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Projects Mild custom '51 Pontiac Chieftain

Discussion in 'Traditional Customs' started by PhilA, Nov 4, 2019.

  1. PhilA
    Joined: Sep 6, 2018
    Posts: 1,814

    PhilA
    ALLIANCE MEMBER

    That's what the one I'm looking at is, custom alloy.
    They just charge a fair bit. Any one off alloy welding here seems to be rather expensive.
    At least I know this one has been measured and will fit; they've even got a photo of it mounted in a Pontiac with an I8.
     
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  2. v8flat44
    Joined: Nov 13, 2017
    Posts: 1,134

    v8flat44

    Well, "dog on it", or 2 dogs..... Phil; hope you had a happy Thanksgiving any who. You will overcome; you always have :)
     
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  3. Look around really good. The Pontiac radiators are difficult to find.
    Many say the 49-52 Chevys work. And they don't. Too short and too wide with brackets. 48-52 Chevy trucks are a little closer to core size only do not have the additional heater port.
     
  4. Bbdakota
    Joined: Oct 23, 2019
    Posts: 76

    Bbdakota
    Member

    If the exact fit aluminum radiator is too pricey, you could search for one by size and inlet/outlet, then modify as needed for mounting. I've taken this route a couple times with good results (mainly because a replacement wasn't available) but I have a TIG outfit. If you decide to go this route and don't know anyone with a TIG outfit close by, I'm about 2 hours from you. Hit me up.
     
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  5. PhilA
    Joined: Sep 6, 2018
    Posts: 1,814

    PhilA
    ALLIANCE MEMBER

    I have a lift tig capable machine but no gun; nor do I have the skill to weld aluminum.

    I can pick up a Shanghai Speed Shop rad for a Chevy, which is about 7" shorter, and has the outlets in the right place but the wrong size and direction.
    The pump has no inlet for the heater return, so that gies straight to the radiator lower tank.
     
  6. PhilA
    Joined: Sep 6, 2018
    Posts: 1,814

    PhilA
    ALLIANCE MEMBER

    Courtesy of our very own @bchctybob I have a replacement Hydra-Matic valve block... From a Cadillac. Cadillac. Mm. Caddy goodness.

    20221126_123329.jpg
    As unboxed. It's got grimy old Type A fluid congealed everywhere. Doesn't look like it's ever been taken apart- further disassembly and diagnosis may prove that false but either way it looks pretty good so far.

    20221126_123845.jpg
    First things, pull the gear selector quadrant up out of the way, off the manual valve. Then, undo the 3 screws holding the quadrant detent plunger/double transition valve vent.

    20221126_124404.jpg
    Front servo exhaust valve comes off the other side, then the 3 screws undo and the two halves separate. The plate is complicated but only fits one way; still, try to keep it the same way up.

    20221126_124735.jpg
    On the lower half, the governor pressure valve cap comes off (top right) and the shift speed modulator block comes off (top left)- caution undoing that, it is spring loaded from inside.

    That's enough for tonight, all the valves are thoroughly gummed up with congealed old fluid, so when the weather is better tomorrow will be getting a warm gasoline bath in the ultrasound machine outside.

    Phil
     
    Last edited: Nov 26, 2022
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  7. BJR
    Joined: Mar 11, 2005
    Posts: 8,000

    BJR
    Member

    If the radiator doesn't have a return line in the lower tank for the heater, you can put a T in the lower hose for the heater return. I did that for my 472 Cadillac in my 49 Buick.
     
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  8. PhilA
    Joined: Sep 6, 2018
    Posts: 1,814

    PhilA
    ALLIANCE MEMBER

    Had a thought and bought a can of Berryman Chem Dip, apparently from 2018... Unless they didn't change their packaging (would hardly think they'd miss their centenary).

    Phil
     
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  9. PhilA
    Joined: Sep 6, 2018
    Posts: 1,814

    PhilA
    ALLIANCE MEMBER

    Cleaned the valve block. There was not one single shuttle that was free to move- old hydraulic fluid all congealed with time.
    20221127_140129.jpg
    Cleaned down all the ancillary parts. I was wrong, somebody had been inside this before, because one of the valves was installed backwards. It was all jammed up and would have only worked in 1st and 3rd gears- likely why it was parked.
    This is the block which has throttle valve pressure on- the shuttles push against the governor pressure, making the gearshifts occur at a higher road speed the more you press on the gas pedal.
    20221127_131319.jpg
    This is the way round the valves go in the respective bores. Note the top and bottom ones can be swapped which is wrong- the bottom one has a flat and a point, the top two flats.
    20221127_145718.jpg
    Once you remove the throttle valve, this pin needs to be pulled out. The 4-3 shuttle has a small hole in the end, push a screwdriver into it and then the shuttle can be removed. It has to be maneuvered through a gallery that it falls out of line and easily gets jammed.
    20221127_145656.jpg
    Gently pull it out- it may need a push from the other side.
    20221127_145412.jpg
    It's the last thing out and the first thing back in. Refitting is reverse of removal.
    20221127_145743.jpg
    Fitted back in, you can see the pin in place.

