Packard Forum Index » V-8 (1955-56)

HH56 wrote:
Absolutely get in touch with Mr Pushbutton for his thoughts on the subject but if you want one of his rebuilt stock Packard units, unless things have changed in the last year or two I believe he may have an arrangement with one of the vendors to handle sales. The last time I spoke with someone buying a rebuilt unit they were also quite expensive -- and much more so without an old one to return.

For my two cents, I think the idea has merit as Packard actuators do have some issues that might be able to be eliminated with something plug in but a bit more robust. If you come up with something plug in that can use stock PBs, not only could it be used with a stock Ultramatic, possibly with a slight mechanical change and a bit of different programming it might also be adaptable to those who might want to or have already converted to the GM transmissions. There has even been some thoughts of using an 80s era Rolls Royce actuator for the GM conversions.

Regarding your question on strength: the original actuator was a bit weak in one area. It was fine for changing from one gear to another 99 percent of the time but if the car was parked on an incline or hard against a curb with tire pushback, with force of the tire or the weight of the car pushing against the parking pawl, the motor often did not have enough power to pull the pawl out of the parking gear. In those situations the car was locked in park until some means was found (often a tow truck) to remove the weight from the pawl.

On the speed, I doubt if anyone has measured it precisely but from this video posted by Mr Pushbutton it appears to take 2-3 seconds.

For whatever you come up with for a drive, since you are going to use a microcontroller setup to activate it, I think it would be good to go with some kind of direct optical encoder feedback off the actuator and have the microprocessor count pulses to determine exactly how many complete or partial revs of the motor it takes to determine where to stop. After spending years working on medical equipment that relied on precision potentiometers to determine positions of various items, I will disagree with Pgh Ultramatic on the point of trying to rely on a varying analog voltage to precisely control the stop points. Granted, it might be easier and maybe less expensive but even the most precision of pots do vary slightly in repeatability. A bit of corrosion on a connection, wiper, or in the suggested push button divider circuit can also affect a voltage enough that it could change stop points enough to matter. While the Ultramatic is not nearly as critical an application, the issue was noticeable enough in a clean environment so unless you get sealed components and take extra care with connectors I would wonder how the harsh conditions -- heat, vibration, dirt, grease, moisture, etc -- in a car would contend. The downside to using digital and microcontrollers is to remember that power in cars of that era was quite dirty. There was no consideration given to surges and spikes caused by relay or switch contacts operating and motor brush noise will be a serious issue. You will need to filter the heck out of things and even then, if a long run is involved, your 3.3 volts could be seriously affected.

Packard's fingers did a good job of finding the precise place to stop and I would try to duplicate that precision as much as possible. Optical sensors positioned much like the fingers might work but they would have to be mounted on a special new support which might be hard to place and also be weather resistant.

To go along with concerns about electrical position error, I would also suggest placing the actuator at the transmission to avoid introducing any mechanical error via slop from the cable and attachment points into the mix. Since the detents are part of the valve body, unlike the manual handle where you can feel if slop has developed or if you are fully in a position or not, if the motor stops where it thinks a gear is positioned but cable or mechanical slop adds an error and the motor has stopped with the valve between detents all kinds of problems will result.

No idea which type mechanisms you are considering but there are some rotary actuators that might also fit your requirements. Here is a actuator company with a good selection of types.

If you have not already looked it over, the original Autolite manual for the Packard system can be downloaded. Other than current draw, I don't remember if there are any other specs mentioned on the original motor parameters.

HH56 wrote:
Absolutely get in touch with Mr Pushbutton for his thoughts on the subject but if you want one of his rebuilt stock Packard units, unless things have changed in the last year or two I believe he may have an arrangement with one of the vendors to handle sales. The last time I spoke with someone buying a rebuilt unit they were also quite expensive -- and much more so without an old one to return.

For my two cents, I think the idea has merit as Packard actuators do have some issues that might be able to be eliminated with something plug in but a bit more robust. If you come up with something plug in that can use stock PBs, not only could it be used with a stock Ultramatic, possibly with a slight mechanical change and a bit of different programming it might also be adaptable to those who might want to or have already converted to the GM transmissions. There has even been some thoughts of using an 80s era Rolls Royce actuator for the GM conversions.

Regarding your question on strength: the original actuator was a bit weak in one area. It was fine for changing from one gear to another 99 percent of the time but if the car was parked on an incline or hard against a curb with tire pushback, with force of the tire or the weight of the car pushing against the parking pawl, the motor often did not have enough power to pull the pawl out of the parking gear. In those situations the car was locked in park until some means was found (often a tow truck) to remove the weight from the pawl.

On the speed, I doubt if anyone has measured it precisely but from this video posted by Mr Pushbutton it appears to take 2-3 seconds.

For whatever you come up with for a drive, since you are going to use a microcontroller setup to activate it, I think it would be good to go with some kind of direct optical encoder feedback off the actuator and have the microprocessor count pulses to determine exactly how many complete or partial revs of the motor it takes to determine where to stop. After spending years working on medical equipment that relied on precision potentiometers to determine positions of various items, I will disagree with Pgh Ultramatic on the point of trying to rely on a varying analog voltage to precisely control the stop points. Granted, it might be easier and maybe less expensive but even the most precision of pots do vary slightly in repeatability. A bit of corrosion on a connection, wiper, or in the suggested push button divider circuit can also affect a voltage enough that it could change stop points enough to matter. While the Ultramatic is not nearly as critical an application, the issue was noticeable enough in a clean environment so unless you get sealed components and take extra care with connectors I would wonder how the harsh conditions -- heat, vibration, dirt, grease, moisture, etc -- in a car would contend. The downside to using digital and microcontrollers is to remember that power in cars of that era was quite dirty. There was no consideration given to surges and spikes caused by relay or switch contacts operating and motor brush noise will be a serious issue. You will need to filter the heck out of things and even then, if a long run is involved, your 3.3 volts could be seriously affected.

Packard's fingers did a good job of finding the precise place to stop and I would try to duplicate that precision as much as possible. Optical sensors positioned much like the fingers might work but they would have to be mounted on a special new support which might be hard to place and also be weather resistant.

To go along with concerns about electrical position error, I would also suggest placing the actuator at the transmission to avoid introducing any mechanical error via slop from the cable and attachment points into the mix. Since the detents are part of the valve body, unlike the manual handle where you can feel if slop has developed or if you are fully in a position or not, if the motor stops where it thinks a gear is positioned but cable or mechanical slop adds an error and the motor has stopped with the valve between detents all kinds of problems will result.

No idea which type mechanisms you are considering but there are some rotary actuators that might also fit your requirements. Here is a actuator company with a good selection of types.

If you have not already looked it over, the original Autolite manual for the Packard system can be downloaded. Other than current draw, I don't remember if there are any other specs mentioned on the original motor parameters.

HH56-I charge $650 with a good rebuildable core (physically intact, motor is not burned out) plus return shipping. If I have to supply the core it's an additional $250. To a guy with a tired Clipper that he just wants to enjoy from time to time that may seem like a lot of money. To a Caribbean owner--not so much.
I'm not getting rich off of doing this.