Page 1 of 2 1 2 LastLast
Results 1 to 10 of 19

Thread: Cucv engine turns smoothly almost a full rotation by hand then comes to a complete st

  1. #1
    Private
    Join Date
    Aug 2017
    Location
    Tampa,Fl
    Posts
    21
    Thanks
    6
    Thanked 9 Times in 6 Posts

    Default Cucv engine turns smoothly almost a full rotation by hand then comes to a complete st

    Hey guys, so I got my injector pump and such and so the m1028 has been sitting for 10 years and it ran perfectly even though the injector pump croaked. But me and my dad were getting ready to start installing the injector pump and we heard you had to time it by turning the crank with a bar and it was turning so smoothly and when it was half way throght a full rotation and it stopped like it was hitting a brick wall in the same spot it was in, we opened the ports where the glow plugs go and there was no water in the cylinders, what do you guys think it is? Rust on a little bit of the cylinder wall? Pitting? And have any of you had this happen and if you have, how did you fix it? Dad sprayed wd in the cylinders and it does the same thing.
    Thanks

  2. #2
    4 Star General cucvrus's Avatar
    Join Date
    Dec 2012
    Location
    Jonestown Pennsylvania
    Posts
    7,642
    Thanks
    2,485
    Thanked 5,993 Times in 3,180 Posts

    Default

    Could be a valve stuck. Have you tried using the starter? May help get it past that point. May not but worth a try. WD 40 will only get on the intake valves if you put it down the intake. While you have the intake off spray oil down the EGR port in center of heads. Report back. Good Luck.
    To argue with a person who has renounced the use of reason is like administering medicine to the dead. Thomas Paine: Founding Father Quote.

  3. #3
    4 Star General /Moderator doghead's Avatar
    Join Date
    Jan 2006
    Location
    NY
    MVPA
    8675309
    Posts
    25,945
    Thanks
    2,515
    Thanked 13,771 Times in 5,959 Posts

    Default

    Any chance you dropped a bolt when you removed the IP?
    M817, M818, M819, M35A2 w/w, M35A2, M109, M105, M116A2, M101A2, Pioneer tool trailer, MEP-002, MEP-017A, 5ton winch shear pins, Oral-B toothbrush

    Ah Beefco Industries Northeast marketing associate

    Don't judge a fish by its ability to climb a tree

    https://www.youtube.com/watch?time_continue=12&v=T6BTcEwtmZo


  4. The Following User Says Thank You to doghead For This Useful Post:

    TGP (IL) (06-30-2019)

  5. #4
    Super Moderator gringeltaube's Avatar
    Join Date
    May 2005
    Location
    Montevideo/Uruguay
    Posts
    5,708
    Thanks
    1,291
    Thanked 3,088 Times in 1,523 Posts

    Default

    First try to determine the cause. Do not... force it, e.g. by using the starter!

    Yes, it could well be a valve, stuck open - as mentioned above. I would remove the rocker arm covers and check if all 16 valves are able to move freely. Also check the pushrods, if all in place and straight.

  6. The Following 2 Users Say Thank You to gringeltaube For This Useful Post:

    Jbulach (06-30-2019), TGP (IL) (06-30-2019)

  7. #5
    4 Star General Jbulach's Avatar
    Join Date
    Nov 2013
    Location
    Sunman Indiana
    Posts
    1,644
    Thanks
    2,356
    Thanked 1,029 Times in 607 Posts

    Default

    This ^ do NOT use the starter! A stuck open valve can usually be coxed back closed by very light taps on the rocker or valve stem with a rubber hammer, but make sure to rotate the piston back away from the valve first. Once it comes back closed, gently bar the engine over and repeat as necessary if it sticks again, until the engine rotates free without hanging the valves.
    M925A2

  8. #6
    4 Star General cucvrus's Avatar
    Join Date
    Dec 2012
    Location
    Jonestown Pennsylvania
    Posts
    7,642
    Thanks
    2,485
    Thanked 5,993 Times in 3,180 Posts