    Continued...
     
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  10. PhilA
    Joined: Sep 6, 2018
    Posts: 1,814

    PhilA
    ALLIANCE MEMBER

    The double-transition valve has a spring behind it, that fits back in here. This valve is responsible for the rapid 2-3 gearchange where the transmission goes from clutch, band to band, clutch. If it gets slow or jams up it is responsible for the traditional Hydra-Matic harsh shift.
    20221127_145811.jpg
    Next up, the compensator valve. Again, spring loaded.
    20221127_145857.jpg
    This one adds additional pressure behind the servos to add additional clamping force to prevent the transmission slipping when you've got your foot in it. On the 8 cylinder versions (like this one) there's a second valve on the pressure regulator which reduces the system bleed pressure to about 60psi (down from the normal 80-85) to prevent the lowest clamping force from engaging too hard- the additional clutch material added caused snatchy shifts at light throttle.
    20221127_150010.jpg
    Throttle valve/4-3 downshift shuttle. Free floats between the 4-3 blocker plug and the throttle valve.
    20221127_150025.jpg
    Throttle valve, with spring that needs persuasion to sit in both cups.

    Continued...
     
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  11. PhilA
    Joined: Sep 6, 2018
    Posts: 1,814

    PhilA
    ALLIANCE MEMBER

    The smallest shuttle, but still important - throttle valve plug.
    20221127_150244.jpg
    That should freely push from the other side and back, moving all three shuttles in the tube.
    20221127_150707.jpg
    Manual valve needs to be put in next, after the front servo dump end block.
    20221127_151016.jpg
    Throttle valve lever needs to be put down, then the detent spring block needs to be fitted, then the manual valve can be engaged with the quadrant as shown.
    20221126_124735.jpg
    I forgot to take a picture, but the lower block needs the springs fitting as shown, the outer two shuttles are interchangeable, the center not. The governor pistons are all interchangeable, find the best fit for each bore- they should fall out under their own weight.
    20221127_144435.jpg
    Both end caps on, and the plate is this way up.
    20221127_151535.jpg
    All back together, ready to fit.
     
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  12. Johnboy34
    Joined: Jul 12, 2011
    Posts: 1,528

    Johnboy34
    Member
    from Seattle,Wa

    Does this one have less ware than yours? Valves move without sticking?
     
  13. PhilA
    Joined: Sep 6, 2018
    Posts: 1,814

    PhilA
    ALLIANCE MEMBER

    It's got some miles on it but seemingly fewer than mine has. It does move freely, the main changeover valves (that basically do all the work) are all lot more smooth to operate than mine.

    All that's left now is to fit it and see.
     
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  14. TrailerTrashToo
    Joined: Jun 20, 2018
    Posts: 1,205

    TrailerTrashToo
    Member

    Fingers crossed...
     
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  15. FishFry
    Joined: Oct 27, 2022
    Posts: 237

    FishFry
    Member


    It's so much fun to read, cause it's so well written by Phil - at least for me, I really enjoy it.

    Frank
     
  16. Great tech again Phil! Always impressed how you have such a grasp on the tech nomenclature. Hope it solves the shifting issue for you.
     
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  17. PhilA
    Joined: Sep 6, 2018
    Posts: 1,814

    PhilA
    ALLIANCE MEMBER

    Thanks, folks.
    I got so involved with cleanup and reassembly (a lot of wiggling shuttles into bores and seeing how they slide under their own weight) of the main valve body I forgot to take photos! Time was getting on and a bunch of wasps and hornets were taking an interest in my presence- the hornets would only go if I managed to physically swat them away. Persistent things!
     
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  18. Johnboy34
    Joined: Jul 12, 2011
    Posts: 1,528

    Johnboy34
    Member
    from Seattle,Wa

    Hornets & wasps at the end if November? Up here those guys have been napping for a awhile now.
     
  19. PhilA
    Joined: Sep 6, 2018
    Posts: 1,814

    PhilA
    ALLIANCE MEMBER

    Here, they rarely sleep. We had a cooler snap, a week of weather in the 50's and 60's; one stormy hot day and one following humid in the 70's had them all wake up.
     
