Paul,

   Is it feasible to use a solid case, instead of a split case using inside
   snap rings to separate the rotating elements?

   milo

   In theory yes because the rear flange is bolted on.

   But given what I little I know about overhauling
   piston engines bearing shells halves are a bit over size so when you
   torque the case bolts... the shells compressed slightly and are
   held securely in place.

   All you piston engine guys out there chime in on this.

   The other problem is the oil slinger near the front of the shaft
   but there is a work around for that.

   Paul Lamar


   Journal bearings as used for main and rod bearings in recip engines are built
   such that the pair has a few thousandths of crush. One or both halves will
   stick up from the housing half they are installed in when just seated by hand.
   The bearing surface at the joint area will be cut back a small amount so that
   when the bearing cap is torqued to final specification, the shell is pushed
   tight into the bore to prevent turning. This would flare the shell at the
   joint thus the imperceptable amount cut back to enable the shell to be round
   and not close up clearance at the joint.

   Dale Davies

In addition, the stamped sheet metal bearings are not perfectly round on
their own.  The crush fit drives them hard into the line bored hole so they
become round.

A bigger problem in aluminum where the hole gets bigger with
oil temperature than in cast iron.  You return cooled oil right into the
bearing shell on racing transmissions to keep the bearing and housing as
small as is possible.  Either into a hole in the shell or run two bearings
side by side with the oil hole between the shells.  You also use some form
of positive seal retention system.  Washers that extend out over the seal.

Or a thin plate held on with screws or springs.  I use a thin "O" ring in
the bottom of the bore that fits into the chamfer on the seal.  Then
non-hardening Permatex and spring powered hooks to hold the seal in GM style
t-400 tailshaft housings.  And I do cool the trans oil.  Notice in Hewland
tranmissions that even some roller and big needle races have notches ground
into the outer races that fit over tiny steel pins in the case to prevent
out races from walking around honing out the case bores.


Some builders use
flat head screws to retain the Mazda rotor bearings.  Right through the face
of the bearing.  6 per rotor.  Mazda rotor bearings a made from flat sheets
with a puzzle lock.  The bearing surface is ground away over the puzzle lock
area.  The bearings are not round until pressed into a rotor.  The old
racing bearings were round and made from steel tubing.

Lynn E, Hanover





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