oiler holes in piston

[yellowbeard]

hey guys, just sent my cylinder off to be decked (big bore kit) and ordered a piston from the guy off of e-bay. Will I have to drill the three little holes in the piston for it to oil. wiseco piston. thanks Joe

[TeamGeek6]

My R piston didnt, as i recall, some did, and it was on an instruction sheet with the piston. check the wiseco website. Itll fry without them if theyre needed. if they are drilled, make sure to remove the burrs.

[tecat-z]

They are for lubricating exhaust bridge. This area expands at a faster rate than the surrounding area, and increases the chance of seizure. The holes reduce this occurence. Dummy up piston on rod without clips and no rings. Set cylinder on and trace on piston outline of bridge with soft lead pencil. Then you know exactly where to drill holes. I usually drill 3-4. I do this with all bridged exhausts that haven't been clearanced in that area.

[NINJA]

I've seen a few engine builders relieve the exhaust bridge .0005"-.001" also to reduce the chance of seizure.