SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: 69kona on October 30, 2016, 02:34:19 PM
-
Just need a question answered to set my mind to rest . I finished up my bottom end build and put a set of used 455 olds Edelbrock heads in almost new condition. I checked push rod length and installed push rods. Im getting contact on center of valve stem . Got motor running and broke cam in. Went to re-adjust the rocker arms and noticed alinement issue on a few rockers side to side . But the roller is still covering the whole valve stem face. Is there adjustment in the guide plates or ?
Thanks
Sent from my iPhone using SoCal Jet Boats
-
Here's some pics
Sent from my iPhone using SoCal Jet Boats
-
Are you showing heavy contact patterns on the pushrods?
-
Are you showing heavy contact patterns on the pushrods?
GT there are no contact patterns on the push rods...
Sent from my iPhone using SoCal Jet Boats
-
Slowly rotate the crank and watch the contact of the roller to the valve stem, see if it wanders from one side to the other and also where the roller contacts the stem throughout the full fulcrum of the rocker.
It might be OK, but now is the time to find an issue if there is one.
GT
-
Ok I'll check it out ... Thanks for your input . Don't want premature wear on valve train components
Sent from my iPhone using SoCal Jet Boats
-
Ideally, you want the plane of arc that the rocker sweeps to be coplanar with that of the angle of the valve stem.
To help visualize this: a line is defined by two non-coincident points. Think of the centerline of the valve as this line. The two points can be any two arbitrary points coincident with the centerline of the valve, defined by the center of the valve stem surface where the rocker sweeps and the other being the center of the valve seat.
A plane is defined by three non-colinear points, defined by the two previously mentioned points on the valve and the third point being the center of the rocker fulcrum. This is the plane that valve inclination lays in. The first picture illustrates this "Valve Plane." Note, the centerline to the right represents the centerline of the rocker arm stud.
The second plane is defined by the center of the rocker fulcrum and the center of the arc that the rocker roller sweeps (as installed). The second picture illustrates this "Rocker Plane" drawn with .030" offset between valve stem centerline and rocker roller centerline.
The further out of coplanar these two planes are: 1.) The greater the the misalignment at mid and peak lift. 2.) The greater the side-loading on both the valve and the rocker, as the roller tries to lift up on one side.
My remedy, when the trick adjustable guide plates are not available, is to cut the guide plates in half with a thin cut-off wheel in a die grinder; align each rocker by shifting its corresponding guide plate half, and then TIG weld the guide plate halves back together. I try to get the rocker as straight as possible throughout the range of lift.
Verify that there there is no contact between the push rod and the block or head throughout the lift range.
-
There can be a little slop in the holes in the plates... Try loosening the rocker studs a little and see if you can shift them to get the rockers a little more over the valve. Looks like both rockers are shifted in the same direction... This ought to get them a bit closer.
Sent from my iPhone using SoCal Jet Boats
-
Will do.... Thanks for your help guys
Sent from my iPhone using SoCal Jet Boats