Fitting Connecting Rod Bearings

Fitting Connecting Rod Bearings

This article is only for Chevy Old Models 

Connecting rod bearings can be fitted to the crankshaft in the motor, or to a round steel arbor clamped in a vise and which is ground to the exact size of the bearing on the crankshaft.

The diameter of the connecting rod hearing on the crank shaft on Models Four-Ninety, Superior and G  is               1%  inch; on  Models FA, FB  and T is 1  1/2 inch.

Smear a thin coating of Prussian Blue on the connecting rod bearing of the crankshaft, or on the arbor.

Install  the  connecting rod on the crank shaft or arbor with the piston end hanging downward. Draw the nuts tight so that  the  bearing is snug on the shaft.

Swing the rod back  and forth several times.

Remove the cap and examine bearing for blue spots.

The  blue spots indicate that  the bearing and  crank shaft rub at these points only, which are known as “high spots.”  The desired result is obtained by scraping the bearing so that the crank shaft bears evenly at all points. This is an operation requiring much patience, so take your time, as it will pay in the end.

Remove “high spots” with scraper.

If a new babbitt bearing has been installed, be sure that the fillet does not hold the bearing away from the main part of the crankshaft bearing. The purpose of the fillet is to take care of side thrust; however, unless care is used not to remove too much metal, this will not be accomplished.

In other words, a properly fitted bearing is one where the babbitt touches the crankshaft evenly and at all points, including the fillet.

Repeat the operation until all “high  spots” are removed and the bearing surface is smooth and touches the crankshaft at all points.

With the point of the scraper remove all burrs or obstructions from the oil grooves.  Remember that these grooves are to properly spread the oil over the bearing surface; therefore, it is necessary that there be no obstruction, also that they are deep enough.   See that the oil hole is clear and lines up with the hole in the cap.

When the bearing has been fitted to the shaft, lubricate it thoroughly so there will be a film of oil on the bearing when the motor is started.

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Fitting Connecting Rod Bearings article Source – This article courtesy should goes to : Chevrolet Repair Guide of 1923 by Chevrolet Motor Company.