Tightening Loose Bearings of Chevy Old Models
( THIS ARTICLE IS ONLY FOR CHEVROLET ANTIQUE CARS )
To tighten bearings proceed as follows:
Remove the metal under pan from frame.
Drain oil from oil pan by removing plug from bottom of pan.
Remove lower oil pan.
To tighten the crank shaft bearings on the Model “FB” it is also necessary to remove the sub-base by removing the cap screws holding it to the cylinder block.
Locate the loose bearing. By putting pressure on the connecting rod or crankshaft any looseness can be detected.Be sure to examine all bearings carefully as it may save you the trouble of again removing the lower crankcase.
Remove the cotter pins from the castle nuts on the bearing cap bolts.
Take off the bearing caps and lower half of bearing.
CAUTION : Be very careful in removing to keep the two sets of shims separate.
Remove an equal number of metal shims from each side of the hearing caps.
If it is found there are no shims between the main bearing cap and the crank case, the bearing cap can be removed, locked in a vise, and with a mill file, remove enough metal from the face of bearing cap to allow it to be properly tightened.
NOTE: The number of thickness of shims to be removed will depend upon how loose the bearings were.Replace the remaining shims, bearing caps and castle nuts. Draw the nuts up tight. Again test the bearings by putting pressure on the Filing bearing caps.connecting rods or crank shaft.
If any looseness still remains, remove the caps and take out additional shims.if no apparent looseness exists, turn the motor over by hand and note the effort required.
If its more than one bearing is loose, each bearing should be tightened separately and when the proper adjustment has been secured, loosen the castle nuts sufficiently to take the pressure of the bearings from the crankshaft.
Then proceed to the next bearing in the same manner.
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Not too tight
Considerable care should be exercised not to get the bearings too tight, otherwise there is danger of scoring or burning them. A scored or burned bearing must be refitted, which requires scraping and much additional time so be careful take your time and be sure you are right.
After the proper adjustments have been secured on all bearings, the castle nuts can then be tightened and the cotter keys installed.
Connecting rod bearings that are fitted too tight will often produce a piston or piston pin knock, providing the piston or piston pins are worn to any extent.
After replacing the oil pan and connecting the oil pipe, fill with an over-supply of oil and allow the motor to run idle under its own power for some time.
When you are satisfied that the bearings have “worked in” properly, start the car and run it very slowly for several miles.
A bearing which has been set up snug will heat readily at first, therefore the danger of scoring or burning is very great until the bearing has had time to “work in,” so take your time it may inconvenience you, but in the end it will save you many hours and unnecessary expense.
Tightening Main Bearings (Superior Model)
To tighten Main Bearings on Superior Model remove the bolts which hold the motor to the front and rear cross members, and with a jack placed under the motor, raise. to a sufficient height to allow bearing caps to be removed.
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Tightening Loose Bearings of Chevy Old Models Article Source – This article courtesy should goes to : Chevrolet Repair Guide of 1923 by Chevrolet Motor Company.