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Using a B20A for B20/VTEC?

Discussion in 'Engine Building' started by B16RacerN2NR, Nov 12, 2005.

  1. B16RacerN2NR

    B16RacerN2NR Working Hard VIP

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    Just wondering if you could do a B20/VTEC with the B20's out of an 89 prelude. This kid (he's a friend, of a friend's, friend...hope that made sense. Anyway...) wants to either do a swap because the motor is blown or go VTEC using his existing block. I've put together quite a few motors so i'm not an idiot, but I can't, for the life of me, find any info on using the B20A block or swapping in a GSR or some shit into his Prelude. I hear rumors that the block is not usable for going VTEC so i'm looking for the answeres as to why. Also, could I just put a B20B or Z into this car if going VTEC is a no no?
     
  2. phunky.buddha

    phunky.buddha Admin with a big stick Admin VIP

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    You CAN use a B20A for a VTEC conversion, but it's generally not recommended. It doesn't go together the same way as a B20B or B20Z conversion, the stroke is really long, and those engines have a reputation for being unreliable.

    You definitely can put a more up to date B series engine in there if you want.
     
  3. B16RacerN2NR

    B16RacerN2NR Working Hard VIP

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    What problems would I run into using the B20A block as opposed to using an LS or B20B/Z block, beside unreliability?

    As far as putting a more up to date motor in, the mounts, along with the brackets, look completely different but I figure they can be bolted to what ever motor he chooses to go with. That being said, has anyone ever tried it?
     
  4. phunky.buddha

    phunky.buddha Admin with a big stick Admin VIP

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    You're looking at a really long stroke without very long rods, plus a history of people killing those engines at high rpm. There have been a good number of B16 head conversions on the B20A block though. Look for a site called "ludespeed.com" or something like that.

    Yes, people have put newer B blocks into those Preludes before. I don't have links, but they're not hard to find.
     
  5. hotrex

    hotrex Senior Member

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    yeah, it requires an adapter plate or some shit.,

    b20a5 is the bastard b series motor, nothing from other b series fits, the r/s ratio is like 1.52 and its just overall terrible.
    you will most certainly blow it up reving it and forget turbo
    you want a b20b or b20z. end of discussion

    and even those, if you plan to turbo it, have terribly weak sleeves.

    on a side note, ive seen b16a swaps in oldeer preludes.
     
  6. B16RacerN2NR

    B16RacerN2NR Working Hard VIP

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    Well, the block says B20A on it. No following number after the letter. So I wouldn't have to worry about that a5 block :)
    I've actually convinced him earlier today that he'd be better off letting me put a B20Z in it. So he said that would be fine with him. That way when he gets some more funds later on, he can go VTEC on a much better block. Thanks for the help guys.

    EDIT: I tried searching for a few prelude sites and I found one in particular (preludepower.com) and mainly all the threads I searched for say that "NO" other B Series engines fit and that going with an H22 would be even easier [​IMG] IDK, i'm getting mixed emotions about what fits and what doesn't. Anyone have a better site for the 3rd gen preludes because I can't find shit worth a damn. Thanks
     
  7. VTECin5th

    VTECin5th Administrator

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    PreludePower is the best prelude forum there is.
    They are OS, i used to be there like 4 years ago when i had my 3rd gen.
    They are correct, no B series engine will easily drop in, and it is easier and more cost efficient to put an h22 in there, and wider support.
    You CAN use a b20a or b20a5 or b20a7 block with the b16 head, like Cal said.
    It does require a bit of work.
    Find the site archiver, or googled cache site of LudeSpeed.com (Tom) and see pics of it done.
    He made some INCREDIBLE numbers with a blown headgasket (low spot on block)
    I think it was like 130TQ @ 3,xxx rpm not even to the power band yet.
    The b20a(5)(7) motor likes to break though,again as Cal mentioned...
    I read on PP a long time ago that the t-belt spacing was offset by so many tenths of an inch or something, and that's why alot of 3rd gen preludes snap t-belts like nothin.
    I'm sure the motor CAN be built to be 'quality' but it's not a 'good' idea.
    I still want to build a b20aV just to do it... and maybe someday i will.
    Tom from LudeSpeed was selling a bolt on b16 head kit for around $2,000, came with EVERYTHING YOU NEEDED including the oil pan parts and such... he no longer sells the kits though.
    The main problem you will run into is you need to drill the head in _i think_ two places for oil passages, and you need to have the head bolt holes widened up for the bolt pattern to match up correctly.
    Then you have to make your own headgasket, since none will work, you HAVE to make it.
    Putting a b16 into a 3rd gen prelude would be like swapping a ZC motor into an accord, it's possible, but the lack of torque will just make you want to shit your pants.
    Accordingly, putting a b20/z in there would be a waste of money/time/effort also.
    It's specs are close to the b20a, but the b20a is alot cheaper to work with.
    That is why there is alot more h22+3rd gen support, it's the only swap that makes sense.
    It's not that much work really from what i see/read/hear, but i haven't personally done a h22 into a 3rd gen, nor could i afford to.
    I think total cost rounds to $4k for the h22 in there.
    I would love to see someone with a bunch of hookups to do a b20aV and dyno it.
    I also read on PP that b16 pistons/parts fit in the b20a(5/7) without modification, and something something, smaller stroke somethin somethin higher revving somethin somethin getting safer and easier etc.
    There's a TON of good info there, and a lot of people who will help you out.
    But don't make a request for the b20aVTEC, they just tell you to "ask xxx" or "search for xxx"
    I searched and found 100,000 n00bs saying "b16 head fit on here?" just gettin flamed away.
    A cheaper alternative is the h23 into there, and still makes decent power for the price ($600-$900) similarly priced b20b/z which will end up costing you more in the end most likely, for less stock form power.
     
