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KICKDOWN ADJUSTEMENTS on TORQUEFLITE "cast
iron"
Since i overhauled some Torqueflites i always had some
problems with the "forced kickdown" (or forced downshift 3-2 or 2-1 or 3-1).
Generally it does not function properly and one depresses in vain on the
accelerator, the car does not downshift..
VERY
SIGNIFICANT: on all the "old transmissions" (before '70) the kickdown
occurs only in the last 1/10 inches before the pedal goes to floor. If you
accelerate hardly but without going "to the floor" you will not have a kickdown
!
For a few weeks I have studied well the question, send
requests to the mailing lists and made various tests.
Now I have a correct kickdown on
my Imperial !! It's just a matter of adjustment but NOT AS INDICATES IN the SHOP
MANUAL . Only problem, as my transmission upshifts badly from 2 into 3 (lack
of synchronization between release of KD band and engagement of rear
clutch) I have it also in kickdown 3-2. Thus my trans. should re-overhauled this
winter. But at least it "(forced) downshifts" now !
Problem solved (at 90 %) : bad kickdown band adjustement (with manual
adjustement...), i'll let know what happen on mailing list.
The various methods of the FSM are described on the
pics A-B-C-D-E below (click to enlarge). Approximately, here
what is indicated (I summarize):
- check if the accelerator pedal has a 118° angle
to horizontal (or 115 or 114, that depends on the model or FSM)
- Run engine until normal temperature is reached then
stop. Check for choke being fully opened . Set idle to 500 rpm.
- Loosen the carburetor throttle linkage nut on the carb. rod
("B" on left pic)
- Move the rod rearward against idle stop (in trans.).
- With rod preloaded and in line, lock the adjusting nut
But this method doesn't work on my car !
If i make the FSM adjustement the transmission throttle lever
can't go to "kickdown" position (all the way backwards) when the accelrator
pedal is floored..
I advise you to first test the FSM method
and if it doesn't work (lack of KD), take a look at my method (bottom of this
page)
| A |
B |
C |
D |
E |
 |
 |
 |
 |
 |
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'57-58-59 adjustements (shop manual) |
another '59
adjustement |
300C throttle linkage adjust. |
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brief technical pics and checks
on a disassembled valve body : various positions of the "throttle
lever" according to the kickdown valve position |
Note: on all pics o this page the "throttle
valve spring" has been removed for purpose of easier pics. This spring is
between kickdown and throttle valves , see position on pic # 1 and pic 4c.
Picture 1 : "release" position (throttle lever on
"stop" adjusting bolt). The port A is closed by k.d valve large diameter.
You can seen a part of this large diameter at the left of A . The
"check balls
port" has been tracked on the other valve bodies and yes it leads to check balls
"1-2" and "2-3" which are in the lower valve body then to
shift valves.
According to the pic, this check balls port is in relation with the "vent" port via spring and small
diameter k.d. valve
Click to enlarge
| 1 |
1a |
1b |
|
 |
 |
 |
 |
| Valve position |
1 3/4 " (refer to pic at
extreme right to know
how i take mesaurement) |
How i measure at throttle
lever: between front of cable housing (at cable opening) and larger
diameter of the throttle lever |
Picture 2 : As it is with light
throttle (1/4 maybe ?). The throttle lever has pushed a little the k.d valve. Port A remains closed
| 2 |
2a |
2b |
 |
 |
 |
| Valve position |
|
2
9/16 " |
Picture 3 : You push hard on the gas
pedal so throttle lever pushes on k.d valve stem (you feel resistance because
you must compress the valve spring). But the port A is always closed (the
larger diameter hasn't still open the port, see pic) ... So no kickdown
| 3 |
3a |
3b |
 |
 |
 |
| Valve position |
|
3
1/4 " |
Picture 4 : maximum travel of throttle
lever , the k.d valve is all the way in and the valve spring is completly
compressed (need a lot of strenght..). Now the port A is open and
throttle pressure can go to the check balls and 1-2 / 2-3 shift valves. The "larger
diameter" k.d valve closes now the opening between "check balls port" and vent
port.
this is the kickdown position
| 4 |
4a |
4b |
 |
 |
 |
| Valve position |
|
3
9/16 " |
- Check , with pedal floored, that the butterflies of the carb are fully opened and that the carb linkage is bottomed (all the
way forward) . You can shorten a little the accelerator pedal rod from under
the car. It's a very important step because if ther's something who prevents
the pedal to be floored (i.e carpet or mat) you'll never go to KD . 118° or
115 °, don't worry, you must have a complete travel before floor.
- At trans., remove the "accelerator shatft to transmission
rod assy" (cotterpin) , see pic at top of the page, and check the measurements
given in pics # 1b and 4b (extreme positions). Normally you'll find the
same than mine . Anyway ther's no adjustement...
- Move the throttle lever against its rear stop (KD
position as in pic 4b) , have an help who floors the accelerator pedal and
check if the cotterpin shaft of the rod is in line with the throttle lever
mounting hole. Best is to have the rod a fraction of inch further from the
throttle hole.
-
If adjustement is to be made, shorten (rarely..)
or lenghten the rod at locknut
"A" or"A" on pic below. Yes, the manual says: the purpose of
this adjustement is to allow for variations between chassis and engine
assemblies (..) and should not be used for making throttle linkage adjustement.
But in my case it was the only adjustement which works ! Check again the
adjustement and tell to your help in car to release and floor several times
the pedal. When the pedal is 95 to 100 % floored, the throttle lever must
be all the way rearward.
After this adjustement, if the pedal is released you'll see that the throttle
lever doesn't bottomed on "idle" stop (like 1b pic) but rather at an
intermediate position between 1b and 2b So if you follow the FSM manual with
throttle lever on "idle stop" you never go to KD position.
Now test the car ..
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