Packard Forum Index » V-8 (1955-56)

Quote:

The bottom of the lifter is slightly crowned and the camshaft lobe has a slight taper. When running, this causes a rotating force on the lifter so that wear is evened out over both the lifter bottom, cam lobe face and other parts.

Unfortunately, due to manufacturing variance, this also causes both of those surfaces to "mate" in a slightly different way than it's companions. If you substitute a new lifter to a worn lobe, this usually causes accelerated wear on the lobe due to the mating mismatch. This is what usually causes a "wiped out lobe." Now you've got bigger trouble than you had before swapping in the new lifter.

Craig

Thnaks, Craig, for the explanation. Makes perfect sense to me now.

Here's one more cam/lifters caveat:

If you disassemble an engine and plan on reusing that cam and its lifters, you MUST keep the lifters in the same order as originally installed. Of course, the reason is the same as I described above.

This rule does not apply to pushrods, but it does apply to rocker arms, unless you are going to resurface them.

Craig

I am sending the cam out to Isky to regrind for me. Napa wanted $9 these days. I just ordered the set from EGGE. they ended up being a little over $7 each.

Agentx66x wrote:
Quote:

Can you let us know what profiles (duration, lift, lobe center) are applied? Also, who chose them, you or Isky?

Craig

The numbers that I have seen from another Packard web site are these.

Manuf ID Int dur Int lift Exh dur Exh lift
Packard 440786 250 0.374 250 0.374
Packard 6480581 256 0.398 252 0.388
Isky E-2 Mechanical 256 0.420 256 0.420

I was going to ask Isky to make it as much as possible with out having to change any internals. I will post the numbers on my grind as soon as they figure out what can be done.