Relief/Safety valve bore dia.

[4sd911]

Is there a minimum and maximum diameter of the bore to the safety and relief valves. At the unworn area of the bore I measure 0.593 (15.06mm), how big can the hole get without causing a problem. If I try to hone the hole to remove a rig caused from piston movement will I be asking for trouble, I could just open the hole up at the end near the threads.

Edit: I should add the piston diameter is 0.589 (14.96mm).

[Flat6pac]

If you open it up, youre going to loose the pressure with the oil bypassing the plunger. Not to say its not available I dont remember oversize being a topic with the bypass.
Bruce

[4sd911]

I phoned a well known shop and asked about having the bore fixed, I told him that there was a worn ridge and burr caused by the movement of the piston, he suggested using a brake hone to remove the burr. This I assume will enlarge the hole.

There is actually a ridge worn in the bore where the piston stops and a burr that sits between the annular groove around the piston. If I push the piston against this side of the bore I can feel the piston grab at that point. With the piston stopped at the ridge the outlet hole is still closed.

I do understand that if the hole is to big low oil pressure could be a problem.

[4sd911]

OK lets change gears a little. Tomorrow I will call some local machine shops and see if they are willing to hone out the bore fabricate a oversize piston to fit. What should the clearance be between the bore and piston? Does my measurement showing .004" (0.10mm) look correct.