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Technical 235 engine seizes while cranking

Discussion in 'The Hokey Ass Message Board' started by Klunker77, Mar 21, 2020.

  1. My money is still on Squirrel .

    bobss396 and 6inarow like this.
  2. spanners
    Joined: Feb 24, 2009
    Posts: 963


    If you can turn the crank while watching the rocker gear and the rocker gear operates, the cam gear is good. If rocker gear does not move, cam gear knackered. If cam gear good and truck has manual gearbox it could be input shaft getting tangled up in gearbox. Push clutch in while cranking. If auto 'box I'm out of ideas.
    Joined: Dec 14, 2009
    Posts: 2,590


    Stuck valves are common

    if it’s got the fibre timing gears these can strip and break.

    could be a stuck clutch.

    I would pull the valve and side cover while turning the engine over by hand.

    tje trans comes out easy on these as well if it’s a stuck clutch.

    Had an o/t vw bug with a stuck clutch acted like the engine was seized, clutch pedal felt fine.
  4. doyoulikesleds
    Joined: Jul 12, 2014
    Posts: 270


    If the cam gear is broken the distributor would not spin with the crank
    6inarow likes this.
    Joined: Jul 20, 2006
    Posts: 2,423


    Yes that is an easy check pull the dist cap turn the engine and see if the rotor turns, if the rotor turns there is nothing wrong with the cam gear
    Joined: Mar 21, 2014
    Posts: 711

    from okc

    I had the rust in cylinder thing from rain on my big paper air cleaner thru A model hood sides. pull plugs, put trans fluid in, turn back & forth. Leave valve cover off for viewing valve train....don't rule out squirell's real life experience also.....
  7. While we're thinking outside the box a little, get the fan belt off it and make sure that the generator and the water pump turn freely and smoothly. :rolleyes:
    Algoma56, X-cpe and tb33anda3rd like this.
  8. anthony myrick
    Joined: Sep 4, 2009
    Posts: 6,027

    anthony myrick

    Lots if possibilities.
    Had a 272 act similar. Dirt dobbers built a nest on the head.
    Engine turned fine then stopped.
    You couldn’t see it through the spark plug hole.
    Also agree on checking things like the water pump, alt/gen and possibly the starter.
    Had a stuck clutch once but you couldn’t turn anything much.
    The 235 in my sons truck turned at first then stopped. Had a little rust in one cyl and stuck valves.
  9. ffr1222k
    Joined: Nov 5, 2009
    Posts: 1,113


    My daily driver is an OT Thunderbird with a 4 cylinder. Two years ago I turned it off and an hour later it would not turn over. I thought battery but I jumped it and it wouldn't start. I tried pushing it and it drug the wheels. I tried turning with a 3 foot breaker bar. That didn't work either. I was building a stroker motor for it so I resolved to go ahead and pull the engine. When I got to the starter I removed the bolts but couldn't get it out. I moved on to the driveshaft and it turned. I was sure I had it in gear. I went back to the starter and I could get it out. The starter had jammed and the engine couldn't turn. Replaced the starter and it was good to go. May be worth removing the starter just make sure.
    ClayMart likes this.
  10. ekimneirbo
    Joined: Apr 29, 2017
    Posts: 1,368

    from Brooks Ky

    The crank and piston relationship doesn't change. The cam to lifter to valve doesn't change unless the valve sticks open. If one valve were sticking the stoppage should be at appx the same place each time but the op says that is not the case.
    A changing relationship between the crank and the cam could cause random stoppages and forcing the engine past that point can damage things. If you remove the valve cover you can check which valves are closed and which valves are depressed when it sticks..........and see if a valve is stuck by checking the rocker arms. Rotate backwards then come forward again and see where it locks up. If the rotation point of lockup changes, I would check the timing gears.
    Also, I would check the starter as suggested above.
  11. lippy
    Joined: Sep 27, 2006
    Posts: 4,854

    from Ks

    I have had old starters that would turn an engine a little then start dragging and stop. Took them off tried to run it on the bench, same thing. Lippy
  12. RichFox
    Joined: Dec 3, 2006
    Posts: 9,948


    Never played with a 235. But a 270-302 GMC will absolutely run the rods into a cam lobe if the cam timing is off. For sure.
  13. Im still betting on Squirrel,,,,,and now Richfox !

