Engine
Reconditioning Overview & Tips
For your 1929-1955 Chevrolet Straight Six Engine
October
14, 2002
Edited
by: James W. Burnes
Part
V: CRANKSHAFT, CAMSHAFT, AND BEARINGS
Bearing
overhaul on the older type engines requires line-boring equipment
which should be done in a shop specializing in this kind of work.
In later engines precision type shells are used as service replacement.
If
crankshaft is rough, scored, or excessively out of round it should
be reground to the nearest undersize that will clean up. Bearing
shells are available in standard sizes and undersizes of .002,
.010, .020 and .030 in.
If
there is any indication that the block is warped, semi-finished
shells should be installed and line-bored. Bearing clearance should
be .0015-.003 in.
Number
three main bearing takes the crankshaft end thrust. Be sure that
the nd play is in the tolerance of .003-.009 in.
CAMSHAFT
AND BEARINGS
The
camshaft runs in four steel-backed white-metal-lined bushes. If
the camshaft journals are more than .001 in. out of round, camshaft
should be replaced or re-ground. Camshaft bushes should be removed
and replaced with a special bar and shouldered sleeves.
Make
sure the oil holes line up with the holes in the block. Semi-finished
camshaft bearings can be line-bored (or linereamed with a special
reamer) to suit a new or reground camshaft. Ream or bore to a
clearance of .002 - .004 in. A new camshaft end plug should be
installed at the rear of the cylinder block. This plug must be
flush to 1/32 in. deep.
Read
Part I, overview of the straight six engine
Read
Part II, engine removal and reinstallation
Read
Part III, cylinder block and rod/piston assembly
