1957 Buick Engine Mounting Adjustment and Flywheel Replacement

Turn flywheel, making sure that crankshaft end thrust is held in one direction, and note run-out of flywheel face. Run-out should not exceed .015″.

If run-out exceeds .015″ attempt to correct by tapping high side of flywheel with mallet. If this does not correct run-out remove flywheel and check for burrs between flywheel and face of crankshaft flange. Remove burrs and recheck for run-out.

If no burrs exist install a new flywheel and recheck run-out. If run-out still exceeds .015″ check run-out of rear face of crankshaft flange.

After installation of transmission, test for engine vibration. If vibration has been introduced by installation of new flywheel make correction as described in paragraph 2-27.

Replace 1957 Buick Flywheel or Ring on Synchromesh Engine

1. Remove transmission and clutch assembly, being sure to mark clutch cover and flywheel so that the assembly can be reinstalled in its original position.
2. Remove flywheel, which is located in a definite position on the crankshaft flange by means of one dowel.
3. If the flywheel ring is to be replaced, drill a 5/16″ hole in the ring between two teeth and split the ring at this point with a cold chisel. Heat and shrink the new ring in place as follows:
   • Polish several spots on the ring with emery cloth.
   • Use a hot plate or a slowly moving torch to uniformly heat the ring until the polished spots turn blue (approximately 600° F.). CAUTION: Heating the ring in excess of 800 deg. F. will destroy the heat treatment given during manufacture.
   • Quickly place ring in position against shoulder on flywheel, with beveled end of teeth away from shoulder, then allow ring to cool slowly until it is tight in place.
4. Make certain that the flywheel and the crankshaft flange are clean and free of burrs that would cause run-out, then install flywheel.
5. After installation of clutch and transmission test 1957 Buick engine for vibration. If 1957 Buick engine has vibration that did not exist before installation of new parts, make correction as described in paragraph 2-27.

 

2-27 CORRECTION OF UNBALANCED 1957 BUICK ENGINE

Individual crankshafts, flywheels, and other rotating parts are dynamically balanced to very close limits in production. Completely assembled engines are also given a running test and balanced to very close limits by drilling the flywheel or by adjusting converter balance weights as required. For this reason, a converter pump should always be marked so that it can be reinstalled in its original position on the flywheel.

Some cases of excessive vibration may result from replacement of rotating parts. An extremely unbalanced condition should always be corrected by replacing parts which are abnormally out of balance or materially different in weight from corresponding parts. The following procedures are intended only for correction of minor cases of unbalance which may occur when individually balanced parts are replaced.

Critical Speed of Vibration

Determine the 1957 Buick engine speed at which the vibration is most pronounced, so that test at this critical speed may be made after corrective work is done.

1. Place car solidly on stands high enough to permit working underneath.
2. Connect a tachometer to 1957 Buick engine. Start 1957 Buick engine and with transmission control lever in Parking position increase speed gradually until a point is reached where the objectionable vibration is definite. Note engine RPM at this critical speed, then stop engine.

Correction of Unbalanced Dynaflow Engine

1. Remove bell housing cover.
2. Install one balance weight No. 1178109 (.060″ thick) under the head of two converter pump cover bolts, and tighten bolts to 25-30 ft. lbs. torque.

NOTE: Do not place a weight at a flywheel to converter driving bolt because these bolts are not long enough for addition of weights.

3. Run 1957 Buick engine at critical speed and carefully compare vibration with that obtained without the weight, then stop engine.
4. Mark location of balance weight on converter pump, remove weight and tighten bolt to 25-30 ft. lbs. torque.
5. Install the balance weight at other converter pump cover bolts and compare the vibration produced at critical speed.
6. At the point where the balance weight produced the greatest improvement in vibration install weights of proper thickness to eliminate objectionable vibration. Balance weights are available under Group 4.115 in several different thicknesses.

NOTE: When factory balancing of converter pump is changed to balance an engine, the pump cannot be used with any other engine.

7. Install bell housing cover. Remove tachometer and car stands.

Correction of Unbalanced Synchromesh Engine

If the vibration developed after removal and installation of clutch assembly, check all clutch cover bolts to make sure they are of same length and that each has one lock washer. Also check marks that were made when clutch was removed and disassembled to make sure that clutch was assembled and installed according to these marks. Make any corrections indicated by this inspection and run 1957 Buick engine at the critical speed to check results.

If clutch assembly and installation does not appear to be at fault, mark clutch cover and flywheel and remove clutch assembly. Run 1957 Buick engine at critical speed and check for vibration. If vibration is eliminated, the clutch is at fault and should be balanced as described below. If vibration still exists, however, it will be necessary to balance the flywheel on the crankshaft.

To balance the flywheel, insert one clutch cover bolt successively in each hole in flywheel and check results at each position by running the 1957 Buick engine. It may be necessary to vary the test weight by adding washers or by using a shorter bolt. When a proper weight and position has been found to eliminate the vibration, the bolt will be on the light side of flywheel. Remove the bolt and drill shallow holes in diametrically opposite side of flywheel, until enough weight has been removed to make engine run smooth. Use a 3/8″ drill and do not drill any hole more than 1/4″ deep.

After making sure that 1957 Buick engine runs smooth with clutch removed, install clutch assembly according to marks made before removal and again check for vibration at the critical speed. If vibration exists with clutch installed, install one plain washer under the lock washer of each clutch cover bolt in turn until a location is found where the engine runs smooth. It may be necessary to place plain washers on two adjacent bolts in order to obtain enough weight at the proper location to secure balance.