  8. B16RacerN2NR

    B16RacerN2NR Working Hard VIP

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    I just couldn't find anything of what you told me on that website. So I guess i'm assed out on putting a B20B or Z in his car because this kid is working on a tight budget. He has $700 to spend at most and I know i'm not swapping an H22 in thier for that price. HMotors has the B20B's for $650 and that would of been perfect. He really didn't want to rebuild his old motor but now he pretty much doesn't have a choice.

    Thanks again guys.
     
  9. VTECin5th

    VTECin5th Administrator

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    No problem, but why rebuild it?
    Go to a junkyard and buy one.
    The first one i paid $300 or somethin, the second one we bought from a junkyard, we paid $80 for the whole longblock.
     
  10. B16RacerN2NR

    B16RacerN2NR Working Hard VIP

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    because if I rebuild it I know it'll last more than a week. I really don't trust junk yard motors. You never know what kind of condition it's in and neither do the guys who run the junk yards. Especially when trying to find a motor that is known for it's unreliability.
     
  11. pissedoffsol

    pissedoffsol RETIRED

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    even if you get the 20a blcok for free, you're not getting this working with 700 bucks. no way in hell.

    IMO, the b20a is worth as much as a paper weight.
     
  12. B16RacerN2NR

    B16RacerN2NR Working Hard VIP

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    why not?
    Micro polish the crank=$40
    Bearings=$50 (and they are ACL's too)
    Block Hone= Free (I got a friend who will do it)
    Complete Gasket Kit=$250 (including head gasket)
    Oil Pump=Free (kid already has it)
    Water Pump=$65
    Resurface Flywheel=$25
    New Clutch Kit=$125 (stock OEM replacement)
    All Fluids= $60 or so

    Total=$615... He has already put away the $400 for my labor, that's including pulling the motor out, rebuilding it, then putting it back in. $400 is cheap but he's a good friend of one of my friend's so I hooked him up.
     
  13. hotrex

    hotrex Senior Member

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    turbo the b20a5. if it is just a b20a stamp, its still worthless

    i would slap a junkyard kit on there., and see what happens. for 700 bucks, your not getting much.,

    end of discussion, although u could build a solid junkyard setup for under 500 if you know what the hell your doing, but b20a vtec, is a waste of time,

    that whole prelude is a waste of time,
     
  14. pissedoffsol

    pissedoffsol RETIRED

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    ok, but thats your bottom end...

    you haven't even STARTED the vtec portion of it.

    so once again, you're wasting your time and money on it.

    do it if you want... but there's a reason no one uses them...
     
  15. B16RacerN2NR

    B16RacerN2NR Working Hard VIP

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    oh, I thought I stated that he wasn't going to go VTEC any more. Sorry lol... he pretty much just wants his car up and running again so i'm just going to rebuild the motor.
     
  16. hotrex

    hotrex Senior Member

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    prob cheaper to find one local in a yard.
     
  17. B16RacerN2NR

    B16RacerN2NR Working Hard VIP

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    yeah but like i said before, they are unreliable as it is so a junk yard motor doesn't give me good peace of mind. This way, if I rebuild it, I know it'll last at least a month. Getting a motor from the junk yard, it could last you 3 hours, it could last you 10 years, I just don't want to take that chance.
     
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