Usage:
The new 5P2050 Checking Fixture can be used for taking accurate measurements of the relation between the pin bore and crankshaft bore on connecting rods. The fixture can be used for checking connecting rods after the pin boring operation, and for checking used rods for possible rebuilding.
1. 5P2050 CHECKING FIXTURE
2. 5P2051 POSITION ARM
3. 5P2052 CRANK MANDREL (4.00" TO 5.50") NOT SHOWN
4. 5P2053 CRANK MANDREL (2.62" TO 4.00")
5. PLUNGER EXTENSION (SEE APPLICATION CHART)
6. PIN MANDREL (SEE APPLICATION CHART)
5P2050 CONNECTING ROD CHECKING FIXTURE
Checking Center-To-Center Distance
(1) Use the chart on pages 9 and 10 to find the correct pin mandrel, crank mandrel, and plunger extension. Install pin mandrel (1), crank mandrel (2), plunger extension, and position arm (3) on the master or new connecting rod of known length. Put arm (3) in alignment with the centerline of pin mandrel (1), and tighten actuator (4) until the plunger extension and mandrel (2) are firm (solid resistance) against the connecting rod.
(2) Put the master connecting rod into position on the checking fixture as shown. Loosen knob (5) and move indicator holder (6) until the dial indicators (7) show about .010" less than one revolution.
(3) Put both dial indicators in the "zero" position by turning dial face (8). Remove the connecting rod from the fixture; turn the rod 180° horizontally and put it back in the checking fixture.
(4) If the dial indicators are still in the "zero" position after turning the master rod 180°, the fixture is correctly calibrated. If there is a new reading on the dial indicators, turn dial face (8) of the indicators one-half of the difference between zero and the second reading (Example: If there are readings of + .001 and - .001, set dials to + .0005 and - .0005). Remove master rod (9) from the fixture. Remove the mandrels and position arm from the master rod.
(5) If the connecting rod is being checked before being rebuilt, remove piston pin bearing (10) from the rod. Install the correct "bearing out" pin mandrel (1), crank mandrel (2), plunger extension, and position arm (3) as given in the Application Chart.
(6) If the connecting rod is being checked after being rebuilt, install the correct "bearing in" pin mandrel (1), crank mandrel (2), plunger extension, and position arm (3). NOTE: The pin bearing must be "cleaned up" (100% machined on the inside diameter) after the boring operation.
(7) Put position arm (3) in alignment with the centerline of the pin mandrel (1), and tighten actuator (4) until mandrel (2) is firm (solid resistance) against the connecting rod. Put the connecting rod into position on the checking fixture as shown.
(8) Make a record of the readings on the two dial indicators (7). Add the two readings and divide by two. The resulting average is the difference from the standard center-to-center distance. Refer to the chart on pages 9 and 10 for the maximum tolerances before and after rebuilding.
EXAMPLE I: (+ .003 and + .001) ÷ 2 = + .002 average tolerance.
EXAMPLE II: (+ .001 and - .003) ÷ 2 = - .001 average tolerance.
EXAMPLE III: (- .002 and - .004) ÷ 2 = - .003 average tolerance.
Checking Bores Parallel And Twist
(1) Install the correct pin mandrel (1), crank mandrel (2), plunger extension, and position arm (3) as given in the chart on pages 9 and 10. If the rod is being checked before rebuilding, the piston pin bearing (4) must be removed before checking.
NOTE: A master or new connecting rod is not needed to check bores parallel and twist.
(2) Put position arm (3) in alignment with the centerline of the pin mandrel (1), and tighten actuator (5) to hold crank mandrel (2) firm (solid resistance) against the connecting rod. Put the connecting rod into position on the checking fixture as shown.
NOTE: If the checking fixture has already been calibrated with a master or new connecting rod, omit steps 3 and 4, and go to step 5.
(3) Loosen knob (6) and move holder (7) until the indicators show about .010" less than one revolution. Put both indicators in the "zero" position by turning dial face (8) on the indicators. Remove the connecting rod from the fixture; turn the rod 180° horizontally and put it back in the fixture.
(4) If the fixture was not calibrated with a master rod, make a record of the readings on each dial indicator. Add the two readings together (both plus and minus), and divide the sum by two to find the bores parallel reading. Refer to the chart on pages 9 and 10 for the maximum tolerance for bores parallel.
EXAMPLE I: (readings of + .003 and - .001) ÷ 2 = .002 bores parallel.
EXAMPLE II: (readings of + .004 and - .004) ÷ 2 = .004 bores parallel.
EXAMPLE III: (readings of - .005 and + .001) ÷ 2 = .003 bores parallel.
(5) If the fixture was calibrated with a master rod, make a record of the reading on each dial indicator without moving the rod (not necessary to turn rod 180°). The total difference between the indicators (both plus and minus) is the bores parallel reading. Refer to the chart on pages 9 and 10 for the maximum tolerance.
EXAMPLE I: readings of (+ .003) - (+ .001) = .002 bores parallel.
EXAMPLE II: readings of (+ .001) - (- .003) = .004 bores parallel.
EXAMPLE III: readings of (- .004) - (- .001) = .003 bores parallel.
(6) Push one end of mandrel (1) against one of the locating surfaces (A). Use a thickness gauge (9) on the opposite end to check the clearance between the rod and the locating surface. Check both ends of mandrel (1) for possible clearance. The amount of clearance is the twist in the rod. Refer to the chart on pages 9 and 10 for the maximum twist tolerance.
