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b16 and b18 crank specs

Discussion in 'Engine Building' started by wannaberacer, Sep 30, 2003.

  1. wannaberacer

    wannaberacer Member

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    I'm just curious to know if a b16 crank is interchangeable with a b18c crank. I.E., will a b18c crank fit in a b16, or will a b16 crank fit in a b18c?
     
  2. NoJokE

    NoJokE Senior Member

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    Yes
     
  3. phunky.buddha

    phunky.buddha Admin with a big stick Admin VIP

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    :yes:
     
  4. GSRCRXsi

    GSRCRXsi Super Moderator Moderator VIP

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    :yes: and according to c-speedracing's compression calculator, it considerably bumps your compression with the b18c crank in the b16, but with the b16 crank in the b18c it will drop it down pretty low
     
  5. rsaeini

    rsaeini Senior Member

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    so you can put a B18C1/5 crank in a B16A, but which rods do you use???
     
  6. rsaeini

    rsaeini Senior Member

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    how did you use the c-speed calc to figure out compression/displacement???

    what were the options that you put in? that calc. doesn't give you the option of selecting the crank.

    also, what would the stroke be with a B18C1 crank in a B16A2 block using B16A2 pistons and rods ???
     
  7. GSRCRXsi

    GSRCRXsi Super Moderator Moderator VIP

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    i know you cant directly put in the crank, but you can put in the stroke, which is what the crank does. if you look where you select the block, its programmed dimentions pop up and you can see what the stroke and bore of each engine is. with your setup stroke will be 87.20mm. rod length and pistons dont affect stroke, only where in the block the stroke is taking place. the only thing im not sure of is what the piston to deck heigh will come out to be, so i dont really know the exact compression, just if it will be more or less. for example, with the b16 crank in a b18 block, you get a low compression 1.6l engine, now how low the compression is would be depended on the rods used, a longer b18 rod will push the piston closer to the head, yeilding higher compression, and vice versa.

    so lets take your example:
    B18C1 crank (87.2mm stroke)
    B16A2 block (81mm bore)
    B16A2 pistons (6.01cc dome)
    B16A2 rods

    now since the deck height is shorter for the B16 then the B18 blocks, its safe to assume that the piston will be comming closer to the head, thereby decreasing the piston to deck height and increasing compression alot as well. but since we are using the shorter b16 rods, that will then decrease the piston to deck height. i dont know the exact specs on the rods, so lets assume that it puts the piston to deck height back to normal for a b16a2 (.020). given all that, you now have a 1.8l engine in a b16 block that has ~11.4:1 compression. i think it will be higher compression though since i was assuming the shorter rods put the piston to dec height back to normal, but i think in actuality it will still be <.020 thus yeilding a compression >11.4. :)
     
  8. phunky.buddha

    phunky.buddha Admin with a big stick Admin VIP

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    Well, given that the B16's pistons are only .5mm "in the hole" (0.020 inches), pushing the piston up 5mm at the top of the stroke with the GSR crank and the B16 rods- you would probably end up slamming into the top of the combustion chamber. You'd want to run custom rods with that setup- like 130mm or something... which would bring your rod/stroke ratio down to 1.49. Definitely not good for revving like the B16 does stock.
     
  9. GSRCRXsi

    GSRCRXsi Super Moderator Moderator VIP

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    yea i was just throwing the numbers out there to prove my point, i didnt know the exact lengths.
     
  10. wannaberacer

    wannaberacer Member

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    I was actually thinking of the idea of trying to put a b16 crank in a b18c since I can get a higher rod ratio out of the higher deck height. Then I would get some custom rods to get that rod ratio, turbo the bugger and rev to happiness.
     
  11. wannaberacer

    wannaberacer Member

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    BTW: anybody know of any papers or tests done with rod ratios for 4 valve engines? Particularly the preferred r/s ratio for certain RPM's.
     
  12. phunky.buddha

    phunky.buddha Admin with a big stick Admin VIP

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    No, that gets pretty expensive to test...

    If you increased the length of the rods in a GSR engine to 143mm and then ran a 77mm B16 length stroke, you would have a nice high ratio of 1.86.
     
  13. saturn_boy96

    saturn_boy96 88 C1V1C 53D4N DR1V3R

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    but when your rod ratio gets too high your piston speed gets to slow. losing VE which is what 4 bangers thrive on.
     
  14. jamesA

    jamesA Well known pissed off telephone guy VIP

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    if you put the B18C crank in your B16A, what kinda fuel will you need? min of 95 octane? that sounds like a fun Idea.....


    *keeps getting expensive ideas*
     
  15. wannaberacer

    wannaberacer Member

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    wait a sec, doesn't a longer r/s ratio give you longer dwell at TDC and BDC and increase piston speed.
     
  16. phunky.buddha

    phunky.buddha Admin with a big stick Admin VIP

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    Higher ratio = more dwell time
    Lower ratio = higher piston speed
     
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