This is an interesting thread I copied over from the Yahoo group about Flight Pitch (Triple Turbine) versus Variable Pitch (Twin Turbine) Dynaflows:
I thought I'd post this question to the group:
I have a '58 Limited that I'm working on, which should have come
standard from the factory with a Flight Pitch Dynaflow
transmission. However, at some time in it's history, the engine and
transmission were swapped out for a 1960 401 engine and trans.
The existing trans works fine and only leaks a little (who's
doesn't). I have a Flight Pitch from a '58 Roadmaster parts car,
but don't know what state it's in. I don't have the original 364
engine though.
If I do try to put the Flight Pitch in, what modifications would I
need to do to make it fit to the 1960 401 engine? Would it bolt
right on? Is the torque tube the same length? It looks like I'd
have to change the shift linkage, maybe the thrust pads (?), and
gear shift pattern plastic. What else needs to change? Would I
have to get a 364 engine? And finally, is it worth it to make the
change? I understand that the Flight Pitch has problems and could
be expensive to repair. Would it be worth it to make the swap?
Thanks for your help
Bill
Hi Bill,This is only my opinion based on what I know
and have done.First,How important is it to you to have
an original drivetrain?If you are just having fun and
it all runs and shifts good,fine.Leave it that way.
The flightpitch was trouble prone and if it is from a
parts car it would need checked out before you go to
the trouble of a changeover.I got my Limited with its
original flight pitch in it,but it started
malfunctioning in reverse and sluggish in forward.I
have a variable pitch in my 58 special and think it is
great!I will put one of those in my Limited when I get
to.I believe some parts for flight pitch are nearly
impossible to get.(clutch discs)Bill Shoening ran an
article on rebuilding one a few years ago.I'm sure
others here have also.I have rebuilt a variable pitch
and had no problem with parts.
The flight pitch uses the bolt pattern forward of the
ones your current variable pitch is bolted to.The
linkage is different also,and mounts and
crossmember.The lines to the radiator are different
and a bigger size.I can't think of any other items at
the moment.I hope you would have those if you go with
the change.
There was a seperate manual aside from the regular
shop manual in 58 for the flight pitch.It has also
been said to use a 59 shop manual to rebuild
one.Corrections were made.
I don't know if a 401 will fit it.Probably,but again
someone else will hopefully give some insight.
I hope this helps.....Lee
Bill,I don't think I was clear on where the Flight
pitch crossmember goes.Look under your car where your
variable pitch cross member is.Follow along the frame
a bit towards the front and you will see another set
of holes for mounting the flight pitch
crossmember.This is what makes up the difference in
the torque tube length.
If you have shims between the crossmember and
frame(variable pitch) in your car now,you may need
them again if you were to put in the flight pitch
cross member.This is very important to take out any
free play....Lee
The flight pitch is supposed to be a smoother shifting transmission and it works fine when properly rebuilt and adjusted. Many people in 1958 and 1959 complained that it had a lot of slippage (engine revs up without corresponding response from transmission). I have driven a car with it installed and it seemed fine to me.
You would have to change the transmission cross member and mounts. This transmission is extremely hard to find parts for. There is someone in San Antonio and someone on the west coast who rebuilds them - $1000 to $1500 last time I checked. Are you in the Buick Club of America? Check their tech support list in the monthly magazine. Don Duddles in San Antonio is listed there - he works on them. Wayne Medlin is listed also and he knows how to contact the guy in California. I have heard two different answers on the torque tube - some say it needs to be changed, others say it is the same length - maybe someone from the group can answer this. Bill Scheoning wrote an article about rebuilding the flight pitch for the Bugle - BCA's magazine. He is also a member of this group so maybe he will respond to this discussion.
My Limited was converted to a variable pitch sometime ago. It performs fine and can spin the tires in low gear. I have a flight pitch and cross member, but I don't think I will replace the one in my car anytime soon due to the difficulty in finding parts. No one in my area can work on them, so I would have to remove it and ship it off anytime something went wrong. I plan to keep the parts in case I change my mind. I think the 401 mount up is the same, but I won't swear to it. My flight pitch came out of a Super (original to the car) and was mated to an engine that was a replacement pulled from a 1960 Special.
David
Hi All,
Just a few comments about the Flite Pitch. As was noted I wrote several
articles on this transmission for the Buick Bugle. I have overhauled
several and have one with 200,000 miles and still is fine.
