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Mini-Swap help

Discussion in 'HYBRID -> ED-EF / DA' started by swapdohc, Oct 14, 2003.

  1. swapdohc

    swapdohc Member

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    I recently bought a SOHC VTEC head I intend to swap onto my 91 Civic Si.
    There are two different D-series SOHC VTEC heads, one from the later model Civic EX (96-00 D16Y8) and one from the earlier Civic Si (92-95 D16Z6). I have been told that the post swap compression ratio's between the two heads are hugely different. One resulting in prox a 9 to 1 and the other an impressive 11 to 1. Does anyone know if this is true and which one is which?

    The head I have is maked with "P2j-3" and "97" on the exhaust side of the head, If anyone can tell what motor this head is from please let me know.

    Thank you in advance for any help, this is my first "Inter-motor" mating attempt!!!
     
  2. cointelpro

    cointelpro Senior Member

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    im lookin for the same info. :D except i got a lowsy 91 dx :(
     
  3. SiMpS

    SiMpS Junior Member

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    Me too, Done a little searching around to no avail...only block codes
     
  4. phunky.buddha

    phunky.buddha Admin with a big stick Admin VIP

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    D16A6 bottom end with D16Z6 head = 9.96:1 compression
    D16A6 bottom end with D16Y8 head = 10.33:1 compression

    Compression ratios NOT calculated with the vaporware "think" Y8 gasket.

    Pop the valve cover on your head first to make sure it's a VTEC head- you'll have 20 lobes on the cam. You should also have a VTEC solenoid on the back side... the major visual difference between the Z6 and Y8 heads is in the combustion chamber shape/size. If you look at the combustion chambers you can identify which head you have. The Z6 has round combustion chambers, and the Y8's are rectangular shaped. Well, it's really the quench pad area that you're looking at, but the shape where the combustion chamber meets the head surface is what you need to look at to determine which head you have.

    Round = Z6
    Rectangular = Y8

    Simple.

    By the way, just for reference- the Z6 is coded P28, and the Y8 is coded P2P. I don't know if those same markings are supposed to be on your head..
     
  5. swapdohc

    swapdohc Member

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    Thanks for the info!!!!!

    I have also found some good sites to reference:

    http://crx.honda-perf.org/articles/moremin...moreminime.html

    http://www.makuragi.s5.com/civic_99/Y8maniswap/

    http://www.geocities.com/c_rexboy/minime.html


    I just aquired a 50k mle D16Y8 with a blown bottom end for $20!! Can you say SCORE!!! I will be swaping on the head (To be ported and polished), intake manifold and fuel rail next weekend. I will let you know how it turns out.


    Does any one know if there are any draw backs to putting a VTEC activation switch at the bottom of my gas peddle. I figure I can set it up so that I have full throttle an 1/8 inch from the floor and set up the switch so that it can be activated at any time. Any imput would be apreciated as switching to OBD1 seems to be a pain in the A$$.

    Thanks and Happy Swapping!
     
  6. Jim Truett

    Jim Truett Senior Member

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    I wouldn't recommend using a switch like that. If you mashed the throttle and triggered the VTEC at too low of an RPM, there would be a potential for engine damage due to the oil pressure being too low. Use an MSD RPM activated switch to control the VTEC if you don't want to go OBD-1.
     
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