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CR-VTEC? crank and rods?

Discussion in 'Engine Building' started by gettocrx, Oct 17, 2006.

  1. gettocrx

    gettocrx Member

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    Hey guys! I'm helping my homeboy put together his crvtec block. He already has high comp pistons with pr4 rods and stock crank. He spun rod bearing #1 resulting in gouging the crank, so the crank ain't reuseble. So we're planing on changing out the crank and rods also! Can we stroke it? what crank with what rods would make shall we use? Thanks!
     
  2. GSRCRXsi

    GSRCRXsi Super Moderator Moderator VIP

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    youd need a custom crank and custom rods.
     
  3. tartymctang2357

    tartymctang2357 Grand High Wizard

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    whats the compression height on your pistons? if you're using just stock crv pistons and a b20a crank (95mm stroke) and b17 rods (132mm) you can stroke the engine the only problem is that you're not using the stock pistons if the compression height is the same as the stock then it'll work and give you a r/s ratio of 1.39 which is kinda shitty for reving high but you'll have a stroked motor so that won't matter as much use this equation to figure stuff out if you can find out the right lengths of things to fit in your block


    Block Deck Height = (Stroke/2) + Rod Length + Compression Height + Stock Deck Clearance


    hope that was clear if not just let me know what wasn't and i'll try to clear it up
     
  4. alterdcreations

    alterdcreations Member

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    aren't the b18 a/b cranks the same as the b20 crv crank(b20a)?

    i dont know of any b series crank(factory) that is 95mm
     
  5. tartymctang2357

    tartymctang2357 Grand High Wizard

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    b20a is an older prelude crank
     
  6. alterdcreations

    alterdcreations Member

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    i heard about that a while back (forgot engine code)
    i heard somthing that those cranks will need to get balanced in order to operate smoothley. what do you think a safe rpm to rev with that crank would be?
     
  7. alterdcreations

    alterdcreations Member

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  8. tartymctang2357

    tartymctang2357 Grand High Wizard

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    yea probably gotta notch your block, and reving umm well probably only be able to rev to like 6500 or 7000, but you should have a lot of torque
     
  9. alterdcreations

    alterdcreations Member

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    6500 to 7000 with oem rods.
    maybe more with aftermarket rods
    7500 to 8000 rpms i think would be kinda safe with crower or probe
    that would be one very strong engine
     
  10. lsvtec

    lsvtec GNU/Linux Evangelist

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    I don't think that B20a crank will fit in your B18/B20b block.
     
  11. alterdcreations

    alterdcreations Member

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  12. tartymctang2357

    tartymctang2357 Grand High Wizard

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    b18a/b and b20 block heights are 211.84mm

    Block Deck Height = (Stroke/2) + Rod Length + Compression Height + Stock Deck Clearance


    so if you use the smallest b-series rods you can get and assuming hes using b20b/z pistons for the compression height and using stock deck clearence and the b20a crank's stroke, the numbers are as follows

    stroke of b20a crank (95mm)
    length of b17 rods (132mm)
    b20b (p3f) piston compression height (29.95mm)
    stock deck clearence on a b20b is (.76-.84mm)

    so add it all up you end up with (using the max deck clearence) 209.93mm which will safely fit into the b20b, the rod stroke ratio would end up being 1.39

    if you had a b18c1 or c5 the stock clearence there is 212.39 mm so you could use b16 rods and stroke it even more, and have a better r/s ratio 1.41
     
  13. alterdcreations

    alterdcreations Member

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    i wish i understood what the f@#k you just said
    just kidding
     
  14. MikeBergy

    MikeBergy Blah blah blah....

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    Just get an ls crank and aftermarket rods and pistons and call it a day. Unless you know exactly what you are doing, I wouldn't recommend the b20a crank route.
     
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