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Hypothetical engine build... input please!

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    Hypothetical engine build... input please!

    Ok I've been tossing this around in my head for a few weeks now and want some input.

    Lets say I'm working on a turbo build.
    F22Ax block, forged internals, all that good stuff to maintain and keep it reliable for moderate to high boost.
    Block will be bored out to 86mm to bump displacement up to a proper 2.2L and because of the new pistons.

    Now that the block is board out to 86mm, the bottom of the F22Ax head's combustion chamber is still at the 85mm, thus causing this sort of situation:



    Not ideal since the bore of the block and the head differ in size, not a lot, but it's enough that I don't like it nor would proceed with the build.


    So what options are there? Obviously one option is to machine the head so that it matches the bore of the block... but I was thinking of another solution.

    Why not use the head of a F23A5? It's SOHC, Non-VTEC, AND already has a head that matches it's 86mm bore. Thus the F23A5 head is ready to go with no machining needed to match the 86mm bore of the F22Ax block.


    Yes I know that particular head supposedly doesn't flow as well, but I don't think it's a big issue since it will be turboed.

    I'm not one to Frankenstein my way through a build, far from it, but I am looking at every possible alternative to this issue.

    Input? Thoughts?
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    #2
    When you get your head work done just pull a mill of the diameter. Problem solved.
    '93 H22A 5SPD SE - MRT - DIY-Turbo Sizing

    Comment


      #3
      Yes I know, that is one option of the two that I've already stated.

      I think what I am wondering is would it be worth my time/effort/money to even bother with matching the head to the bore. I've ran across this several times and even machinist and companies who do this for a living say it's not worth the bother.
      Click Image for CB7Tuner.com Beanies, Decals, & Keychains!

      Comment


        #4
        the machine shop near me will not actually bore a block out unless proof shown that the head will match the bore.also when i bring my block to get bored and honed they take the head with it for no charge to match the block.

        my new turbo build

        Comment


          #5
          Dammit! I need to find a different shop.
          My local shop, even though they do an awesome job, wants to charge an additional $70 to do the head which in the scheme of things is a drop in the bucket.... but brings me around to the whole idea of even considering the F23A5 head which I have found for less... free actually. I literally just go pick it up and it's mine.

          The cheapskate in me is kicking my ass on this. Because $70 is $70... but using the damn F23 head is Frankensteining the build which I don't like at all...


          I think talking this out loud has pretty much helped me decide which way to go.
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          Comment


            #6
            Yeah but then you'll need an intake manifold.
            My Members' Ride Thread - It's a marathon build, not a sprint. But keep me honest on the update frequency!

            Comment


              #7
              Originally posted by Jarrett
              Yeah but then you'll need an intake manifold.
              Why?

              Pay the $70 and get on with your life....it's that simple. I mean you're anti-frank, so you should know that if you build it right the first time, than no problems(or very little) should come your way.
              '94 JDM H22A: 178whp 146wtq

              Originally posted by deevergote
              If you say double dutch rudder, i'm banning you...

              Comment


                #8
                You said it yourself, it doesnt flow as well. What you would be doing is create a "bottleneck" by putting that head on hurting power. With your theoretical BUILT engine that would be moving backwards.

                Comment


                  #9
                  The head doesn't flow as well true, but I don't know about creating a "bottleneck". He can always have the head ported later if he believes it's hurting his output that much.
                  '94 JDM H22A: 178whp 146wtq

                  Originally posted by deevergote
                  If you say double dutch rudder, i'm banning you...

                  Comment


                    #10
                    Since the F23 head will match the bore size, it's not THAT big of a deal. I don't know how the oil ports match up (I know ports need to be blocked off with the H22 head, and I don't like that.)

                    The F23A1 head flows better than the F22b1 head, from what I've been told (I haven't confirmed that myself.) With boost, you can definitely make more power than you'll care to put down in a street car with even a stock F23A1 head... so I wouldn't worry.

                    Now, the thing to consider is... $70 to machine your current head to match.
                    What is an F23A1 head going to cost you? The head itself, matching gaskets, VTEC-compatible ECU, a properly sized timing belt, intake manifold and throttle body, any sensors associated with the head, accessories mounted to the head... Using an F23A1 head COULD result in an even higher cost than machining the F22A head.






                    Comment


                      #11
                      Not true actually. there are a few flow sheets out there that show the F23A flows just as well as a stock PT3 head (F22A1-6). Actually flows better at low lift. And they seemed to have finally cleaned up the F22A exhaust flow issues with the F23 as well.

                      F23A5 (PAA)
                      Lift --- Int. --- Exh.
                      0.1" - 85 - 79
                      0.2" - 171 - 141
                      0.3" - 232 - 176
                      0.4" - 258 - 190
                      0.5" - 273 - 196

                      F22A (PT3)
                      Lift - Int. - Exh.
                      0.1" - 82 - 44
                      0.2" - 165 - 108
                      0.3" - 219 - 143
                      0.4" - 251 - 156
                      0.5" - 275 - 163

                      Now if you are looking to get some porting done. The F22A has a lot more potential than the F23. The F23 suffers from the same port geometry issues and wet port exhaust design as the F22B1/2. This does not allow for a good straight through flow design. This is where the F22A starts to really pull through. It has 0-0-0-0 evenly spaced ports and it does not have wet wall exhaust ports. this allows for more room to shape the ports accordingly.
                      Last edited by GhostAccord; 03-01-2012, 11:59 AM.
                      MR Thread
                      GhostAccord 2.4L Blog

                      by Chappy, on Flickr

                      Comment


                        #12
                        In stock form, I don't doubt it. The F22A head really doesn't flow all that well without proper porting. People forget that the "F22A superiority" thing comes AFTER proper work is done!

                        When boost is involved, even the most poorly flowing F series heads will be capable of making more power than anyone needs on the street.






                        Comment


                          #13
                          Originally posted by Joey GT-R View Post
                          Why?

                          Pay the $70 and get on with your life....it's that simple. I mean you're anti-frank, so you should know that if you build it right the first time, than no problems(or very little) should come your way.
                          My suggestion on the intake manifold was in regard to getting the F23 head.


                          To me this seems like it's not even up for discussion. Have the head milled then radius the combustion chambers. $70 is not that big of a price considering its a major step toward building the engine correctly.
                          My Members' Ride Thread - It's a marathon build, not a sprint. But keep me honest on the update frequency!

                          Comment


                            #14
                            Now keep in mind I'm talking about the F23A5 head from the 1998-2002 Honda Accord DX and value package. No VTEC shit to deal with.


                            Since I can get the head for free, I may snag it and tinker around and see how well (or poorly) everything lines up.
                            And yes I will need to consider everything else involved with using the F23A5 head like deev pointed out. That alone may result in one huge ass headache.


                            GhostAccord, thanks for the info on the flow of the head.
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                            Comment


                              #15
                              One day I'm gonna build an F and show you pansies how it's done....lol
                              '94 JDM H22A: 178whp 146wtq

                              Originally posted by deevergote
                              If you say double dutch rudder, i'm banning you...

                              Comment

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