Page 1 of 4 123 ... LastLast
Results 1 to 10 of 34

Thread: trying to put motor together, crank is hard to turn

  1. #1

    trying to put motor together, crank is hard to turn

    SBC . put the crank, rods, and new bearings all in. fresh from the machine shop. I noticed it is hard to turn about half way around. took the rod caps off and noticed some bearing wear already showing. prolly only turned it 8 turns just playin around. is this normal? should it turn easliy all the way around? yes I did use assembly lube. WTF

  2. #2
    Senior Member RACING JUNKIE
    Join Date
    Sep 2007
    Location
    orland pk il
    Posts
    2,429
    DID YOU MIC CRANK PRIOR TO ASSEMBLY? CHECK CLEARANCE? http://www.plastigaugeusa.com/

  3. #3
    Senior Member EXPERT BUILDER
    Join Date
    Nov 2008
    Posts
    263
    x2
    if u didnt put some plastiguage to it and make it had good clearence that would explain it

  4. #4
    Senior Member RACING JUNKIE
    Join Date
    Jan 2006
    Location
    La.
    Posts
    2,890
    Not normal at all, there could be a number of issues. Crank not turned round, not to size, or rods could be out of round. An assembled short block, sm/blk should turn over at about 20lbs torque with all new bearings, rear main seal and rings. in fact the last b/blk i assembled turned over at 20lb or less.

    JMO

    Zip.

  5. #5
    Senior Member RACING JUNKIE
    Join Date
    Sep 2007
    Posts
    4,143
    STUPID QUESTION BUT HERE GOES....

    Did you make sure not to mix up any rod and or main caps? Also..if your crank has a large fillet radius and you do not have chamfered bearings OR you Do have chamfered bearings and you mixed up the upper and lowers, it will do that.

  6. #6
    Senior Member RACING JUNKIE
    Join Date
    Jun 2003
    Location
    Hobbs, NM
    Posts
    842
    Quote Originally Posted by Tod74
    STUPID QUESTION BUT HERE GOES....

    Did you make sure not to mix up any rod and or main caps? Also..if your crank has a large fillet radius and you do not have chamfered bearings OR you Do have chamfered bearings and you mixed up the upper and lowers, it will do that.
    X2 on what todd said. Did the crank spin easily without rods and pistons?

  7. #7
    Senior Member RACING JUNKIE
    Join Date
    Feb 2004
    Location
    san antonio, texas
    Posts
    1,233
    yea should feel and turn smoothly, check size on mains with just
    bearings and then check the size of the crank, same with rods,
    torque them down with bearings only, and some plastigauge, take your
    time and double check the journals, i used clevite and king bearings
    w/o a problem, check to see if you need chamfered bearings,
    good luck :wink:

  8. #8
    Senior Member RACING JUNKIE
    Join Date
    Nov 2004
    Location
    St. Louis, Missouri
    Posts
    664
    If clearances check out ok and you did not mix up the connecting rod caps,
    how bout putting a screw driver between the main journal and crank counter weight, applying a tiny amount of pressure before sunggin down the main caps, then snug them down while pressure is applied? then begin torque sequence. I usuall do this on 3 & 4th main caps. Seems to work every time.
    Also check your end play clearances
    Are Maincaps facing front of crank correctly?

    Sorry, Gotta Ask.

  9. #9
    Senior Member EXPERT BUILDER
    Join Date
    Nov 2003
    Location
    NORTHEAST
    Posts
    290
    Also check for run out as the crank may not be straight.
    WWW.CNCBLOCKSNE.COM
    IS A DIVISION OF
    HINKSON AUTOMOTIVE
    RESEARCH & DEVELOPMENT

    CARL HINKSON 207-892-7215
    EMAIL CHINKSON@JUNO.COM

  10. #10
    Senior Member SENIOR BUILDER chevynovaman's Avatar
    Join Date
    Sep 2008
    Location
    CENTRAL WISCONSIN
    Posts
    114
    I HAD THAT PROBLEM ONCE, MY SHOP TEACHER NUMBERED THE MAINS FROM THE BACK OF THE MOTOR, INSTEAD OF THE FRONT. MY CRANK WOULDNT TURN AT ALL... MAINS WERE ALL BACKWARDS... WE GOT IT STRAIGHTENED OUT THOUGH...
    1968 CAMARO 302 4 SPD IN THE ROUGH
    1957 CHEVY FUEL INJECTED LS1 4L60E BEAUTY
    1962 CHEVY II NOVA 496 LETS RACE


Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Email us - Support@RacingJunk.com
Call us - 866.326.9227
Copyright © 2005-2016 RacingJunk.com All Rights Reserved.

Designated trademarks and brands are the property of their respective owners. Use of this Web site constitutes acceptance of the RacingJunk.com
Terms of Use, Classifieds Disclaimer, Privacy Policy, and Cookie Policy