Packard Forum Index » Post-War (1946-54)

Quote:

Humanpotatohybrid

Thank you for the lessons in history, chemistry, physics, fluid dynamics and budgeting!

This is starting to make sense to me, which helps as I plan my transmission project.
My current thoughts:
-Tear down transmission/s for inspection. (I have the transmission in my 53 Cavalier, the transmission out of my 53 Patrician parts car, and a club member has a transmission out of a 53 Clipper I can get as well.) Plan A is the rebuild a transmission for a swap in the spring and leave my car intact until then.
-Get a rebuild kit and maybe a new clutch plate, along with any other parts required.
-Continue running Type F ATF.

Isn't owning a classic car, and lighting $100 bills on fire, the same hobby?

Quote:

It would seem that if your DDC was opening on part throttle before that it was either a bug, or the way the throttle valve was adjusted. I would be inclined to think the latter as it should be the throttle valve that disengages the DDC. Maybe your throttle was set to open the DDC at almost full throttle, rather than "beyond full throttle". I know you experimented with this, and I think the result was that you were still not able to get the DDC to disengage, which is peculiar.

I still have to go out for a test drive, maybe later today after work, to see how my transmission reacts when I put the pedal all the way to the floor. I may need to fine tune the throttle valve adjustment again to get the DDC disengage at the appropriate time. It seems like it would be a fine line between getting the DDC to open at the correct time, the throttle valve not opening too much too soon, and maybe there is even the possibly of the throttle valve preventing full throttle if not adjusted correctly, which could be problematic for the operation of the 4 bbls.

I wonder if there would be an advantage to setting the throttle valve's open position, rather than it's closed position? That is, move the throttle linkage to beyond full throttle and lock it in that position. Then set the throttle valve so it is in the kick down position. A more complicated process, but maybe it would help ensure the DDC disengages at the appropriate time?

I need to do some experimenting!

Maybe the best idea is to disconnect the throttle valve from the throttle linkage and have a seperate linkage to a lever on the dash that I can control manually. Throttle valve wide open for performance mode, half closed for normal driving and all the way closed for Sunday driving mode. It would need an appropriate name, such as, Select-o-matic. (Not to be confused with the jukebox.)

53 Cavalier wrote:

I wonder if there would be an advantage to setting the throttle valve's open position, rather than its closed position?

I think you need to review the operation of said valve. It is a pressure regulating valve which when correctly adjusted, produces an output pressure proportional to the throttle opening. The exception being when you are at full throttle, you can hit the gas even more, which will not change the engine operation, but in that case the valve admits full pump pressure to its output. So I'm not sure you have a proper understanding of the operation.

That is, move the throttle linkage to beyond full throttle and lock it in that position. Then set the throttle valve so it is in the kick down position. A more complicated process, but maybe it would help ensure the DDC disengages at the appropriate time?

To be honest I see no advantage to this compared to the standard iterative adjustment. The important point is the alignment of closed throttle and of full throttle/entering kickdown, not the physical limits of the respective linkages. While you could visually inspect the carburetor, evaluating the transmission setting is only possible either by driving the car or doing a pressure test.

I need to do some experimenting!

Maybe the best idea is to disconnect the throttle valve from the throttle linkage and have a seperate linkage to a lever on the dash that I can control manually. Throttle valve wide open for performance mode, half closed for normal driving and all the way closed for Sunday driving mode. It would need an appropriate name, such as, Select-o-matic. (Not to be confused with the jukebox.)

This would no doubt be a good learning experience of why the throttle valve exists and consequently why no one has ever done this.

Went for a test drive to see if could get the DD to disengage after it had engaged, but no dice. I did go through all the linkages earlier this summer and set them as per the service manual, but I'm going to double check them. Maybe the throttle valve is not moving far enough to disengage the DD at "beyond full throttle."

These are the speeds my DD engages and disengages.

When slowing down, no throttle, it disengages around 13 mph.
With very light throttle it engages around 20 mph.
With medium throttle in engages around 40 mph.
With full throttle it engages around 51 mph.

Other than not kicking down, the transmission seems to be working as it should.

Think your throttle pressure is a touch low. I forget the speeds they intended but 20 is slightly low.

Quote:

That makes the most sense. I'm going to review the all the settings and see if something is off, it wouldn't take much.

Quote:

Thanks, but the use of available standard gauges and the additional electrical requirements and functionality will dictate the form factor.
The PU-300-2 will be similar, but...

Has everyone checked their Throttle Control Rod length per Service Counselor Vol. 29, No. 4 page 26 of April, 1955?

Good point, that rod having an inaccurate length will cause nonlinearity in the throttle pressure. It should be within 1/16" of the intended dimension, between centers. Though I wouldn't expect that to be a problem here per se.

Attach file:

---

  extension linkage.png (114.00 KB)

Quote:

It could also lead to incorrect relative start and end positions.

With one measurement we could move from "expect" to know and remove one variable from the equation.