Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

6.0" con rods. . .will they work

Discussion in 'The Garage' started by BowtieRed, Aug 3, 2004.

  1. BowtieRed

    BowtieRed 1/2 ton status Author

    Joined:
    Dec 31, 2002
    Posts:
    1,776
    Likes Received:
    0
    Location:
    Winston-Salem, NC
    6.0\" con rods. . .will they work

    i want to up my compression on my project motor. it's a gm goodwrench 350, can i simply use 6.0" rods to get the compression i want or will that cause valves clearance issues?
     
  2. Z3PR

    Z3PR Banned

    Joined:
    Mar 30, 2002
    Posts:
    19,217
    Likes Received:
    0
    Location:
    Everywhere
    Re: 6.0\" con rods. . .will they work

    To do it right, order new pistons for desired compression with what ever cc heads you are useing.
     
  3. m j

    m j 1/2 ton status

    Joined:
    Dec 28, 2001
    Posts:
    4,606
    Likes Received:
    0
    Re: 6.0\" con rods. . .will they work

    6.0 - 5.7 = 0.3
    if your piston is 0.3 in the hole at TDC then you could do it.
    if your piston is 0.3 in the hole at TDC you have some problems.
     
  4. BowtieRed

    BowtieRed 1/2 ton status Author

    Joined:
    Dec 31, 2002
    Posts:
    1,776
    Likes Received:
    0
    Location:
    Winston-Salem, NC
    Re: 6.0\" con rods. . .will they work

    except i don't want to bore the motor any if possible, maybe i'll have to, idk. so does anybody know for a fact that they will or will not work?
     
  5. BowtieRed

    BowtieRed 1/2 ton status Author

    Joined:
    Dec 31, 2002
    Posts:
    1,776
    Likes Received:
    0
    Location:
    Winston-Salem, NC
    Re: 6.0\" con rods. . .will they work

    what all would i need for a roller camshaft? just the retrofit lifters?
     
  6. CaveBlazin

    CaveBlazin 1/2 ton status Premium Member

    Joined:
    May 21, 2002
    Posts:
    1,348
    Likes Received:
    1
    Location:
    Middle TN
    Re: 6.0\" con rods. . .will they work

    I'll tell you everything you need to know if you sell me your tires /forums/images/graemlins/thinking.gif
     
  7. BowtieRed

    BowtieRed 1/2 ton status Author

    Joined:
    Dec 31, 2002
    Posts:
    1,776
    Likes Received:
    0
    Location:
    Winston-Salem, NC
    Re: 6.0\" con rods. . .will they work

    how about the whole truck no engine for $1000 /forums/images/graemlins/grin.gif
     
  8. Beast388

    Beast388 1/2 ton status

    Joined:
    Nov 6, 2001
    Posts:
    3,039
    Likes Received:
    0
    Location:
    Clinton, IA USA
    Re: 6.0\" con rods. . .will they work

    Increasing rod length has nothing to do with compression ratio. The only way to increase CR is by decreasing the combustion chamber volume or by increasing the stroke.

    If you changed nothing else on your engine, but added 6.0" rods, the motor would not turn over. You would be pushing the piston out past the deck of the block by 0.3" like mj refered to. When a 6.0" rod is used, it requires a new set of pistons with a reduced compression height. In other words, the distance from the top of the pistion to the centerline of the wrist pin is decreased by 0.3" to account for the rod that is 0.3" longer.

    If you want to increase compression, get pistions with less dish, change the heads for a set with a smaller chamber volume or both. /forums/images/graemlins/waytogo.gif
     
  9. BowtieRed

    BowtieRed 1/2 ton status Author

    Joined:
    Dec 31, 2002
    Posts:
    1,776
    Likes Received:
    0
    Location:
    Winston-Salem, NC
    Re: 6.0\" con rods. . .will they work

    ok, now what about the roller camshaft?
     
  10. Z3PR

    Z3PR Banned

    Joined:
    Mar 30, 2002
    Posts:
    19,217
    Likes Received:
    0
    Location:
    Everywhere
    Re: 6.0\" con rods. . .will they work

    [ QUOTE ]
    except i don't want to bore the motor any if possible, maybe i'll have to, idk. so does anybody know for a fact that they will or will not work?

    [/ QUOTE ]Why would you need too bore ??? I'm talking going from a dish piston to a flat top or even dome type piston. Depending on what cc your heads are, would determen what piston you would need for what compression you want. Boreing the cly is not needed unless the engine has alot of miles and you're getting blow by.
     
  11. BowtieRed

    BowtieRed 1/2 ton status Author

    Joined:
    Dec 31, 2002
    Posts:
    1,776
    Likes Received:
    0
    Location:
    Winston-Salem, NC
    Re: 6.0\" con rods. . .will they work

    i can't find any 4.000" bore 10:1 pistons, there's the problem. they are all 4.030" that i can find.
     
  12. Z3PR

    Z3PR Banned

    Joined:
    Mar 30, 2002
    Posts:
    19,217
    Likes Received:
    0
    Location:
    Everywhere
    Re: 6.0\" con rods. . .will they work

    Where are you looking ??? If all else fails, call Jeg's 1-800-345-4545. They have alot more then whats listed on thier website and in thier catalog.
     
