Results 1 to 10 of 10

Thread: Crank journal wear.

  1. #1
    Negative Reputation Domestic Engineer Howieau's Avatar
    Join Date
    Nov 2005
    Location
    Queensland
    Posts
    507

    Default Crank journal wear.

    Im purchasing some ACL race bearings soon for my engine. They come in standard, 0.25" and 0.5" - Mine crank journals are fine and show no sign of scratching or anything. Does that mean I order the standard size ones? Or do the journals wear over time and should go to 0.25"?

    Is there some way I can measure my journals.

    Cheers

    Edit: My car has had no spun bearings or anything. There was slight scratching on the surface of a main bearing I think it was when I was pulling my engine apart but all crank journals are smooth as.
    Last edited by Howieau; 18-06-2007 at 06:30 PM.
    "There is a better way to do it, find it" -Thomas Edison

  2. #2
    umop apisdn Chief Engine Builder twentyEight's Avatar
    Join Date
    Jul 2006
    Location
    Queensland
    Posts
    3,108

    Default Re: Crank journal wear.

    I have been meaning to ask the exact same question...
    ([][][]II--LT--II[][][])


    Green '77 RA28 Celica - VVTi V8 Goodness...

  3. #3
    Toymods Club Member Too Much Toyota TooF's Avatar
    Join Date
    Sep 2005
    Location
    NSW
    Posts
    5,741

    Default Re: Crank journal wear.

    you should go take your crank to your machinist and the crank will probaly be need to be ground undersize. if it is in good shape to start with just grind it to 0.25 undersize.

  4. #4
    Long Time Reader Backyard Mechanic willwal98's Avatar
    Join Date
    Dec 2005
    Location
    Queensland
    Posts
    377

    Default Re: Crank journal wear.

    take it to a machine shop and the can put the micrometer on it and tell you exactly. Depending on what engine you have and what sort of life it's had it might be an idea to get them to double check it also. Mini's are really bad for crank wear because the engine and gearbox share the same oil and first gear is non-syncro. They also chew oil pumps because the pump is before the oil filter.

    Edit: If I didn't type so much I would have got in first . I blame mini's for my long response too. Damn cars.
    Hello.

  5. #5
    doctor ed Conversion King ed's Avatar
    Join Date
    Sep 2005
    Location
    Penrith BC
    Posts
    2,537

    Default Re: Crank journal wear.

    Quote Originally Posted by Howieau
    Is there some way I can measure my journals.
    and you are rebuilding this engine yourself? ok...

    ...go straight to a machinist, do not pass go, do not collect $200. at the very least you should linish the journals, and at the other end they may need regrinding to remove defects. in either case the wear needs to be measured with a set of micrometers and they will then tell you what size bearing to buy

    cheers
    ed
    ../delete/ban
    tech moderator
    E46 M3 Nürburgring Nordschleife - 8.38

  6. #6
    Toymods member no 341 Domestic Engineer amichie's Avatar
    Join Date
    Dec 2005
    Location
    NSW
    Posts
    649

    Default Re: Crank journal wear.

    You measure the oil clearance with plastigauge. Calipers etc will only give you a ball park figure.

    You should only use undersize bearings on a reground crank.

    So your options are
    1. Take it to a machine shop and get it meaured. Any decent machine shop will tell you they will need the rods and the block to measure it properly. Regrinding will cost approx $150 to $250 depending on number of cylinder etc.

    2. Rebuild with standard size bearings and just a good clean up. If you do this there is no point in buying the race series bearings and you will generally be taking a much greater risk of reduced life span.

    I would go option 1. But if you know the history of the engine and you know the crank has not been ground before and there is no sign of gooves on the journals etc then buy the standard size replacements. Worst case is you will be pulling it apart again and choosing option 1.

  7. #7
    Gobble, Gobble! Automotive Encyclopaedia mrshin's Avatar
    Join Date
    Nov 2005
    Location
    Montrose
    Posts
    1,154

    Default Re: Crank journal wear.

    Calipers and a micrometer are slightly different things...

  8. #8
    The Aberrational Chief Engine Builder Andrew162's Avatar
    Join Date
    Nov 2005
    Location
    NSW
    Posts
    3,148

    Default Re: Crank journal wear.

    Quote Originally Posted by willwal98
    Mini's are really bad for crank wear because the engine and gearbox share the same oil and first gear is non-syncro. They also chew oil pumps because the pump is before the oil filter.
    my sister is putting a rebuilt engine into her Mini (heavy little bastard engine for the size ) as far as I know it's a stock block, fully rebuilt inc. dished pistons, 1100cc stroker crank and all the good guff. her engine should last a long time though, from the list of stuff on the invoice for the rebuild, it looks very solid.

    sorry, slightly OT...
    Clicky -> THEN: 1999 RAV4/GT-Four Hybrid
    Clicky -> NOW: 1985 ST162 Celica SX (Gen III 3S-GE) - Kitted & Resprayed


    TRIKKE | Video

  9. #9
    Long Time Reader Backyard Mechanic willwal98's Avatar
    Join Date
    Dec 2005
    Location
    Queensland
    Posts
    377

    Default Re: Crank journal wear.

    Make sure you change the oil and filter more often than for a normal car. Also don't select first gear until the car is stopped completely unless she can double clutch.
    Hello.

  10. #10
    The Aberrational Chief Engine Builder Andrew162's Avatar
    Join Date
    Nov 2005
    Location
    NSW
    Posts
    3,148

    Default Re: Crank journal wear.

    haha, she's owned a Mini before.. this is a girl who used to reverse-clutch-start her last Mini (down our old front lawn) because it utterly refused to kick over for a cold-start.
    Clicky -> THEN: 1999 RAV4/GT-Four Hybrid
    Clicky -> NOW: 1985 ST162 Celica SX (Gen III 3S-GE) - Kitted & Resprayed


    TRIKKE | Video

Similar Threads

  1. 7afe crank specs and internal differences year to year
    By twinky in forum Tech and Conversions
    Replies: 7
    Last Post: 08-05-2007, 01:39 PM
  2. Light-weight Crank Pulley's
    By JetspeedCamry in forum Tech and Conversions
    Replies: 11
    Last Post: 12-02-2007, 07:40 PM
  3. Wanted PART NUMBER DB86 Cressida Wear indicators.
    By RT104GT in forum Tech and Conversions
    Replies: 0
    Last Post: 22-09-2006, 02:28 PM
  4. bigport crank in a gze
    By AE101LEV in forum Tech and Conversions
    Replies: 19
    Last Post: 07-04-2006, 10:15 AM

Bookmarks

Posting Permissions

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