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"stock" pistons to raise comp --B20b??

Discussion in 'Engine Building' started by 78civic, Sep 28, 2009.

  1. 78civic

    78civic Junior Member

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    What are some "stock" honda pistons to raise the compression of the CRV/B20b block??

    And Which head would be better.. The B18a or the stock B20b? From what I've seen, the B20's ports are lots bigger! But that doesn't mean it flows well.
    I'm looking at a N/A motor for now, so If I can get it around 9.0-9.3 would suffice I think.

    E
     
  2. INJEN78

    INJEN78 HS LEGEND

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    for a b20 there really isnt stock pistons..the cylinders of a b20 are bigger than any b18(obviously) so the high compression p30 pistons wont fit..
     
  3. reikoshea

    reikoshea HS Troll...And Mod Moderator VIP

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    werd. most b-series engines have an 81mm bore. b20b is 84mm.
     
  4. SlushboxTeggy

    SlushboxTeggy It's only stupid if it doesn't work VIP

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    Yup, plus a B20 doesn't have iron sleeves. Big loss.

    B18 head will makes more power, but I'm not sure if that is because of the flow, camshafts, or a combination of other stuff.
     
  5. INJEN78

    INJEN78 HS LEGEND

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    do the b18 head with b20 cams..the b20 cams in the b18 are like gsr cams in a b16
     
  6. D15Beater

    D15Beater HNFTuning

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    For pistons you have a choice of the P3F B20b piston which you have or the PHK from the B20z2 same bore but a higher compression OEM piston.

    The B20 head is the same casting as the LS(b18) but with different intake manifolds.

    HYBRID B20 Tech
     
  7. 78civic

    78civic Junior Member

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    Thanks Guys.
    Slushbox: I thought that it did?? I can't imagine that it's just Aluminum..

    INjen: Thanks, Back in the day I used a place called "Colt cams" They will regrind in a way that creates more 'swirl' velocity by opening up one of the intake vlaves slightly earlier. It's pricy but If I can sell some parts maybe!!

    D15beater, I tore it down last night and it (b20b) had two burnt ex valves in 1-2. But I did notice that the B20b head looked to have bigger intake ports..? And I read through another link that the 20b needs to "breath well"
    From experience, The older Hondas like to have HIGH VELOCITY to the intake valve so I'm kinda stuck thinking that I should use a 20b intake welded to the last portion of the B18 or just cut apart, hog out, port match,and weld back together the b18 intake. (I sure wish that Extrude honing wasn't that expensive!)
    The exhaust ports look to be the same.. HHhhmmm, Maybe a good porting of the exhaust would help. It looked that one could use bigger Ex valves too. But that would add up $$.
    I'll try and get some comparison pics of it tonight. Even the combustion chambers between the B20/B18

    OR I'll just put some 40mm Del Orto side-drafts on it.. (I wonder what type of mileage I'd get with those?)

    About the pistons, I think I remember reading that even the B20Z pistons were .030 in the hole.. ( wonder if it would be worth it to mill the block down .02+ or Zero even and take it up with adjustable gears..?)
    Boy, one could really make the engine think its got lots more compression by milling to zero, advancing the intake by 8+ or so, retarding the ex by 6 or so, and claying the vlaves.
    I wonder how much movement the gears will let you get away with.
    It could be a pain to dial in the dizzy though.

    Thanks again E
     
  8. 78civic

    78civic Junior Member

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    Thanks Guys.
    Slushbox: I thought that it did?? I can't imagine that it's just Aluminum..

    INjen: Thanks, Back in the day I used a place called "Colt cams" They will regrind in a way that creates more 'swirl' velocity by opening up one of the intake vlaves slightly earlier. It's pricy but If I can sell some parts maybe!!

    D15beater, I tore it down last night and it (b20b) had two burnt ex valves in 1-2. But I did notice that the B20b head looked to have bigger intake ports..? And I read through another link that the 20b needs to "breath well"
    From experience, The older Hondas like to have HIGH VELOCITY to the intake valve so I'm kinda stuck thinking that I should use a 20b intake welded to the last portion of the B18 or just cut apart, hog out, port match,and weld back together the b18 intake. (I sure wish that Extrude honing wasn't that expensive!)
    The exhaust ports look to be the same.. HHhhmmm, Maybe a good porting of the exhaust would help. It looked that one could use bigger Ex valves too. But that would add up $$.
    I'll try and get some comparison pics of it tonight. Even the combustion chambers between the B20/B18

    OR I'll just put some 40mm Del Orto side-drafts on it.. (I wonder what type of mileage I'd get with those?)

    About the pistons, I think I remember reading that even the B20Z pistons were .030 in the hole.. ( wonder if it would be worth it to mill the block down .02+ or Zero even and take it up with adjustable gears..?)
    Boy, one could really make the engine think its got lots more compression by milling to zero, advancing the intake by 8+ or so, retarding the ex by 6 or so, and claying the vlaves.
    I wonder how much movement the gears will let you get away with.
    It could be a pain to dial in the dizzy though.

    Thanks again E
     
  9. INJEN78

    INJEN78 HS LEGEND

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    the walls of the b20 are actually weak and i think are only alumi..
    but id imagine if you put a b18 head on it it would have more compression..then with the b20 cams it would have some more pep
     
  10. boostin4fun

    boostin4fun Boosted ls/vtec ohh yeah!

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    The b20 does have iron liners. You are right though about the blocks being somewhat weak. Here is a picture of a b20 block I got off of endyn's site. If you zoom in you can see that there is a iron liner.