    41 GMC K-18 likes this.
  14. donsz
    Joined: Nov 23, 2010
    Posts: 211


    I had a similar situation with a 261 (rotated at first then tightened up, and with rest rotated again). In my case the oil
    pump was not working correctly, because the oil pump was not primed before starting the engine. You probably already know that the distributor drives the oil pump. I took the distributor out and used a flat head screwdriver shaft attached to a drill to prime the pump. That may not be your problem, but I thought I would share a similar experience and resolution.
    Klunker77 likes this.
  15. fastcar1953
    Joined: Oct 23, 2009
    Posts: 2,161


    Starter ,cables,timing,battery,ignition switch,wiring. Start with the basics. It did run not to long ago right?
  16. Likely, stuck valves since it has been sitting. Pretty easy to narrow that down. Definitely try it with the clutch pushed in first. If working alone, block up the wheels and jam the pedal down with some wood. Try to spin it at the damper with a socket and breaker bar.
    Klunker77 likes this.
  17. Klunker77
    Joined: Oct 20, 2019
    Posts: 17


    Hey everyone. Just thought i would give an update. I added some Mystery oil and let it sit for a day and a half. Good news- it turned over freely. Bad news- I still can’t get the truck to start now. Timing seems good. All my cables are good and clean. I have spark. My battery was fully charged. When I went to start it it went “Wuh Wuh Wuhrooooo” and then it quick cranking ( hope those sound effects make sense) Tried again, same thing. Hopefully I can get this mess sorted out sooner than later! I think I’m going to swap out the battery regardless and also am beginning to think the starter is worn out. Any new suggestions on this?
    VANDENPLAS likes this.
  18. jimmy six
    Joined: Mar 21, 2006
    Posts: 6,918

    jimmy six

    That GMC is rejecting the lowly 235 Chevrolet engine and wants it's 270 Jimmy back.
    Klunker77 and s55mercury66 like this.
  19. BoogittyShoe
    Joined: Feb 18, 2020
    Posts: 330


    Yep. Sounds like the starter.
  20. Has that got a key start or foot stomp start?
  21. fastcar1953
    Joined: Oct 23, 2009
    Posts: 2,161


    new 12 volt starter and new battery plus cables.
  22. Doublepumper
    Joined: Jun 26, 2016
    Posts: 648


    Good idea to clean all the battery and ground connections. Verify the battery and starter cables are in good condition and the cable ends are firmly connected/crimped to the cables and corrosion free. Best to do these things before buying parts.....that may not be needed.
    Klunker77 likes this.
  23. Klunker77
    Joined: Oct 20, 2019
    Posts: 17


    It has the foot starter

    Sent from my iPhone using The H.A.M.B. mobile app
  24. BoogittyShoe
    Joined: Feb 18, 2020
    Posts: 330


    Nope. It's the starter. I could tell by the way it sounded.
    anothercarguy likes this.
  25. jaracer
    Joined: Oct 4, 2008
    Posts: 433


    Before you start swapnostics, why don't you check what the battery voltage does when it quits cranking. It should have 6.3 volts or above before you begin to crank, and stay above 4.5 volts while cranking. Also check the voltage at the positive post while cranking and at the starter terminal. They should be within about 0.2 volts. More than that means you have a voltage drop in the positive cable. Also check between the starter housing and the negative cable while cranking. Anything over 0.1 volts means you have a poor ground.

    If the battery voltage is above 6.3 and drops below 4.5 volts while cranking it means either the battery has given up the ghost or the starter is drawing too much current. Having the battery tested is the easiest unless you have access to a high current ammeter to test starter draw.
  26. Budget36
    Joined: Nov 29, 2014
    Posts: 3,930


    Or he fouled the plugs with the oil
    sunbeam likes this.
  27. Klunker77
    Joined: Oct 20, 2019
    Posts: 17


    Thanks for the Info, I’ll be sure to test this first before yanking anything apart. This is however a 12v system. Will those voltages just double?

    Sent from my iPhone using The H.A.M.B. mobile app
  28. jaracer
    Joined: Oct 4, 2008
    Posts: 433


    Yes, your battery should be at least 12.6 volts and shouldn't drop lower than 9.6 volt while cranking. The 0.1 volt drops remain the same.
  29. sunbeam
    Joined: Oct 22, 2010
    Posts: 4,956


    From your post Engine is hard to turn by hand so there goes the starter idea. Did the engine turn backward after lockup? If it did could be the cam gear but my first thought is carbon because of blue smoke and oil driping from tailpipe. I'd pull the head sounds like the engine need work any way.
    tractorguy and firstinsteele like this.
  30. I had a similar thing happen on my '47, and it turned out to be the foot operated contact on the starter was black and full of gunk. I took it apart, cleaned and filed all the contact surfaces, re-assembled it, and it has'nt missed a beat yet.

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