First: This transmission must be overhauled using all the changes that
came out over the year. These changes correct the major problems with
it. If you can find a 59 service manual it has all the changes in it.
After the over haul and it is done correctly, it will out preform any
other Dynaflow. Parts are hard to find and in the messages Lemar Wilkins
was mentioned. He also knows these transmission and does a very
excellent job overhauling them. If any of you can find the Bugle
article I did, you will find some of the history and suggestion to keep
it running.
Second: The oils. This is a new problem and may cause ware and strange
behavior. The new Dexron III had many of the additive packages removed
that help on heat buildup in High contact areas. As the the oils
"IMPROVE""" this will get worse. I have switched the oil to the type
FA. For now this still have some of the additives that will help. So
those of you who are having some strange problems might consider making
this change.
Third: As some of you have noted to change from a Flite Pitch to a
variable Pitch or vis versa is a big deal. There are lot of changes
that must be made. I mentioned many of these in the articles. If you
want to have your big series Buicks from 59 to be correct they must have
the Flite Pitch. I have searched long a hard to find any official Buick
data that tells the dealers to change from the Flite Pitch. If any of
you can find official data I would like to have a copy.
Hope this helps
Bill Schoening
Bill's article on the Flight Pitch is in the April 2003 Buick Bugle.
This article gives background and history on the transmission and
discusses the transmission fluids. I do not have the May 2003 Bugle,
so I don't know if there is a part 2 in the May issue.
David
Thanks you guys!..you are fountains of knowledge on our beloved 1958
Buicks!
I have a RoadMaster "75" 4 dr HDTP with 38,000 original miles and often
wonder " What will I do when my Flight Pitch goes belly up?!"
I seem to remember that the crossmembers, engine, and trans mounts were
different from
DynaFlow cars.....
Also, the stator linkage from the throttle linkage was unique to the
Flight Pitch...I think...right?
Has anyone done a conversion to an open drive line on one of these
cars? Maybe with a
Turbo 400 mated to a 364...?
Just curious.
Mike
Hi Mike,I am pretty sure the stator linkage is
different also.I pulled the Flight pitch out of my
Limited back in 1999.All the parts associated are in a
box with the trans. in a corner of the garage.maybe
someday I will take it apart just to see what went
wrong in it.
I put the Variable pitch from a Super I have in the
Limited for awhile and drove it. I didn't seal the
torque tube correctly and it leaked alot!
Now I am fixing up the Super and have since returned
the variable pitch to it.(Sealed correctly this time)
I may sell the Limited(4dr htp,all black) in the near
future.It was also a former air ride car.
I have a neighbor down the street who converted a 1950
Buick from torque tube and straight eight to a
nailhead and open driveline using a Pontiac rear
end.I'm not sure what trans. he used.He said it was
some work,but worth it.I'm sure with an adapter a
turbo 400 would be excellant.
Due to a herniated disc in my back,I don't see me
doing any conversions.I am mostly a purist anyway.I
drive a pink/white 58 Special with 26,000 original
miles and the Variable pitch takes off very fast with
a well tuned nailhead.
Lee
Hello Friends:
May I offer my experience to the Flight-Pitch/ Twin-Turbine question. I own two Limiteds with Flight-Pitch transmissions. I have had both transmissions rebuilt in southern California by Lamar Wilkins, a superb technician. He even delivered and installed one of these transmissions to my home here in Florida. Any parts unavailable, he makes himself. After years of research on the question at hand, may I suggest that the Twin-Turbine is a far better design. Although Buick continued to produce the Flight-Pitch after 1959 for other divisions of General Motors, they did not use the Flight Pitch in their newer Buicks. Due to the engineering of the Flight-Pitch transmission, it cannot fully use the "high" gear ratio until about 80MPH. This is explained in Buick's service manual for the Flight-Pitch. If the Variable Pitch is working properly it will be far more economical and far less troublesome. The Variable-Pitch torque convertor "locks" far tighter to the engine once up to about 40 MPH. Even after rebuilding, one of my Flight-Pitch transmissions will not engage "REVERSE" without special prompting. I did recently drive a Variable-Pitch that worked far superior to either of my Flight-Pitch transmissions. I have kept the original factory design here and have gained little for all the effort and expense. Once again, it is my suggestion to keep the Variable-Pitch transmissions, rebuild them well, and enjoy your wonderful classic Buicks.
Happy driving,
Tom