    [​IMG]
     
  11. reikoshea

    reikoshea HS Troll...And Mod Moderator VIP

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    Yeah, definitely not aluminum sleeves. The issue people have with b20's is the fact that they are the same casting as an LS with an 84mm bore (compared to 81mm on the LS).

    That loss in 3mm makes people think (and usually rightly so) that the block is weaker than the LS.
     
  12. D15Beater

    D15Beater HNFTuning

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    If this is the case and the B20 head has bigger intake ports then would this be a upgrade for LS guys. Regaurdless the ignitial casting is still the same between the two.

    You could go through all that work fabbing up the b20 intake manifold but wouldnt it be easier to port the LS intake manifold to match the B20 intake ports. I remember seeing a picture of a B20 and LS intake beside each other and the B20's intake ports were noticably bigger. I tried to find that picture this morning when I saw this post but was unsuccessful. id like to see the comparison pics though, post them up.
     
  13. 78civic

    78civic Junior Member

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    AAaahh CRAP! I don't get much of anything done with this crappy shift..
    Just had to vent. Well I hadn't pulled the 18 head but the layered ex gasket fits the same on both heads, and this little plastic int gasket is the same also..?? I might be able to pull the 18 head later tonight.
    Then I can measure the liners also to maybe put an end to q's.. I'll try to measure from the water-jacket edge to edge (the whole floating bore), and then the thickness of each wall for each block.

    Boostin, I like your pic with the cylinder 'stabilizers'. That ran across my mind to apply that also. I also thought of the plates that go in the top of the block but wondered if they compensate for the little 'bump' that they have for extra material around the stud bosses?

    Back in the day, I would bore a EJ 1300 block out to a 1500 and (73mm-75mm) never had a problem, Just didn't boost it. Just a webber. I even have a 1200EB that I bored out to a 1500 too! (I need to finish that one by now, donchathink)

    D15beater I think I saw it on "Bens resource page" The intake ports looked to be around 1/4" larger! Here at work, I'm not set up for Email and don't know how one would contact him to see what the casting #s he had.

    If I don't run out of time, I'll try and measure the cams for a comparisson to.

    E
     
  14. INJEN78

    INJEN78 HS LEGEND

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    there is a diff. in cams..i know for a fact..
     
  15. LS_VTEC

    LS_VTEC you get the BRAKE

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    True story. :thumbsup:
     
  16. SlushboxTeggy

    SlushboxTeggy It's only stupid if it doesn't work VIP

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    Shit. My fault. For whatever reason, I thought they had composite walls like the H22.
     
    Last edited: Oct 1, 2009
  17. reikoshea

    reikoshea HS Troll...And Mod Moderator VIP

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    lol, i said the same thing years ago and calesta corrected me. if there's one thing i KNOW mike knows more than me about........its ICBMs.........and b20s. i dont make the same mistake twice :D
     
  18. efhondakid

    efhondakid My name is Byron. VIP

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    Why not put in a set of flat bottom valves to bump compression?

    :EDIT: They dont make them for the LS.
     
    Last edited: Oct 1, 2009
  19. 78civic

    78civic Junior Member

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    EF-kid: I thought the exact same thing when looking at the heads side/side.They have some major dishing in them.. On my old heads, I used the 'tulip' shaped ones. At the time, that was the only way to get flat headed ones. (well, that's what the machinist told me)

    I don't have a 3rd party hosting so If someone would like pics to post them for me I'd be glad to shoot them to ya.. I took some pics and measurements last night and came up with some interesting things.

    WARNING: this is between MY B20B4 and MY B18a1 so if you don't like it.. poopoo on you!
    Here goes.. Granted there may have been some carbon/crap in the way, but maybe .004-.10??

    -------------------------------B20b4----------------B18a1----------------
    Bore thickness @same places,---.295----------------.257------------------
    both blocks.-------------------.310----------------.270------------------
    -------------------------------.290----------------.265------------------

    Siamese webbing @2/3------------.247---------------.360------------------
    sleeve thickness----------------.130---------------.130------------------

    I'm thinking that these people saying the B20's have weak walls might be using tooo much boost therefore generating too much heat, warping the cyl just enough. (That's why I like the epoxied studs thru the block wall)
    Looking at around .030-.040 divided by 2 isn't that much less thickness. The liners looked to be the same. Just what they are "in" for the B18a1 is ever-so-thicker. I mean my hair is .007! In addition, Looking at the thickness of the blocks from outer wall to outer wall, the B20 does look thicker. My dial caliper doesn't go that far out.
    I think I might look into "O"ringing the head for future boost applications. IT COULDN'T HURT

    The heads appear to have the same combustion shape/size. I didn't have time to look for my valve spring compressor to measure the seats but they looked close if not the same.
    I did notice differences in water passages at different points around the combustion chambers and in the front of the head. Probably to make up for the thinner water passages around the liners. (probably bigger water passages around the c/chamber to cool it more.
    I remember reading a passage from Smokey Unick how he was saying the GM 400 block wouldn't reach its' full potential because of the siamese bores didn't have the cooling as did the smaller motors and at racing temps, they distorted causing improper ring sealing.

    Anywho, If someone would like pics to post let me know. I have grown to hate computers and don't want to smash another one.. $$

    E

    Aaarrg, I had it all nice and aligned up.. then i hit submit
     
    Last edited: Oct 1, 2009
  20. D15Beater

    D15Beater HNFTuning

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    Good info man, what about the intake ports? Different or same?
     
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