Engine Assembly

Both of these important features of Genuine Chevrolet main bearings make for long life.
When it is necessary to replace main bearings, the clutch housing should not be removed from the cylinder block. This is very important, as the transmission pilot hole in the clutch housing is used in the alignment of the boring bar. In case it is necessary to replace the clutch housing, the new part must be assembled to the block and checked before main bearings are installed. The housings furnished for service are selected and are interchangeable with the production part.

Fig. 16— Main Bearing Boring Machine
Main Bearing Boring Machine
The unit consists of the following parts :
A— Support Bracket and Clamps B— Boring Bar Clamps
C— Boring Bar Supports and Ball Bearings E— Boring Bar Centering Bushings F— Clutch Housing Aligning Bushing —Two
sizes of this bushing is necessary —One for standard
models and one for master.

G— Clutch Housing Aligning Bushing Holder H— Cutter Tools
I— Boring Bar
J— Boring Bar Extension
K— Boring Bar Feed Support
L— Feed Nut Yoke
N— Feed Screw
0 Crank Handle
R— Feed Nut
S— Socket Wrench
T— Open End Wrench.
The operations are as follows :
1st— Support the crankcase in motor stand with bearing side of case up.
2nd— Remove old bearings and see that case is well cleaned.
3rd— Fit into the front and rear bearing bore of case the centering bushings "E," then assemble bearing cap and draw down tight shims should be left out.
Fig. 17— Checking Clutch Housing
4th— Slip Boring Bar, "I" through the centering collars —have crank end of bar to the rear end of crankcase.
5th— Assemble dial indicator and holder to clutch housing end of boring bar. See Fig. 17.
6th— Indicate transmission pilot hole in clutch housing. If this hole is true within .015" indicator reading it is O. K. If it is out more than .015" indicator reading the clutch housing must be replaced. See Fig. 14.
7th Having determined the alignment of the clutch housing, remove boring bar "I." Remove rear bearing cap and rear centering bushing "E." Insert centering bushing "F" in transmission pilot hole of the clutch housing.
8th Assemble clutch housing aligning bushing holder "G." Do not tighten securely until boring bar has been assembled in place.
9th— Insert the boring bar "I" through the clutch housing and bushings. As the boring bar is slipped through the bushings, also guide it through the boring bar bearing supports "C," placing two of the supports between the center and the front main bearings.
10th— Assemble the support bracket "A" down over the rounded end of the boring bar sup-ports "C" and clamp them in place to the case. Make sure they are just far enough away from the case bearing so the cutter can be fitted into the boring bar.
11th — With support brackets "A" now clamped to case, next tighten screws in boring bar clamp "B." This will now locate and hold in place true to center the boring bar supports "C."

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