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  1. #1
    wide the f*** open sloLs1's Avatar
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    ANOTHER LS1 piston question!

    i promise its the last one!

    ok, so Ls1's have flat top pistons, correct?? and the "stock" c/r on a 98 ls1 is 10.19.... MY QUESTION IS, what would the c/r be if a set of -4cc dished pistons were installed??? can you correct that with milling the heads??


    thank you.... and yes maybe i shoulda just had my engine built somewhere so i dont have soooo many friggin questions!
    '95 saturn < v8 GONE!
    '09 avalanche < tow rig
    '05 ion < DD
    '63 chevy ll < new project
    Some girls do want an 8 second ride

  2. #2
    Ol' School BAD LS1's Avatar
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    Quote Originally Posted by sloLs1 View Post
    i promise its the last one!

    ok, so Ls1's have flat top pistons, correct?? and the "stock" c/r on a 98 ls1 is 10.19.... MY QUESTION IS, what would the c/r be if a set of -4cc dished pistons were installed??? can you correct that with milling the heads??


    thank you.... and yes maybe i shoulda just had my engine built somewhere so i dont have soooo many friggin questions!
    http://www.csgnetwork.com/compcalc.html

    10.1:1 cr, flat top mahle cast piston, yes.

    plug in 3.898" Bore, 3.622 stroke, 3.910 head gasket diameter, .047" head gasket thickness, 66cc combo chambers, -4 cc dish, and .000 deck clearance. = ABOUT 9.9 CR

    so you either need 64cc ls6 heads OR mill your current heads but then will need to figure out the proper pushrod length since that will change. or run a .040" head gasket or thinner, then re check your push rod length needed. these changes noted here will get it back to about 10.1 again.

    id go with taking some cc out of the heads and a thinner gasket to get te cr to 10.3 or so, that will boost low end torque and nitrous love compression!
    Last edited by BAD LS1; 01-26-2009 at 08:34 PM.
    2012 Cruze ECO M6 - Crystal Red- Just a little more boost than stock!
    2001 Camaro SS - Rallye Red - In process.

  3. #3
    wide the f*** open sloLs1's Avatar
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    Quote Originally Posted by BAD LS1 View Post
    http://www.csgnetwork.com/compcalc.html

    10.1:1 cr, flat top mahle cast piston, yes.

    plug in 3.898" Bore, 3.622 stroke, 3.910 head gasket diameter, .047" head gasket thickness, 66cc combo chambers, -4 cc dish, and .000 deck clearance. = ABOUT 9.9 CR

    so you either need 64cc ls6 heads OR mill your current heads but then will need to figure out the proper pushrod length since that will change. or run a .040" head gasket or thinner, then re check your push rod length needed. these changes noted here will get it back to about 10.1 again.

    id go with taking some cc out of the heads and a thinner gasket to get te cr to 10.3 or so, that will boost low end torque and nitrous love compression!

    so about those heads you have?!?!!?



    ok and heres the piston specs on the one i found....

    Mahle Motorsport Forged 346 cid LS1 Flat-Top Piston Set: 3.898" Bore, 3.622" Stroke, 6.098" Rod Length, .945" Wrist Pins, 1.314" CH, -4cc Dish; Wrist Pins and Piston Rings Included
    Last edited by sloLs1; 01-26-2009 at 09:03 PM.
    '95 saturn < v8 GONE!
    '09 avalanche < tow rig
    '05 ion < DD
    '63 chevy ll < new project
    Some girls do want an 8 second ride

  4. #4
    Ol' School BAD LS1's Avatar
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    Quote Originally Posted by sloLs1 View Post
    so about those heads you have?!?!!?



    ok and heres the piston specs on the one i found....

    Mahle Motorsport Forged 346 cid LS1 Flat-Top Piston Set: 3.898" Bore, 3.622" Stroke, 6.098" Rod Length, .945" Wrist Pins, 1.314" CH, -4cc Dish; Wrist Pins and Piston Rings Included
    pretty much as close to a stock replacment dimension wise as you can get. forged mahle's are good units and they come with some kinda heat/wear resistant coating too.
    2012 Cruze ECO M6 - Crystal Red- Just a little more boost than stock!
    2001 Camaro SS - Rallye Red - In process.

  5. #5
    wide the f*** open sloLs1's Avatar
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    Quote Originally Posted by BAD LS1 View Post
    pretty much as close to a stock replacment dimension wise as you can get. forged mahle's are good units and they come with some kinda heat/wear resistant coating too.
    yea... but i also see domed pistons as well?!?! i just dont know what will work right with what im building! i would perfer a 10.5:1 motor.... because of the cam and the way it'll be driven! and of course the shot of the good stuff! If this was a gen 1 sbc or a saturn engine id have no problem finding all the correct info for this! and im sooo darn anttzzz to order parts!
    '95 saturn < v8 GONE!
    '09 avalanche < tow rig
    '05 ion < DD
    '63 chevy ll < new project
    Some girls do want an 8 second ride

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