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Whats the diff between Y8 andZ6?

Discussion in 'Engine Building' started by All Show, Sep 5, 2003.

  1. All Show

    All Show Member

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    I just need to know what the differnces between the Z6 head and the Y8 head if any. I have a D16Y7 and am shopping of a VTEC head and would like to know. I have searched the old forms and found nothing on this topic. Thanks in advance.
     
  2. racecarl

    racecarl Member

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    besides that the z6 is ODB1 and the y8 is ODB2... not much is different. they can both be installed on your y7 block pretty easily. however, if you decide to go with the z6 head, you will have to run a new oil jet and convert the ignition to odb1 but it shouldn't be that big of a deal. personally, i suggest using the y8 because: a) you're more likely to find one with similar miles to your engine and, B) z6 heads on y7 blocks have a reputation of overheating. it is rumored that the odb1 setups put out a few more ponies, but i wouldn't worry about it. you're getting vtec and ditching that crappy intake mani either way. good luck, and post your results.
     
  3. All Show

    All Show Member

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    I would like to buy the Y8 but they are a bit harder to come by and a bit more expensive. I all ready installed a 98 auto Ex intake manifold so I am part way there. I was just thinking if the the Z6 was the same I would buy that. I knew the VTEC solenoid and switch was the same but I wasn't sure about the distributer, and the 2 sensor beside where the distributer goes. I am converting to OBD 1 so that might make it easier again. Are the Y7, Y8 and the Z6 distributers all the same? If not what distributers will go with what heads when I convert to OBD1?
     
  4. MaliWho97

    MaliWho97 Senior Member

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    You can always get an OBD-2 to OBD-1 adapter harness and eather a P28 or an upgraded hondata computer if you get the Y8 head..... Here are the differences that I was told... The Y8 is often confused as the better head because of the port size.... It is a little larger than the Z6, but, the Z6 flows better. A friend took both heads in stock form and put them on a flow bench and the Z6 flowed better. The Y8 would be easier to install though, due to the oil and overheating issues. Also, on the intake manifolds, heres a tip. Find a stock intake manifold off of an H22, and have it port matched to the head, as well as ported out a little bit. It flows just as good or better than the new Skunk2 Intake manifolds when you do that! If you are going all motor, slap on a 64-66mm Throttle Body, you should be set!!!
     
  5. All Show

    All Show Member

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    Thanks for the great info, looks like I will go with the Y8. I wish i wouldn't have installed that Y8 intake manifold and throttel body. With the H22 manifold can I use my stock injectors and fuel rail or will I need to upgrade whose as well?
     
  6. pissedoffsol

    pissedoffsol RETIRED

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    actually, they have several differences.

    Y8 uses a thinner head gasket which gives it more cimpression, has a better Intake Manifold, has a larger queche area due to square combustion chambers which gives more power potential, is plugged obd2a or obd2b depending on the year, and has a better/stronger tranny.

    This running of a new oil jet, needs to be done regardless of which head you decide to use.

    Depending on local laws, running an older head, or any head swap for that matter may be illegal.

    I suggest running the y8 head for ease of wiring
     
  7. MaliWho97

    MaliWho97 Senior Member

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    Thats very true, I actually went to a friends house yesterday where we took both heads side by side and studied them, and the ports on the Y8's intake plenum inside of the port is set back further and has a much larger opening..... As for the OBD2, the Y8 is the swap to go with....
     
  8. All Show

    All Show Member

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    Luck for me in Canada we don't have strict emission laws (yet) but on the flip side we can't drive our sport compacts for 4 months of the year cause of the snow. I will spend the extra money and buy the Y8 just because I don't want something that is going to overheat and it will be easier to wire.

    As far as changing the oil jet I am not sure what you mean. Is the oil jets in the Y7's different that the Y8's? I know if you are installing a Z6 or Y8 head on a CRX Si block you need to run an exterenal oil line to the head but it was my understanding that this was not needed for my swap.

    Does anyone know of any website with step by step instructions with pics which shows how to do this swap?
     
  9. cxjon

    cxjon Senior Member

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    mn is that same way
     
  10. 97hatch

    97hatch ?

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    ok im confused i didnt think that you hadt to run oil line if you had a y7 block and also could you just stick the obd2 distributer on the z6 head also how hard is it to get the h series manifold to fit and also can i do the same with a b or f series thanks.
     
  11. All Show

    All Show Member

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    Can anyone answers these questions that me and 97hatch have?
     
  12. All Show

    All Show Member

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    Someone must know.
     
  13. pissedoffsol

    pissedoffsol RETIRED

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    i just found a good geocities site... i can't verify if any of this is accurate, but it looks good to me.

    So everyonce in a while there is someone out there asking the difference between the 2 So on Friday I picked up a 1998 Y8 for $100 to answer this Ongoing question(engines kinda like Joe_R ZC, an accident broke the cam gear and the pistons contacted the valves in #3 cylinder.)

    Number 1 difference on the out side Cast aluminum oil pan(better oil cooling.....Aluminum tranfers heat better than steel, just try to cut an
    aluminum block this a torch, No worky!)

    Number 2 they decided to move the oil dipstick next to the timing belt and it is made of plastic no more burning your hand and trying to get it back into the damn hole in between the manifold.

    Number 3 Crank sensor?(under the Timing belt cover by the crank) and what seems to be an additional coolant sensor and other add ons that I could not tell you what they are in the back of the block.

    Number 4 what I think may be a bad design is the fuel return line is about 1 inch away from the input line.

    Number 5 the size of the plentum on the Intake manifold is about 2 times the size with slightly longer runners(can you say more TORQUE).

    Number 6 If sombody has one of the manuals for this engine I would like to know the name of the sensor bolted on to the fuel rail

    Number 7 water pipe on the back of the block....Aluminum tube better cooling again.

    Number 8 cooling lines in different places...gonna make it difficult for me to put 98 head on a 95 block.

    Number 9 Aluminum A/C bracket 1/2 the weight of a Z6 cast steel bracket

    Ok now for inside the engine

    Number 10 The Square Combustion chamber!!!Ahh 9.6:1 CR instead of 9.1:1

    Number 11 I also noticed that there was no Oil control jet when I pulled the head of course I have never pulled a Z6 head yet and looked at the block.

    Number 12 very odd because people who do the Mini-Me Sohc vtec head on a A6 block should have a consern here. I noticed that the valves are MUCH BIGGER on a Y8 head. and the pistons look nothing like the A6 pistons. Piston to valve clearance may be a consern for Y8 heads on A6 blocks little cresent shape on Y8 pistons are spaced farther apart than on a A6 piston.

    Number 13 I also notice they have changed the lifters under the valve cover for Vtec Operation(New and improved???Dunno)

    Number 14 Cam gear itself is 1/2 the weight of the Z6( its like a 5 star Cast Wheel not a solid piece of steel. Can you say reduced reciprical mass)
     
  14. All Show

    All Show Member

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    That awesome, thanks a lot for the info it is much appreciated.
     
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