Engine Assembly

New rings and bores wear considerable during seating and gaps quickly get wider. No operating defects will be noted if gaps do not get greater than 3'z".
Carefully remove all particles of carbon from the faces of the ring grooves in the piston.
Slip the back side of the ring into the groove (see Fig. 12) and roll it entirely around the groove.

Fig. 13— Checking Fit of Piston Ring
If the ring is the proper width it will turn freely but must not be sloppy. If it is too loose, try another ring.
Always place oil control ring in the lower ring groove.
It is of the utmost importance that the rings be selectively fitted to each individual bore and the ring groove of the piston. A final test of the ring fit in the ring groove is that a .002" feeler should

Fig. 14— Piston Inserter
pass uniformly between the ring and the ring groove around the entire circumference of the piston. It should be impossible to pass a .003" feeler around this same circumference. Fig. 13.
In slipping the pistons back into the cylinders, use extreme care, do not force the rings into the
10bore. Compress the rings with a piston inserter, Fig. 14, until they enter the cylinder easily.
The gaps in the three rings should not be in a vertical line, nor should there be any ring gap over the piston pin, as the gases could leak by more easily at this point. Therefore, it is desirable to stagger the gaps so that they will be equally distant around the circumference of the piston.
Removing Piston Rings
The best method is to clamp the piston in the Piston Vise shown in Fig. 15.
Fig. 15— Piston Vise
Insert a table knife or hack saw blade, as shown. As the knife is slipped back of the ring and guided around the piston with one hand, the ring is forced out of the groove with the other hand.
Remove the piston rings over the top of the piston.
It will be found easier to remove the top ring first, then the center and lastly the bottom. NOTE: Do not remove rings over skirt of piston as this scratches the piston skirt.
Main Bearings
Genuine Chevrolet main bearings are steel back babbitt-lined. The babbitt is centrifugally cast or "spun-in" into the steel lining. This method assures a positive bond between the steel and the babbitt and also prevents the formation of air pockets in the babbitt metal.
The advantages of this type of bearing is that the expansion characteristics are similar to those of the parts that they come in contact with. This prevents loosening of the bearings. The thin wall of the bearing permits the bearing to conform to both the crankshaft and the bearing bore in the cylinder block, assuring a snug fit at all times.

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