  13. 84_Chevy_K10

    84_Chevy_K10 Banned

    Joined:
    May 30, 2001
    Posts:
    17,669
    Likes Received:
    0
    Location:
    IL, USA
    Re: 6.0\" con rods. . .will they work

    [ QUOTE ]
    If you want to increase compression, get pistions with less dish, change the heads for a set with a smaller chamber volume or both. /forums/images/graemlins/waytogo.gif

    [/ QUOTE ]

    Or deck the block, which is cheaper than both of those and goes a long way to helping your quench distance.
     
  14. Beast388

    Beast388 1/2 ton status

    Joined:
    Nov 6, 2001
    Posts:
    3,039
    Likes Received:
    0
    Location:
    Clinton, IA USA
    Re: 6.0\" con rods. . .will they work

    [ QUOTE ]
    [ QUOTE ]
    If you want to increase compression, get pistions with less dish, change the heads for a set with a smaller chamber volume or both. /forums/images/graemlins/waytogo.gif

    [/ QUOTE ]

    Or deck the block, which is cheaper than both of those and goes a long way to helping your quench distance.

    [/ QUOTE ]

    Uh-huh....
    [ QUOTE ]
    The only way to increase CR is by decreasing the combustion chamber volume or by increasing the stroke.


    [/ QUOTE ]

    You can only deck the block so far before the quench distance is too tight. Depending on the tolerances in his current motor, he may not be able to deck the block much at all.

    What is the quench distance on your motor Tim? /forums/images/graemlins/thinking.gif
     
  15. big83chevy4x4

    big83chevy4x4 3/4 ton status

    Joined:
    Mar 22, 2002
    Posts:
    6,587
    Likes Received:
    0
    Location:
    Sheridan, Michigan
    Re: 6.0\" con rods. . .will they work

    or have the heads machined, it'll probably cost the same, have the same result, but wil be easier cause you only need to have 2 40lbs heads instead of one 200lbs block. you would need to take more material off the heads than the block to get the same result.

    you can only go so far with the block. you can not go past the pistons, because then the piston would hit the head and it'll do some damage. but the heads you can go alot farther.
     
  16. CyberSniper

    CyberSniper 1/2 ton status Premium Member

    Joined:
    Apr 21, 2003
    Posts:
    2,257
    Likes Received:
    5
    Location:
    Chelsea, MI
    Re: 6.0\" con rods. . .will they work

    [ QUOTE ]
    i can't find any 4.000" bore 10:1 pistons, there's the problem. they are all 4.030" that i can find.

    [/ QUOTE ]

    Everyone makes them.

    Speed-pro (Federal Mogul) makes some decent hypoeutectic flat tops with 6.1cc reliefs for about $120. So far, that's all I've run in all my motors.

    EDIT: they make them in different piston pin heights... sometimes you have to cross over into Keith Black pistons though... same crap, different name.
     
  17. SUBFAN

    SUBFAN 1/2 ton status

    Joined:
    Mar 23, 2003
    Posts:
    2,334
    Likes Received:
    0
    Location:
    Davenport, Ia
    Re: 6.0\" con rods. . .will they work

    Please get a book that describes basic engine theory and performance modifications. A bad machine shop might take advantage of you. I would hate to see you spend a lot of money on something that plain does not work, or throws a rod through the pan on the break in.

    Going to a roller cam is not that simple. Is that Goodwrench motor a roller block already?

    What kind of compression are you looking for? What is the compression now? What fuel do you want to run, and what is the objective of this motor, street/some play, or all play all out?

    What I am getting at, if you are looking for a 1/2 point increase, you are not going to really notice the difference vs. the cost/hassle involved....
     
  18. m j

    m j 1/2 ton status

    Joined:
    Dec 28, 2001
    Posts:
    4,606
    Likes Received:
    0
    Re: 6.0\" con rods. . .will they work

    not much to gain in a roller lifter for the $$$
     
  19. BowtieRed

    BowtieRed 1/2 ton status Author

    Joined:
    Dec 31, 2002
    Posts:
    1,776
    Likes Received:
    0
    Location:
    Winston-Salem, NC
    Re: 6.0\" con rods. . .will they work

    going roller, i know the deal with it now, roller cam, and retro fit roller lifts, lotta money, but TONS of gain, atleast according to desktop dyno. i'm lookin at 10:1 compression and run 93 octane and octane booster. i want to go full roller, this will be a street/strip/mud motor. so high rpm. i built the engine i want on desktop dyno, now it's a matter of $$, i got 466hp and 449ft lbs.
     
  20. 84_Chevy_K10

    84_Chevy_K10 Banned

    Joined:
    May 30, 2001
    Posts:
    17,669
    Likes Received:
    0
    Location:
    IL, USA
    Re: 6.0\" con rods. . .will they work

    [ QUOTE ]
    You can only deck the block so far before the quench distance is too tight. Depending on the tolerances in his current motor, he may not be able to deck the block much at all.

    What is the quench distance on your motor Tim? /forums/images/graemlins/thinking.gif

    [/ QUOTE ]

    Not true, a Chevy can be decked to zero and running regular Fel-Pro perma torque gaskets gives you .042", which is right in the ideal of .039-.045.

    As to what my quench distance is, I believe in the .065" range as the engine has composite gaskets and AFIAK not been decked although it has been rebuilt. I blew up the engine I built for this rig and haven't had the funds to build another yet, but when I do, it will be a 383 with 5.7 rods, balanced, decked to zero, with the fel pro perma-torques and aftermarket heads.

    If ya decked to zero and tried running steel shims I'd say that's a no go, but decking to zero or +.002 or so and running composites and your choice of piston/chamber volume is the way to go IMO.
     

Share This Page