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b20 block gaurd, or block gaurds in general

Discussion in 'Engine Building' started by killercannible, Apr 23, 2006.

  1. killercannible

    killercannible Senior Member

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    I know that b20's are notoriously weaker than other b motors because the cylinders are bored out to 84mm and there fore are much thinner. I have seen a friend of mines get blown up, although that was caused by a :mrgreen: miss shift from 3rd to 2nd at 8grand. So my question is blockgaurds, are they worth it, i can see how they would substantially strengthen the cylinder wall but also think that because they are so cheap in price and not widely talked about that mabey they are not worth it at all. Tell me what you guys think, interested in a b20 vtec turbo with stock pistons and rods. :mrgreen:
     
  2. MikeBergy

    MikeBergy Blah blah blah....

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    check out the diy blockguard in the articles section. Probably every bit as effective as a commercially made one, and cheaper. I'd use one if I were building a budget turbo setup. I don't have any prior experience with them, but the principle they work off is good.

    edited for syntax. :)
     
  3. Eye Heart Boost

    Eye Heart Boost Member

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    I will not run a block gaurd... ever. I've seen too many motors have their cylinders go out of round due to them.. and in my humble opinion, if you're going to do a block gaurd, just spend the extra $50 and get an actual gaurd. The DIY method makes me want to puke in my mouth.
     
  4. phunky.buddha

    phunky.buddha Admin with a big stick Admin VIP

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    By the way... B20s are not "notoriously weaker". They're not made of glass. +98735 for the number of times I've said it. The B20 reputation suffers horribly from the Honda-Tech hype machine.
     
  5. MikeBergy

    MikeBergy Blah blah blah....

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    And by people who said "I was making 2342353464687455 hp on my b20 vtec, and it broke!!! This block is weak!"
     
  6. phunky.buddha

    phunky.buddha Admin with a big stick Admin VIP

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    w3rd

    Mine was awesome for 45k miles, and then I did something stupid and melted a piston. The block looked perfect on disassembly.
     
  7. GSRCRXsi

    GSRCRXsi Super Moderator Moderator VIP

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    just figured id chime in here since mike #3 mentioned the diy blockguard. i would advise against this. hotrex did not update on the subject on this site, however he did on honda-tech. basically he cracked all 4 sleeves, not a result of tuning or anything, but a result in thermal expansion differences beween the devcon and the block.

    see for yourself... http://honda-tech.com/zerothread?id=1444721&page=21

    some people on there claim it was tuning, but if you look at the thermal conductivity numbers of devcon and the iron/aluminum sleeve, you will see that the value for the devcon is MUCH lower thus acting like an insulator. coupled with the fact that coolant cannot physically touch the sleeve to properly cool it.

    IMO hotrex should come here and post his results of his ruined motor (not only did he crack all 4 sleeves but he ruined the pstons as well). and possibly even take down the write up as it clearly contributed to the downfall of this motor. he will be quick to blame it on something else, but its clear to me that the devcon is the problem.
     
  8. MikeBergy

    MikeBergy Blah blah blah....

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    Sux, I thought it was a pliable epoxy...no bueno to two different types of rigid material with two different material thermal properties.
     
  9. GSRCRXsi

    GSRCRXsi Super Moderator Moderator VIP

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    if it was pliable it wouldnt do anything, lol
     
  10. phunky.buddha

    phunky.buddha Admin with a big stick Admin VIP

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    Hmm.

    Very true. I totally didn't think about that... and I used to research block guard material all the time too.

    :werd:
     
  11. killercannible

    killercannible Senior Member

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    I am happy that you could tell me about do it yourself but how about the commercially available ones, usefull or not?
     
  12. phunky.buddha

    phunky.buddha Admin with a big stick Admin VIP

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    They can be, as long as you don't warp the sleeve bore when you install them.
     
  13. 97CTR

    97CTR Senior Member

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    I would never run a blockgaurd, however if you do end up doing so.... Make sure that it has plenty of coolant holes, have it welded in by a machine shop and get the cylinders bored to oversize (81.25 or 81.5mm)
     
  14. MikeBergy

    MikeBergy Blah blah blah....

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    Well, not like jelly pliable. I just thought maybe it was like a very hard rubber. Vibrational dampening was what I was thinking of, lol. Damping can actually help a lot in certain situations.
     
  15. brian11to1

    brian11to1 Senior Member

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    the article needs to be taken down. very misleading
     
  16. GSRCIVICTN

    GSRCIVICTN Lost in a sea of rednecks

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    Thank God someone said what I have been thinking. Everyone ranted and raved about this rigged up method like it was the best thing since sliced bread. I never understood how it's benefits could possibly out-weigh the potential damage to the engine. I hate to hear that some of you may have f*cked your engines, but I'm glad I'm not crazy.
     
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