dads
12-10-2002, 12:19 PM
Dan Thought you might like this for the teck section.
This is a quick course on valve lapping. The head is a ford 4.9, the size will make it easier to see. Tools you need are valve lapping tool and valve grinding compound. The lapping tool is stuck to the top of the valve and held between your two palms. You move your hand back and fourth to spin the tool. Clean the valves on a wire wheel to remove the carbon. Do not try to remove the heat discoloring of the metal. Take the valve-grinding compound, put three match head dots on vale mating face at 12,4 and 9 o’clock. On the surface that comes into contact with the valve seat. You slide valve into place and spin vigorously back and forth with even down pressure not to hard your not drilling a hole. Do this for five to ten seconds, raze valve ¼ of an inch lower rotate again. Repeat this four or five times. Each time you do this you will hear the course compound grind to a smooth tone. Pull valve clean both surfaces inspect. What you are looking for is an even surface. No shiny spot that go a crossed the surface or long pits that cross the surface. Shiny spots are from warping. On valve, valve warping. On seat, seat warping. If you cannot remove defects in eight to ten tries they need to be ground by a shop. What you are looking for is good seal to stop leakage to bring compression back up. You’re not looking to remove all the pits.
http://Adam.Cheshire.net/~dads/pic/valve1.jpg
In this pic you are looking at a lapped valve guide and one that is not. The dull surface is the lapped one. In the pic it looks shiney.
http://Adam.Cheshire.net/~dads/pic/valve2.jpg
In this pic you are looking at a lapped valve you can see the pitting in the valve. No big deal. It will seal again. Lapping buys you time and lets you know if on the next top end job you do, you may have to grind.
http://Adam.Cheshire.net/~dads/pic/valve.jpg
This is a quick course on valve lapping. The head is a ford 4.9, the size will make it easier to see. Tools you need are valve lapping tool and valve grinding compound. The lapping tool is stuck to the top of the valve and held between your two palms. You move your hand back and fourth to spin the tool. Clean the valves on a wire wheel to remove the carbon. Do not try to remove the heat discoloring of the metal. Take the valve-grinding compound, put three match head dots on vale mating face at 12,4 and 9 o’clock. On the surface that comes into contact with the valve seat. You slide valve into place and spin vigorously back and forth with even down pressure not to hard your not drilling a hole. Do this for five to ten seconds, raze valve ¼ of an inch lower rotate again. Repeat this four or five times. Each time you do this you will hear the course compound grind to a smooth tone. Pull valve clean both surfaces inspect. What you are looking for is an even surface. No shiny spot that go a crossed the surface or long pits that cross the surface. Shiny spots are from warping. On valve, valve warping. On seat, seat warping. If you cannot remove defects in eight to ten tries they need to be ground by a shop. What you are looking for is good seal to stop leakage to bring compression back up. You’re not looking to remove all the pits.
http://Adam.Cheshire.net/~dads/pic/valve1.jpg
In this pic you are looking at a lapped valve guide and one that is not. The dull surface is the lapped one. In the pic it looks shiney.
http://Adam.Cheshire.net/~dads/pic/valve2.jpg
In this pic you are looking at a lapped valve you can see the pitting in the valve. No big deal. It will seal again. Lapping buys you time and lets you know if on the next top end job you do, you may have to grind.
http://Adam.Cheshire.net/~dads/pic/valve.jpg