Re: JPOR: Piston removal

[Ben Bargabus <ben_b@xxxxxxxxxxxxx>]

ridge reamers:

after an engine has been in service for a long time the cylindar walls
tend to wear down a bit but unfortunately they don't wear down all the
way to the top (the piston actually stops before it reaches that point)
so you end up with a "ridge".  If the ridge is great enough you can
actually take out a chunk of the wall when you remove the piston.  The
reamer is a simple hand tool that works much like a boring tool on a
lathe and cuts that ridge out of your way.  By the way, since we're
covering engine rebuild basics, cylindars also get tapered over time,
the large blast of compression puts more side force on the rings at the
top of the stroke than it does at the bottom of the stroke so the tops
wear out faster, if you have too much taper and put in your new rings
then they will break prematurely.  get and inside mic and measure the
taper before you put the pistons back in.  If it's out of tolerance
you'll have to bore the block.

ring expanders:

If you are VERY careful you can put the rings on by hand but most people
who are inexperienced in this will break a ring.  It is much easier to
just buy (or rent) the tool and do it right.  Rings are very brittle and
tend to crack in half quite easily.

ring compressor:

Same deal, the rings are designed to fit tight against the sides of the
cylindar (they actually push out against them and form a very tight
clearance gap which you must with a small file by the way).  Without a
compressor it's tough to get them down in the holes, some people think
that more force is the answer and end up either breaking a ring or
buggering up the top of the cylindar.  There are two types of
compressors, one cranks down and one is tapered, get the tapered style
if you can (but make sure you get it for the correct bore size).

Later,
Ben.