How bad is it to rotate the engine backwards

Discussion in '80-Series Tech' started by excessive, Jul 26, 2011.

  1. excessive

    excessive

    Messages:
    395
    Location:
    Charleston, sc
    97 LX 450

    I did a search, but did not come up with any answers.... so anyway, while doing the replacement of the oil pump seal I accidentally rotated my engine in the wrong direction (counter-clockwise) when trying to loosen the crank pulley bolt. How bad is this? Anything I should check for damage? I have done some goggling and it seems that it could damage the timing chain / tensioner

    This little project just may cause me my sanity:bang::bang:
  2. Kernal

    Kernal

    Messages:
    4,681
    There's been a few threads about it and someone did it in the past without any issues. Wait for someone who's actually pulled an engine apart to chime in with a better answer.
  3. kidglove13

    kidglove13

    Messages:
    3,578
    Location:
    Richmond, VA
    I did it with out issue, I did not rotate it alot but I did rotate it backwards FWIIW
  4. Tools R Us

    Tools R Us

    Messages:
    17,827
    Location:
    Chandler, AZ
    Not going to damage anything.
  5. excessive

    excessive

    Messages:
    395
    Location:
    Charleston, sc
    thanks for the info guys.

    I was trying very carefully not to rotate backwards, but my 14mm socket slipped off the flywheel and the engine rotated about 1/4 a revolution in the wrong direction. :doh::doh:
  6. robertaleon

    robertaleon

    Messages:
    568
    Location:
    Sacramento, CA
    Same job - wife helping while I was underneath watching the 14mm, she rotated about 1/6 of a turn on the 30mm counter-clockwise ("Ooops - I'm a girl"). No harm done.

    Did you find the socket?
  7. excessive

    excessive

    Messages:
    395
    Location:
    Charleston, sc
    not yet, i bought this today, when i get home from work i will check out the inside the bellhousing.
    [​IMG]
  8. js93cruiser

    js93cruiser

    Messages:
    2,160
    Location:
    roseville, ca
    i know on the 22re engine it will loosen the tensioner and skip teeth on the timing chain....might be the same for the 1fz
  9. alia176

    alia176 SILVER Star

    Messages:
    8,435
    Location:
    Tijeras, NM
    you're fine. I've rotated engines backwards more times than I can count.
  10. Tools R Us

    Tools R Us

    Messages:
    17,827
    Location:
    Chandler, AZ
    Maybe, if the chain is big time stretched, parts are very worn, but I have never seen it happen. Have done or seen to done tons of times. Attempt a big obstacle, fail, slide backwards, the tire force kills the engine, turns it backwards, collect your thoughts, start the engine, make the obstacle, no harm, no foul.:hillbilly:
  11. excessive

    excessive

    Messages:
    395
    Location:
    Charleston, sc
    I think the chain tensioner in our motor works by simply pressing on the timing chain, so hopefully that would not cause timing to be messed up. I know in the shop manual it says do not turn the motor in the wrong direction.

    Hopefully it will be ok - I guess I'll find out if/when i get everything back together.

  12. Pin_Head

    Pin_Head

    Messages:
    11,505
    Location:
    OC, CA
    My buddy's son parked his Toyota pickup with 22re on a hill and left it in 4th gear without the parking brake on. Overnight, it slowly rolled down the hill with the engine turning backwards about 200 yards to the bottom of the ravine. After winching it out, it started right up. No damage!

    YMMV
  13. CJF

    CJF

    Messages:
    6,386
    ^^^
    Too funny.

    My own bone-head maneuver was to try to push start my 82 Toyota Longbed (22R) by letting it roll backwards and then popping the clutch. Guess what gear I *wasn't* in. :lol:

    That was back in 1995. Still driving it today with no issues.
  14. Tools R Us

    Tools R Us

    Messages:
    17,827
    Location:
    Chandler, AZ
    Most shop manuals say that. Likely not because of causing damage but, it is bad technique. When a motor is turned backwards, the timing relationship between the crank (timing mark) and the cam (distributor, etc) changes, so parts can be installed out of time, etc. You can turn it backwards, then just need to turn it back forwards enough to remove the slack, restore the timing relationship.
  15. TX Cruiser

    TX Cruiser

    Messages:
    622
    Location:
    Austin, TX
    You mainly worry about that on interference motors. One of mine requires that you rotate the engine 10 degrees CC to properly tension the timing belt. Once the timing is verified, I always have to rotate it backwards to get the balance shafts to sync. Belt stretch.

    It's going to be a damn good "pop" if harm was done. Matters not what you have, belt or chain. As reiterated above, no harm.
  16. Wrench

    Wrench Wheeling With Rock Buggies And Breaking Like Them.

    Messages:
    3,966
    The engine runs backwards when you drive in reverse. So no harm done.
  17. excessive

    excessive

    Messages:
    395
    Location:
    Charleston, sc
    Thanks for the replies everyone, i don't feel worried about it anymore! I knew i was just being paranoid, but I am building this rig for ultimate reliability, so I wanted to make sure im not jeopardizing reliability in any way.
  18. neoworm

    neoworm

    Messages:
    919
    Location:
    North Vancouver, BC
    :confused::rolleyes: might wanna think about that.
  19. Conundrum

    Conundrum

    Messages:
    99
    Location:
    Boise, Idaho
    I had a 550 Polaris snowmobile that had the engine "reverse" directions to go in reverse.
  20. cruiserdan

    cruiserdan SupportingVendor Emeritus Moderator Supporting Vendor

    Messages:
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    Location:
    Sniffin' diesel
    What?


    :doh:

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