1948-1952 Shop Service Manual - - Hudson-Essex-Terraplane Club

ENGINE TUNE-UP 2 -11
VACUUM ADVANCE ADJUSTMENT:
Vacuum advance should be checked on a distributor test
fixture that has a controlled source of vacuum and a vacuum
gauge.
1. Place distributor in the distributor clamp and tighten
securely with the hand wheel at the right side of clamp.
2. Adjust the vertical screw so distributor shaft fits down into
the drive chuck.
3. Use special wrench to tighten the distributor shaft in the
drive chuck.
4. Connect red tipped distributor lead to binding post at the
side of the distributor.
5. Attach vacuum pump connection.
6. Turn cam lobe switch to Battery Check position. Tachometer
indicating hand should read in bar at right end of
scale.
7. Test distributor point spring tension scale. The spring
tension is 17 to 20 ounces on both the six and eight
cylinder distributors.
8. Turn on battery switch at left side of tester head.
9. With cam lobe switch in the 6-lobe position and distributor
contact points closed, the dwell meter indicating hand
must read in the black bar for satisfactory point resistance.
If the reading is in the red band, it indicates dirty
contact points, loose connections, or resistance within
the distributor circuit.
10. Turn the motor drive switch to right hand rotation and
adjust the speed control
crank until the Tachometer reads 200 R.P.M.
11. Adjust the distributor contact points until proper degrees
of dwell is indicated.
12. Turn graduated degree ring until the arrow flash appears
at 0.
13. Then check to see if all flashes appear at 60 degree
intervals for the Hudson Six and at 45 degree intervals
for the Hudson Eight. If the f lashes do not
appear to within one degree of the respective angles,
it indicates an inaccurate cam.
14. Turn vacuum switch to the "ON" position.
15. Set degree ring so arrow will be on zero at a most
convenient point to read.
16. Adjust vacuum regulator to obtain correct reading on
vacuum regulator for exact p o n t the vacuum advance
starts to operate, and compare with specifications. Adjust
the vacuum regulator to each specification and check the
arrow flash on the degree ring.
17. Watch the arrow on the degree ring as the vacuum
regulator is adjusted to the point vacuum advance starts
to operate. Compare the reading with specifications and
adjust the vacuum regulator to each specification and
check the arrow flash on the degree ring.
18. If the degree indicated on ring is more than specified, the
unit is advancing too quickly showing the return spring
is too weak.
19. If the degree indicated on the ring is less than the specifications,
the unit is advancing too slow ly showing the
return spring is too strong.
20. Vacuum advance characteristics are varied by changing
the spring pressure or by inserting or removing washers
under the end of the spring in the vacuum chamber.
AUTOMATIC ADVANCE CURVE:
1. Adjust speed control so that distributor will rotate at the
lowest R.P.M.
2. Set degree ring so arrow will flash at zero at a point most
convenient to read.
3. Increase distributor R.P.M. to correspond with specifications
marked "Start".
4. Check the R.P.M. required to advance the arrow flash to
the first specification given.
NOTE: Be sure the advance is opposite the rotation of the
distributor shaft.
5. Continue to check the advance curve R.P.M. against
degree of advance and compare this with specifications.