Posted by Joe S. on January 11, 2000 at 21:26:42:
In Reply to: Venting posted by Daryl on January 11, 2000 at 17:19:20:
All that one needs are holes in the pistons that line up with the to-be-added tubing when the pistons are in the "up" position, and these holes should not line up with "active" ports when the pistons are in the "down" position. The larger the holes, the more effectively the slides are vented. Drilling should be started with a small spring punch to locate the bit, drilling first with a small bit, and then larger ones. A drill bit stop should be used, for obvious reasons. The holes should also be de-burred very gently and carefully.
If your Willson pistons have slight circular discolorations on their surfaces due to mild corrosion, those circles can be used to show one exactly where to locate the vents.
Select with care the person to do the job...It matters.
uhhh...not much more to say 'bout it :-)