    Default

    So I understand it correctly. You have a truck that ran when parked. You have a replacement injection pump but have not installed it yet. You have looked in the cylinders thru the glow plug holes and poured WD 40 down the intake. Looking in the glow plug holes you will see nothing but the pre-chamber. I am not sure I would go thru the process of removing the valve covers and rocker arms to check if the engine has a valve stuck open. If you are going to change the injection pump anyway you will need to remove the intake manifold. Do that and check the intake valves. If you have a flywheel tool use that. The nice thing about a flywheel wrench/tool is you can rock the engine back and forth to get this loosened up. The 15/16" bolt on the front will tend to loosen or over tighten turning it with that bolt. The flywheel gives you better leverage. I suggested the starter as a method that has worked for me. If it is tight starter or not it will stay tight. Without seeing it only you can make the right decision on what to do. Flywheel turner wrench always worked for me and I had a few with water in the cylinders. I think you are on the right path. But get a flywheel turner tool/wrench and turn it by rocking both ways. Easier than taking the injection pump and rocker arms / covers off the engine. If it were me I would remove the heads and have it done properly. Sitting 10 years did NOT help preserve the head gasket material. I can almost guarantee they are rusted thru at coolant ports. I never seen any yet that were not. Even off good running engines. Good Luck. I am still into the starter method after you have determined no studs or bolts are lodged in the engine. I think it is a stuck valve. Good Luck. Have a Great Day and Be Safe.
    To argue with a person who has renounced the use of reason is like administering medicine to the dead. Thomas Paine: Founding Father Quote.

  9. The Following 3 Users Say Thank You to cucvrus For This Useful Post:

    firefox (07-03-2019), frank8003 (07-01-2019), rtk (07-01-2019)

  10. #7
    4 Star General Sharecropper's Avatar
    Join Date
    Jan 2010
    Location
    Paris KY
    Posts
    1,161
    Thanks
    543
    Thanked 705 Times in 338 Posts

    Default

    I've been thinking about this and, the only thing it could be is a valve stuck open or a bent push rod preventing the cam from fully rotating. If that is indeed the case, my first action would be to remove the valve covers and inspect each valve and pushrod to find the culprit. A valve stuck open can be loosened by spraying penetrating oil on the guide and letting it soak for a bit, and then working the spring up and down with a tool. If it is a bent pushrod, that is easy to remedy by simply removing the bent one and replacing it with a straight one.

    Hope this helps.

  11. #8
    4 Star General sandcobra164's Avatar
    Join Date
    Nov 2009
    Location
    Leesburg, GA
    Posts
    2,920
    Thanks
    162
    Thanked 2,625 Times in 1,065 Posts

    Default

    Just to understand where you are at, is the old injection pump still on the engine or are you halfway into installing the new one? I had a similar issue when installing the 3 bolts into the injection pump drive gear when installing my new injection pump. I had tightened the first two down just a hair too far and my engine seized when trying to bar over to get the third one started. I simply went backwards, loosened the first two until they just cleared the cover and then could get the third one in. Went back through them 2 more times during the tightening sequence and had no more issues.
    84 AM General M923 "General Non-Sense"
    85 Chevrolet M1028 CUCV "Sarge"
    05 Silver Eagle M1102 (Sarge's New 4 Wheeler Hauler)

    Gone but not forgotten....
    71 AM General M35A2 "Big Trucks"
    87 Pribbs Manufacturing M105A2

  12. The Following User Says Thank You to sandcobra164 For This Useful Post:

    frank8003 (07-04-2019)

  13. #9
    Private
    Join Date
    Aug 2017
    Location
    Tampa,Fl
    Posts
    21
    Thanks
    6
    Thanked 9 Times in 6 Posts

    Default

    Hey guys, didnt see any notifications that you guys commented (wierd) but the truck ran perfectly until the ip crapped out. But I agree about not using the starter to free something, the engine is free and it has no water which is good. But I can turn the motor with a breaker bar almost a full rotation before it feels like its hitting against something. Dad even said it sounds like a valve. But how can I tell if it's a valve that's stuck open or a vent pushrod? Thanks for all the tips, and advice from everyone

  14. #10
    4 Star General sandcobra164's Avatar
    Join Date
    Nov 2009
    Location
    Leesburg, GA
    Posts
    2,920
    Thanks
    162
    Thanked 2,625 Times in 1,065 Posts

    Default

    Since you are replacing the injection pump, now's a good time to remove the fuel injection lines, remove the valve covers and do some snooping around. A stuck valve will attempt to stay in the downward position even when the rocker arm does not have tension against it.
    84 AM General M923 "General Non-Sense"
    85 Chevrolet M1028 CUCV "Sarge"
    05 Silver Eagle M1102 (Sarge's New 4 Wheeler Hauler)

    Gone but not forgotten....
    71 AM General M35A2 "Big Trucks"
    87 Pribbs Manufacturing M105A2

  15. The Following User Says Thank You to sandcobra164 For This Useful Post:

    frank8003 (07-01-2019)

Page 1 of 2 1 2 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •