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need some help

Discussion in 'Engine Building' started by jamesA, Jan 2, 2005.

  1. jamesA

    jamesA Well-Known Member VIP

    Likes Received:
    Aug 10, 2003
    to figure out exactly what I need to get.

    First I decided to go ahead with an ls/vtec setup instead of a stroker kit. I see tons of ls/vtec dyno graphs with a shit load more torque than a b16 ever made, and it'll be easier to hit 200 whp all motor with a larger motor. (obviously)

    So I plan on getting and obdII B18b block and boring it over, but I'm not sure exactly how much I need to fit the pistons I was looking at... more questions on that later.

    First, I do know I want to support IB Spec so I'm going to get internals through him. I want to go all motor but I want to leave room for a 50 shot of nitrous just in case... Wil and I were talking through AIM and he told me that he's using H beam rods and he likes them, but IB Spec specificially says I Beam is best for all motor applications right here.

    As for the pistons, I want to get some IB Spec, but I don't see anything specially built for the LS/VTEC, so would I want to get some for an overbored GSR block seeing as how they're the same 81 mm bore?

    Which Pistons?

    With that in mind, back to the block. The pistons in the previous link that I know I want are the .5 MM overbore, but I have no idea on what kind of dome I'd want to get, I don't want to make this an interference engine but I'd like to be able to put 12.5:1 compression down on the 5.394 length rods.

    For the bore size: in. x 25.4 = MM

    So roughly I'd want a .020 overbore, right? That comes up to .508 mm. Does that sound right for ring clearances? or no?

    As for the head I know i'm getting some S2S2 cams, but has anyone had any experiences with the IB spec springs and retainers?

    Second to last picture, Spring/Retainer kit.
  2. phunky.buddha

    phunky.buddha Admin with a big stick Admin VIP

    Likes Received:
    Sep 30, 2002
    Dallas / Fort Worth, TX
    If you're going to go high compression all motor, you'll have an interference engine no matter what. The only difference between the pistons for the GSR and the LS/VTEC are how the compressions are calculated. They're interchangeable- just recalculate compression based on the dome size, your combustion chamber size, and your total displacement.

    The I beam rods are what I'm using. Either one will work fine for all motor. Jeff's I beam rods are lighter than the H beam Eagles though, so you'll free up some rotating mass and get more torque with the I beams.

    A 50 shot of juice properly tuned on a high compression all motor setup will be fine. Just tune it right!

    The block needs to be match bored to your pistons, so just get .5mm oversize pistons, then send everything out to a good machine shop to have it all matched up.
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