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Thread: Attempting to wake up D8 2U after 30 Years

  1. #1
    Join Date
    Dec 2018
    Location
    Minnesota
    Posts
    56

    Default Attempting to wake up D8 2U after 30 Years

    I'm helping a friend get his 2U running. The pony is running well, cooling system full and not leaking, and have clean fuel to the transfer pump.

    We tried to get the main rolling over yesterday. First with pony, then pulled and pushed a bit with a 953B and then back to jogging with the pony. We got it to turn over about 3/4 of a revolution and then doesn't seem to want to budge. Don't want to damage the pony clutch, so we quit for the day. Poured oil down the exhaust stack and gonna let it sit a bit. Would like an easy way to get lube or kroil to each cylinder. Any suggestions?

    Could someone confirm that the crank pulley bolt is 2 3/4". Thinking of putting a socket and bar on it to try to jog back and forth, but dont want to buy a socket that is wrong size and it's not the easiest place to get a tape measure in to check.

    Pulled the cover on fw and only see a pointer and no way to bar. Is there any other place to bar these over??

  2. #2
    Join Date
    Apr 2012
    Location
    Moose Lake, MN, USA
    Posts
    3,465

    Default

    Quote Originally Posted by Oldcarman View Post
    I'm helping a friend get his 2U running. The pony is running well, cooling system full and not leaking, and have clean fuel to the transfer pump.

    We tried to get the main rolling over yesterday. First with pony, then pulled and pushed a bit with a 953B and then back to jogging with the pony. We got it to turn over about 3/4 of a revolution and then doesn't seem to want to budge. Don't want to damage the pony clutch, so we quit for the day. Poured oil down the exhaust stack and gonna let it sit a bit. Would like an easy way to get lube or kroil to each cylinder. Any suggestions?

    Could someone confirm that the crank pulley bolt is 2 3/4". Thinking of putting a socket and bar on it to try to jog back and forth, but dont want to buy a socket that is wrong size and it's not the easiest place to get a tape measure in to check.

    Pulled the cover on fw and only see a pointer and no way to bar. Is there any other place to bar these over??
    Is the decompression lever working? I, sure you know his but it should be in the start position. The pony transmission is a two speed on the 2U. Is it in the lower gear? Does it go 3/4 revolution in either direction? If so it could be a stuck valve you are pushing against. I doubt that oil in the stack will help as the pistons are moving. Pulling the valve cover and insuring all the valves are free by pushing them down with a bar may be a cost saving measure. It sounds like the cam is coming up against a stuck valve. Forcing it will probably break or bend something. Is the transmission in neutral and not impeding the engine turning? There could easily be 3/4 turn of engine revolution slack in the gears. On my dry clutch D2 I have used a 5 ft. crow bar stuck in between the thermoid couplings on the clutch to turn the main over in either direction with the compression release on start with relative ease. You will have to remove the front floor cover for access. Not sure if this is the same on the later wet clutch machines. Good luck and keep us posted.
    1937 Cat #11 tandem auto patrol,diesel, w/plow and wing, 6K506SP, 1937 RD 4 Ag Crawler RD5356, 1939 Cat 22 2F5429, 1952 Model 212 Grader 9T03427, 1953 2U D8 Dozer 2U20751, 1961 922A Rubber Tired Loader, 59A812, LeTouneau LS Cable Scraper, Cat/Lincoln 600 AMP Dual Welder, DW-21 Cat Scraper, DW-10 dump wagon/water wagon

  3. #3
    Join Date
    Nov 2006
    Location
    Corralitos, Ca.
    Posts
    14,524

    Default

    Go back to the timing cover for the flywheel. Remove the pointer and you have access to use a pry bar engaging the ring gear teeth. It's a slow process but provides the rocking action to get things free if it isn't seriously locked up.

  4. #4
    Join Date
    Feb 2018
    Location
    Missoula Mt
    Posts
    219

    Rip

    You better pull the heads, the damage you WILL do to the bore and pistons if you do break it loose will not be worth the excitement of a few secs of smoke . It is stuck for a reason and will not free up and be all better if you make it start!!....WA7OPY

  5. #5
    Join Date
    Dec 2018
    Location
    Minnesota
    Posts
    56

    Default

    OM, thanks again for a good tip on the barring point. The compression was released, pony in low gear.

    Will see what happens when we carefully go back and forth baring it. The fact that the pony would move the crankshaft suggests to me that it's not a total pile of rust inside, but I will let the owner make the call on how we proceed.

    Thanks for the comments!

  6. #6
    Join Date
    Nov 2006
    Location
    Gold Coast, Queensland, Australia
    Posts
    4,685

    Default Stuck?????

    Hi, oldcarman.
    It you have got the main engine to turn 3/4 of a turn, I would doubt that any of the pistons are stuck. I suspect that there is some other cause than stuck pistons. Old Iron Habit's thought of a stuck valve could be a possibility.

    If it has been sitting out under God's great blue canopy for 30 years, there is also the possibility that it has water in at least one cylinder and you are coming up against a 'hydraulic lock'. To check this, remove the rocker covers and push each exhaust valve down while holding pressure against the lock with a bar through the timing inspection cover - remove the pointer as Old Magnet suggested.(I hate to have to say this about God's great blue canopy but it does LEAK, mostly when the blue turns to dark grey.)


    You could also remove the crankcase side covers to have a look at the bottom end.

    Just my 0.02.
    You have a wonderful day. Best wishes.

    Deas Plant.

  7. #7
    Join Date
    Nov 2006
    Location
    Santa Cruz,CA
    Posts
    224

    Default Could it be mice ??

    I've had two tractors whose engines would rotate both directions, but wouldn't do a complete revolution. One was a U series D2, and the other a Massey Ferguson with a Perkins diesel. In both cases mice had entered via the exhaust pipe and deposited enough nuts & seeds through open valves to get crushed by the piston against the head and prevent complete rotation.

    Pulled the head, cleaned her out , and all was good. Now every exhaust pipe is covered with a can.

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