Distributor: Testing and Inspection

TESTING DISTRIBUTOR ON A TEST BENCH





Refer to the manufacturer's instruction at all times when testing distributors on a test bench,
The number on the side of the distributor is the Bosch part number.





1. Control unit
2. Ballast resistor
3. Distributor
4. Ignition coil
5. Test bench
6. Connecting lead to distributor
7. Power supply (14 V) Lightning bolt symbols indicate dangerous high voltage terminals

CALIBRATE TEST BENCH
Set zero at distributor shaft speed corresponding to zero advance. This compensates for the electronic advance from the impulse sender.





1. Zero set at (360 rpm)
2. Electronic advance
3. and 4. Centrifugal advance begins
5. and 6. Centrifugal advance ends
7. Absolute limit of ignition advance





CHECKING FIRING
Set distributor "0" to position which corresponds to firing of cyl 1.
Firing should be:
4 cyl: 0 - 90 - 180 - 270
6-cyl: 0 - 75 - 120 - 195 - 240 - 315 - 360
Max. deviation = +/- 1.5°.
Increase speed.
Check shape of arrows (or equivalent symbol depending on test unit).
If deviation is more than 2° this indicates that side play is too large.





CHECKING CENTRIFUGAL ADVANCE
Run distributor at 3.5 r/s (200 rpm). Calibrate meter. Increase speed and check that centrifugal advance conforms to specification.
If not, check that balance weights are lubricated and do not bind.
Also check springs.





CHECKING VACUUM ADVANCE
Run distributor at 10 r/s (600 rpm).
Calibrate meter.
Increase vacuum and compare value to specification.