Y block overflow tubes

[Ole Don]

Some have questioned my overflow tube change. Below are pictures of before and after. The after pictures show hard chrome shafts sold by John Mummert, I bought these in 1999 and assembled low mile unworn 1.54 rockers. The first pictures shows rockers that came off an old well worn Y block.

The second picture shows well worn shafts, with much more wear on the left end.

The third picture shows the shafts on the engine I just sold. Run hard and raced several times since 1999, there is a witness mark, but no wear on the shafts, just a nice film of oil.

Picture four is another part of the same shaft.

Picture five is the stand where the oil goes up. Another story will tell why there was way to much oil up top. The hole in the stand is the right size to tap 1/4- 20 and put in a plug with a 1/8 orfice.

Picture six is the trick I have been talking about. Cut the overflow tube to get a square end, and debur the inside. The ID is the right size to tap 12-24. If you buy a screw with a phillips head, the screw will guide the 1/16 drill bit, drill the length of the screw and debur. One drop of Locktight on the threads, screw it in, and blow through it right away to be sure Locktight didnt plug the hole. Do a trial fit to make sure the OD of the screw head isnt too close to the pushrod, some grinding may be required. After this change, at hot idle, you should see as much oil out the left rockers as on the right. These rockers and shafts should now last my lifetime and one more guy after I am gone. Total cost for this change is about a half a buck.