotmail.com
Wed, 30 Jan 2002 14:13:42 -0600


Joe,
You've completely misread my message, what you now wrote and what I wrote
are saying exactly the same thing except for that you have not stated
mechanically why worn rockers would make less power, just that you changed
them and it helped.

I specifically said that the total lift of a cam is the difference in height
between the base circle and the lobe for a cam. The rocker at the point of
contact with the camshaft will move this height.  I also specifically said
that the HLA by extending itself under oil presure will eliminate any
clearance (in your words 'slack') between the point of contact of the rocker
and the cam at its base circle position and after that point it is
imcompressible so that any 'lift' of the cam is applied to the valve tip
(except for the rocker arm ratio).

I never said the HLA knows about the cam lift.

Reread my message.

Now, draw yourself a picture.  As you and I both said, if the rocker is
worn, the HLA will take up the 'slack'.

So, for a worn rocker to affect lift the point of contact for the cam to the
rocker would need to move.  This would change the mechanical ratio of the
rocker and if indeed this happened to you would have INCREASED the ratio to
give you even more lift.  (cam timing would change too)  However the rocker
would have to be seriously worn out to appreciably move this pivot point.
How deep is the wear?  What is the distance from the HLA to the cam pad to
the valve tip?

>Then by your definition, anyone with cams is wasting their time.

>The lifter does not know about "lift" or measurements. Here's how the
>lifter