Packard Forum Index » V-8 (1955-56)

I don't know one way or the other about Hash getting screwed up engines. But perhaps it could make more sense if Hash deliberatly bought substandard engines from Packard for cost savings. I would not consider it ridiculous. Just unproven or lacking evidence.

After all, it's not like Packard was known to buy oil pumps from GM that were as good quality/design as they should have been. 56 rear axle shafts another example. Firestone tires on late 80's Ford explorers. That list goes on and on and on.....

Hi Ross

Sound like good functional improvements to make the Ultramatic more flexible for driving conditions today.

Once those changes prove to have no deleterious affect on long-term durability, offering a retrofit shift kit would be a good idea.

I'm sure there would be a market for them in the Packard community.

Steve

If you take a look at the article that Ross cited from the February, 1956 Service Counselor, you'll see that the modification was offered for 54th Series Gear Start and 55th Series Twin Ultramatic. Ross has extended the underlying logic to further tailoring and into the 56th Series.

Because both modifications involve only the rear upper valve body, the work can be accomplished with the trans in-car, with the pan removed. However, I don't think a packaged shift kit is necessary.

The shim for the direct shift valve piston can be fabricated locally, but the SC image isn't very clear. Perhaps Ross could indulge us with a pic of his shim, relative to the piston from a disassembled unit. However, thickness of the shim may well vary, depending on the desired feel, which would require some experimentation on the part of the owner and installer. Thankfully, the Ultramatic pans have a drain plug for capture and re-use of the fluid.

The low-high shift valve spring simply needs a bit snipped off, but perhaps Ross could provide a pic of a stock spring showing the cut point. However, we need to know the length of the stock spring, which is the same for all three years, to make sure someone hasn't already been there and done that. That is, we don't want to cut too much off that spring, which would be irreversible.

Yet, since Ross was working on a '56, I'm wondering what the difference is between the low-high shift valve piston of '56 compared to that of '54-'55. That is, the parts book shows two different numbers for that piston between '56 and '54-'55, but the spring remains the same for all three years. I wonder, then, if Packard engineers were manipulating the length of that piston to change the shift point. If so, perhaps that will affect how much needs to be trimmed off the spring for '54-'55.

Since the engines sold to American Motors had different specs from Packard or Clipper they couldn't have palmed off defective ones.

Unless someone can show me a 374 in a 56 Nash, with a couple of pistons missing.:)

Quote:

No question about that here, just some observations that different companies sought different qualities in their automatics, and hence it's subjective what is a "good" trait or a "bad" one, particularly regarding shifting. Some folks like more positive shifts, even in a luxury car.

It comes down to driver preference what would be considered "the worst" shifting characteristics. Heck, the last of the big Cadillac Brougham models locked up at about 30 mph. That was a gas mileage thing, more than likely. It sure wasn't a driveability consideration!

Some characteristics are almost always bad in the mind of almost any driver, such as shift points that rob acceleration, or those "overlapping" shifts (never experienced that) and ways to modify them out of a trans have a lot of general appeal. Good to know someone is willing to share their experiences.

So, some more tweaks for the T-U please.

I have checked 2 springs, mine, and one from pac sw, both 1-15/16ths,

I think instead of going off spring, it would be more standardized , to say leave x amount of spring sticking out end of valve body,

At this, writing, ross, said, about 1/8 inch, sticking out of valve body end, direct shift shim 1/8 inch.

thanks hh, for link,,

thanks,,ross,,,

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I have a 55 and 56 tore down and will be assembling soon for upcoming show. I have a couple NOS 55 and 56 valve bodies. When I get to the valve bodies, I can measure the pistons so see what if any variation they have.

Hope Thats right...

Will clipping the springs solve the racing between low and high shirts? My 55 400 Ultramatic is great except for that. It does not race on very moderate acceleration, but all other times it does.

Bernardi

Check in the service index under 55/56 Twin Ultramatic under the topic "Engine Flare". Several possible causes.

Mine GS will do that when the fluid is hot. When cold it doesnt. As I know I have leaky bushings and worn clutches.