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How to tell what size rod bearings

Discussion in 'Engine Building' started by wikedeye, Mar 10, 2009.

  1. wikedeye

    wikedeye Well-Known Member

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    I am going to buy eagle rods for a b16a and I am not sure how to determine which bearings I will need. I know how to tell what size I need for the crank, but not for the rods. Any advice?
     
  2. MthaFuknGreen

    MthaFuknGreen Green on the scene.

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    purchase a micrometer set and get to measuring.
     
  3. wikedeye

    wikedeye Well-Known Member

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    Do you just measure the inside of the rod, then the crank? Then take the difference and do what? How much space should be left over between the bearing and the rod. A little more info would be helpfull.
     
  4. eastbxc

    eastbxc Custom User Title

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    Agreed. I am interested myself.
     
  5. MthaFuknGreen

    MthaFuknGreen Green on the scene.

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    How to use a micrometer

    for a decent set of inside and outside micrometers, itll probably run you at least $2500, so maybe you could go to a shop and have them help you out.
    but yeah, use an inside mic to measure the the rod and make sure to measure taper and and out of round as well and then use an outside mic to measure the cranks rod journals, measuring taper and out of round on that too. then determine the oil bearing clearance specs by either buying the manual for your engine or im sure someone could give you a good range to work with.

    youll probably just need to measure the rod journals on the crank because im assuming that wherever youre buying the rods from would have the specs and measurements.
    or you could just find the specs for the crank in your engine and assume that it hasnt been worn down to much..
    Honda Engine Specs
     
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  6. wikedeye

    wikedeye Well-Known Member

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  7. MthaFuknGreen

    MthaFuknGreen Green on the scene.

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    reading a standard micrometer can be a pain in the ass to learn, but once you do its easy.

    cliff notes for reading a standard mic-
    whatever size mic it is = the first number. example, 1-2" mic reading should have a 1.xxxx.
    whatever number you can see on the sleeve, is the second number. example: 4. so far the reading is 1.4xxx.
    each line after the number is worth 25 thousandths.
    say its two lines past the 4, .025 + .025 = .050.
    the reading so far is 1.450x
    then add how ever many lines on the thimble there is and ad that to the .050.
    say its 23 lines up, each line is worth .001.
    so the measurement is 1.473x.
    if there is a vernier scale on it, then it can measure to the ten-thousandths place and you only need it if the line on the thimble doesnt line up perfectly with the index line on the sleeve.
    if the line doesnt line up, you just look for whatever line lines up perfectly with any of the lines on the vernier scale and tack that number in the place of the last x.

    metric mics are soo much easier.
     
  8. eastbxc

    eastbxc Custom User Title

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    Someone rep green for me it says I need to spread it around first. Thanks for the great info.
     
  9. boostin4fun

    boostin4fun Boosted ls/vtec ohh yeah!

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  10. MthaFuknGreen

    MthaFuknGreen Green on the scene.

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    i just remembered how to measure the oil clearance!
    lol
    plastigage.
     
  11. wikedeye

    wikedeye Well-Known Member

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    I hit him with some rep.
     
  12. brian11to1

    brian11to1 Senior Member

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    since the machine shop spec'd my block and crank out and said I'd be good with just OEM green bearings, I went with ACL standards... used plastigauge and was set.
     
  13. boostin4fun

    boostin4fun Boosted ls/vtec ohh yeah!

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    I have used acl's in my last 3 builds with great success also. I have heard many people trash talk them but half of those people have not used them personally or dont know how to build and tune shit in the first place.
     
  14. wikedeye

    wikedeye Well-Known Member

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    I am sure greens would work, but I would rather have the best fit possible. I am just going to have the machinist tell me when I get the block honed, because I dont really want to buy all the tools I would need to properly check it myself
     
  15. Jared759

    Jared759 Well-Known Member VIP

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    Remember, machine shops can sometimes make mistakes. Its always good to check everything multiple times.
     
  16. MthaFuknGreen

    MthaFuknGreen Green on the scene.

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    definitely would be cheaper.
    anyone can make mistakes, but the machine shop probably has more experience with measuring stuff accurately.
     
  17. wikedeye

    wikedeye Well-Known Member

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    They do sometimes make mistakes, but plastigauge is cheaper then micrometers. Even if I buy what they tell me and they are wrong I can check it and get a bearing or two where needed. Still cheaper then micrometers.
     
  18. MthaFuknGreen

    MthaFuknGreen Green on the scene.

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    but plastigage is for checking bearing oil clearance.
     
  19. wikedeye

    wikedeye Well-Known Member

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    Yeah I know. If the shop tells me get X size bearing and I put in with the plastigauge then I will know if the clearance is to little or to great. Then I will know what size I actually need.
     
  20. MthaFuknGreen

    MthaFuknGreen Green on the scene.

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    do you know how to use plastigage?
     
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