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  20. Hornets and Wasps????? So this is a thread about Hudsons? I'm confused...
     
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  21. PhilA
    Joined: Sep 6, 2018
    Posts: 1,814

    PhilA
    ALLIANCE MEMBER

    New valve block is in.

    It's still getting hung up occasionally. So, that's great fun.

    However, one thing that is definitely better, in 4th it no longer chatters. I think it was partially engaging another gear at the same time.

    Further investigation follows.

    Phil
     
  22. PhilA
    Joined: Sep 6, 2018
    Posts: 1,814

    PhilA
    ALLIANCE MEMBER

    Thinking about it, 3-4 gets hung up sometimes also- that leaves it down to one thing.

    The front servo is getting hung up.

    Edit:
    Bonus, it doesn't engage the parking pawl in reverse now, so that's two issues solved.
    If I stamp on the gas pedal, that adds pressure to the compensator circuit, and that'll now often make it change to second.

    So, that's what it's gotta be- the front servo is getting physically stuck. I think I can drop that out without having to remove the transmission.
     
    Last edited: Nov 28, 2022
  23. PhilA
    Joined: Sep 6, 2018
    Posts: 1,814

    PhilA
    ALLIANCE MEMBER

    No. Can't be.

    Still looking, going through the manual.
     
  24. PhilA
    Joined: Sep 6, 2018
    Posts: 1,814

    PhilA
    ALLIANCE MEMBER

    Only thing I can think of with what it does is the governor is sticking when it gets hot.



    Cold, it shifts really well.
     
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  25. Johnboy34
    Joined: Jul 12, 2011
    Posts: 1,528

    Johnboy34
    Member
    from Seattle,Wa

    Just thinking out loud here, isn't the band applied with a spring? The servo releases it? Since you said "stepping on the throttle", could the throttle pressure adjustment make up that difference?
     
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  26. PhilA
    Joined: Sep 6, 2018
    Posts: 1,814

    PhilA
    ALLIANCE MEMBER

    The front servo is held off with a spring, but is activated in both directions by hydraulic pressure, both on and off.

    The rear band servo is held on with a spring but again operated in both directions by hydraulic pressure.

    In both instances, the springs merely assist and/or apply the rear band with the engine off.

    Edit: Further to that, I didn't answer your question, sorry.
    The compensator pressure which is added by stepping on the throttle does two things- firstly it is applied in progressive amount to assist in forcing the bands to engage. Secondly, it boosts the overall main line pressure from 60 to about 80-85 psi in the early stages of the throttle being opened, so that will vary the force on the parts too.

    However, I looked at the way the 1-2 change operates. 1st is engaged when Drive is selected, by applying pressure to the servo only, engaging it and clamping the band on (and clutch off so the sun can rotate and perform ratio reduction).
    When the 1-2 shuttle moves over, that is a single line of pressure to both the servo and the clutch.
    The clutch will then engage, and a bit of physics is used for the servo- the other side of the piston is larger so the servo is forced disengaged, loosening the band and then the sun turns at the same speed as the input shaft.

    If the servo was sticking, the clutch and the band would both be engaged and the gearbox would lock up solid (two gears at once).
    It's definitely not doing that, so all I can surmise is that is not getting the instruction to change- either there's inadequate pressure to push the valve over against the spring or this is getting stuck in exactly the same way (not so likely).
    Thus, my attention turns to the governor. Which was new 5000 miles ago. I guess new does not equate non-problematic...
     
    Last edited: Nov 29, 2022
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  27. PhilA
    Joined: Sep 6, 2018
    Posts: 1,814

    PhilA
    ALLIANCE MEMBER

    On a complete tangent, it's time to pull the radio out and find out why it sounds like junk.

    Could be the speaker cone has gone might be a bad contact. Let's find out.
     
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  28. PhilA
    Joined: Sep 6, 2018
    Posts: 1,814

    PhilA
    ALLIANCE MEMBER

    Pulled the radio out because I was getting antsy about it.
    20221130_194018.jpg
    Took one look and figured the problem.
    20221130_194227.jpg
    Loudspeaker selection switch- crusty. Cleaned that up, now it's playing great.
    20221130_195929.jpg

    Phil
     
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  29. bchctybob
    Joined: Sep 18, 2011
    Posts: 4,280

    bchctybob
    ALLIANCE MEMBER

    Loudspeaker selection switch? Multiple speakers in 1951?
     
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  30. Johnboy34
    Joined: Jul 12, 2011
    Posts: 1,528

    Johnboy34
    Member
    from Seattle,Wa

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