On Aug 17, 3:58 pm, wrote:
On Fri, 17 Aug 2007 08:14:50 -0500, "Jim Burns"

wrote:
I "think" the problem was when Lycoming switched from alum/bronze pin caps
to aluminum caps. I've been told there is no problem with either the
alum/bronze caps that preceded or followed the aluminum caps, nor is there a
problem with the aluminum "piloted" press fit ends that are pressed into the
pins. Superior also makes pins with press fit plugs, although they problems
with the pins cracking in an earlier version.

Superiors SL points out that you can not mix pins/plugs of different weights
on the same engine.

Can an A&P familiar with the different pins chime in?

Jim

Pretty much nailed it. Minor nits, the piloted pins don't "press" in,
they slip in quite nicely until the inside of the pin gets varnished
up.

Every once in awhile they just start shaving. Have seen issues with
ALL the types in service.

The shop is recommending pulling all cylinders and doing a top. Does
one cylinder having an issue with pin plugs mean others much (the IA
says so, I'm not sure). I'm thinking I just want to replace this
cylinder and then fly it. The oil analysis will show if there is
another plug wearing.

Am curious what the OP or his tech found that requires cylinder
replacement.

The IA said the cylinder was "2 one thousands" out of spec. Actually
one of the reasons we choose this cylinder to pull ( from the oil
analysis we knew we had to pull one of them do to progressively higher
AL counts), was that the cross hatching was gone on #1 (this is recent
because we boroscoped it at annual and didn't see this).
This engine has 1000 SFNEW in 1998 so I was not expecting to have to
replace cylinders. The IA did say that the bottom looks like a new
engine, no sign of any problems down there (we change the oil about
every 30 hours).
Anyway, the IA is recommending a full top and I'm not sure that is the
way to go.

-Robert