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Seized pup/pony motor

Discussion in 'Track Loaders' started by Brent Irwin, Sep 13, 2017.

  1. Brent Irwin

    Brent Irwin Member

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    Sep 7, 2017
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    6
    Location:
    Thunder Bay Ontario
    As I posted in my original thread, my pony motor has seized. Just wondering if anyone has any tricks to help unseize the motor without taking the whole thing out? An old mechanic told me to put Coca Cola in it and leave it for a week. That seems like and absolute last resort. If anyone has any tricks im all ears.
    Thanks for reading
     
  2. DMiller

    DMiller Senior Member

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    We used to use acetone and rislone oil additive on old stuck engines. One frees the rust the other works on carbon
     
  3. TomA

    TomA Well-Known Member

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    Mariposa, CA
    Kroil is good, expensive though. Is it a vertical or horizontal pony motor?
     
  4. Hobbytime

    Hobbytime Senior Member

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  5. old-iron-habit

    old-iron-habit Senior Member

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    Retired Cons't. Supt./Hospitals
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    Pull the head or heads based if it is vertical or horizontal pistons and see if the valves are stuck. They are good at sticking especially on the horizontal ponys like the D2, D4, and D6. If so they can often be freed up. The head gaskets are reusable. I would pull the head first in any event and take a look.
     
  6. Randy88

    Randy88 Senior Member

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    If its at least a twin cylinder and not a single cylinder, around here on old tractors, they take the valve cover off and see what cylinder has the valves closed and remove that spark plug, fit a hydraulic adapter to the spark plug hole, hook the hose to a tractor hydraulics and use hydraulics to bust them loose, slickest thing I've ever seen done, and if it won't go, chances are, it wasn't rebuildable anyhow.

    I've been told, on a single cylinder engine, you remove the rockers assembly so the valves go shut, then use hydraulics to bust the cylinder loose.

    This only works as long as the piston is not at the bottom dead center, anywhere else in the stroke it will work, filling the bore with hydraulic oil and using pressure to shove the piston down enough to crack it loose.

    As they say, you asked for idea's, might be a bit radical, but there's a place around here that buys old tractors, and does this by the hundreds, maybe even thousands of engines to break them loose over the years, if they blow the engine wasn't worth fixing anyhow. Just a suggestion and off the wall method not mentioned.
     
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  7. kshansen

    kshansen Senior Member

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    Retired Mechanic in Stone Quarry
    Location:
    Central New York, USA
    I like the idea of the hydraulics of another machine to free up an engine!

    Wish I had come up with that idea many years back. Had a Mack truck at one of our plants that rusted up parked over winter. Tried pushing it in gear and just slipped clutch. Out of desperation I came up with the idea of using the air powered grease pump.

    Found out which cylinder had valves closed and the took junk injector and modified it to take grease fitting. Pumped grease in till engine turned, Then moved to second cylinder and repeated.

    Now for the fun part! Removed injectors and had loader push truck and let out clutch! Shot a stream of grease at least twenty feet in the air landing on top of shop! Put injectors back in and hit starter. Cranked right up but sure did smoke a bit!

    Engine ran okay after that but always did use a little more oil than normal, other choice was a tear down for an in-frame overhaul.
     
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  8. old-iron-habit

    old-iron-habit Senior Member

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    All Cat pony motors are 2 cylinders. Horizontal opposed twins are mounted across the back of the main on the D2, D4 and D6. Vertical twins are mounted on the side of the block on the rest including up thru the D9s. Valve sticking from non use is very common on the horizontal opposed twins. While the heads are off clean the crap out of the lower water passages that are probably plugged also.
     
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  9. 56wrench

    56wrench Well-Known Member

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    alberta
    Had mice get into the pup engine exhaust of my cat#12 years back and enough seeds dribbled through the valve into the cyl causing it to lock up at the end of the stoke. Checked the spark plugs and figured out which side(blew air in spark plug hole-seeds blew out),removed head, vacuumed out cyl and valve port, reused gasket and bolted it back together. Still working. Blew seeds out the exhaust for a couple minutes after it fired up
     
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  10. DMiller

    DMiller Senior Member

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    Had to pull a locked up pony on a D8 years ago, was closed up and no way for moisture but seems was there as plugs were rusty. Owner opted to overhaul rather than patch or convert to electric and when opened the rats nest the mice left was unexpected. Suspicion was mouse urine was the moisture we were detecting as well the moisture from the nest and food materials dragged in thru the intake, a hole in a boot was found as the access hole. Honed, set of rings and I believe less than $100 worth of gaskets back in business.
     
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  11. 56wrench

    56wrench Well-Known Member

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    alberta
    Damn mice sure cause their share of grief (corrosion) and chewing wiring harnesses usually where its hard to get at. lol
     
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  12. old-iron-habit

    old-iron-habit Senior Member

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    If you get the pony unstuck, do not worry about low compression. They will run and start the main with as little as 30 PSI of compression. Fire it up and see what it will do.
     
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