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Thread: Oldsmobile motor position problem

  1. #1
    Join Date
    Aug 2008
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    1,189

    Oldsmobile motor position problem

    I have the motor in my '73 H/O installed, with a TH200-4R transmission. From what I am seeing, the motor mounts do not differ from big-small block. The trans mount is the same height as well. I see no evidence of any frame damage, and my crossmember measures the same as others that I have.

    My problem is that the motor noses down at the front. To keep the fan from hitting the shroud, I need to use a 1" spacer to hold the shroud lower. this in turn keeps the lower bolts from aligning. My thoughts are that the motor may be sitting low, or the trans may be sitting high. Has anyone ever seen this?

    Also, does the OD trans have the same spline count as the driveshaft piece from the TH 400? Would the TH400 spline physically fit into the 220-4r? I'm not sure if I have the driveshaft from the car, or maybe the one from a TH 350. I thought I got the yoke with the car, but it does not look like there is a new U joint at the front.

  2. #2
    Join Date
    Mar 2007
    Posts
    215
    It sounds like the trans mount is too high.
    Alan
    76 Cutlass Supreme Braugham (3)
    73 Cutlass Supreme
    66 Olds Ninety Eight LS (expired)
    78 Cadillac Seville (350 Olds engine)
    Several Caddys and a 76 Camaro and
    70 Impala Convertible

  3. #3
    Join Date
    May 2010
    Location
    Northern NJ
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    26
    I just replaced the clutch and fan on my 73 H/O - same problem.. fan rubbing at the bottom of the shroud. Shimming the top worked for me but I plan on replacing motor and trans mounts next.

  4. #4
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    Sep 2017
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    San Jose, CA
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    I have seen this issue before and believe it or not I think it has to do with the body mounts. As they age they sink a little and deteriorate just enough to throw the body out of alignment. I don't know if replacing the engine and trans mount will fix the issue, but I suspect not.
    All engine mounts are the same for Olds engines in these cars. The lower parts of the blocks are externally identical and the crankshaft interline is the same. As for the yoke.....the 200-4R uses the same mount location as the TH400, but the yoke of a TH350. The length should be the same as a TH350 as well so if you get a driveshaft for a TH350 car you should be good to go.

  5. #5
    Join Date
    Jan 2008
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    McHenry County, IL
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    1,150
    I have this same issue with my 74 Hurst. I've even replaced the motor mounts with no luck. I never checked the trans mount. The exhaust headers swing down lower than my 75 442, same motor/trans/headers too. The fan shroud also has a 1" spacer pushing it down further. I looked at the core support and I think someone put the wrong bushings on the core support pushing it up too much so it hits on the bottom.

    It makes zero sense that the body bushings have anything to do with it. The motor/trans is attached to the frame. Also the front core support would have to "rise" to make you have to use a 1" spacer to push it down, so that makes no sense either.
    Nick
    H/OCA #1688
    OCA #043109
    74 H/O W30 black with white top
    74 H/O W30 white with black top
    75 442 455/400 crimson
    75 442 350/350 crimson
    75 442 350/350 cranberry

  6. #6
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    Aug 2008
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    Update. I made my own trans support mount in the thinnest way possible to see what happens. It pulled the motors nose up a bit, but not significantly. I just checked my door lines and the top of the gap is about 1/64th wider than at the bottom. Can't give specifics as my micrometer battery died.

  7. #7
    Join Date
    Mar 2007
    Location
    Pontiac, MI
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    2,311
    I've never swapped a big block in an Olds, but I thought the metal pads that bolt to the frame cross member are different?
    Todd

    '76 H/O {Concept}

  8. #8
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    Sep 2017
    Location
    San Jose, CA
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    Quote Originally Posted by ragz442 View Post
    I've never swapped a big block in an Olds, but I thought the metal pads that bolt to the frame cross member are different?
    You can use any modern Olds engine (64-90) on the same engine mounts. The crank center-lines are all in the same spot relative the the engine mounts. The only time there were different mounts were 69-72 in the A body cars. After that and before that they all used the same mounts.
    Last edited by svnt442; 01-01-2018 at 12:21 PM.

  9. #9
    Join Date
    Jan 2008
    Location
    Vancouver BC Canada
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    341
    Motor mounts are the same for SBO and BBO. The 1968- 1972 SBO used frame mount#2261. in 1969-1972 BBO use #2328. In 1973 and up used #2328 for SBO and BBO. I am not really that smart i looked it up on another web site!
    Mike

  10. #10
    Join Date
    Mar 2007
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    Pontiac, MI
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    Good to know, I remember reading of issues with the frame mounts with engine swaps years ago on ROP, obviously pre 73. If there are shims on the core support bushings you could try removing them.
    Todd

    '76 H/O {Concept}

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