Re: Packard Tool J-2553, Need Tool or Specs.

Posted by Owen_Dyneto On 2011/5/13 12:44:21

PLEASE - read the shop manual. The 0.030 to 0.070 isn't the clearance for solid lifters, you'd hear them 5 miles away at that clearance and the engine would run VERY poorly.

The hydraulic tappet only has a certain limit of range, that is it has a limit to it's up and down range. When you replace valves, cut seats for valve faces, etc. you change the distance between the stem and the hydraulic tappet and thus risk running the tappet out of range. Too little clearance and you're run the hydraulic body into the lifter body and risk breaking the tappet or the base, or jamming them together.

You REMOVE the tappet body, replace it with a gauge block, and grind the base of the valve stem to give the 0.030 to 0.070, thus insuring that when the tappet is reinserted the lifter's range isn't compromised; that is, the remaining gap is within the tappet's range of movement!!

Yes, when the hyraulic tappet is energized with pressured oil, the clearance between it and them is zero. But that's not the issue.

I made and sold these tappet gauge blocks many years ago. As I said in an earlier post, if you want to borrow one, send me a PM.