Does size matter
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Does size matter

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    Member ltr450's Avatar
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    Default Does size matter

    what are you guys running for push rod sizes.. 3/8, 7/16,5/8 you hear alot about cam size, but not alot about the push rods themselfs. I've got a mild build 461 bbc,with roller rockers and solid flat tappet a 640 lift

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    Senior Member tkriley13's Avatar
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    Oh yeah it does just ask _ _ _ _!!! hahahahahaha I can tell you where to buy a set of $400.00 ones??? I think you know what I`m talking about... Pete I think for either of us we just need to go to MANTON in Lake Elsinore and let them tell us what to run.

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    steelcomp was here
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    IMO pushrods can't be "too big". There is far more strength in cross sectional area than there is in wall thickness, ie: I;d rather run a thinner wall 7/16 than a heavy wall 3/8. In your case, depending on rpm, a quality 3/8 x .083 wall should be plenty. I spec a minimum 7/16 pushrod for any solid roller engine I build now.
    If God is your co-pilot, change seats!
    Acts 2:38, the perfect answer to the perfect question.

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    Quote Originally Posted by tkriley13 View Post
    Oh yeah it does just ask _ _ _ _!!! hahahahahaha I can tell you where to buy a set of $400.00 ones??? I think you know what I`m talking about... Pete I think for either of us we just need to go to MANTON in Lake Elsinore and let them tell us what to run.
    just trying to get some info from the big dogs..because i'm sure they have been there and done that..

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    Senior Member tkriley13's Avatar
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    Pete - You can have the 3/8 x .083 ones that we changed out at the Elsinore race... I dont need a full set (that arent ment for my motor) for spares!!! I have 2 int & 2 exh extra I just found.. that should be all we need to run the magic number this next season... This sunday you ready to put the work shop back together? Then we need to tear that pig apart....

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    Member ltr450's Avatar
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    Quote Originally Posted by tkriley13 View Post
    Pete - You can have the 3/8 x .083 ones that we changed out at the Elsinore race... I dont need a full set (that arent ment for my motor) for spares!!! I have 2 int & 2 exh extra I just found.. that should be all we need to run the magic number this next season... This sunday you ready to put the work shop back together? Then we need to tear that pig apart....
    thanks i'll cheak them out but i think there going to be a little off. Since your set up is for a roller. mine measures out at 8.550 intake and 9.500 exhaust ..but lets get that thing dialed in, we got some racing to do

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    Senior Member ol guy's Avatar
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    Quote Originally Posted by tkriley13 View Post
    Oh yeah it does just ask _ _ _ _!!! hahahahahaha I can tell you where to buy a set of $400.00 ones??? I think you know what I`m talking about... Pete I think for either of us we just need to go to MANTON in Lake Elsinore and let them tell us what to run.
    DITTO. It does not take a 7/16 push rod. more along the lines of geometry. I personally run the lightest push rod I can and make sure it is not getting so far out of angle that it will become a pretzel. I will also admit I am not a big lift cam fan! I spring the head/valve combo to be able to handle the intended rpm of the engine. Cstraub would probably be the best to give the best advice. MLAO Mark

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    Senior Member tkriley13's Avatar
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    Quote Originally Posted by ltr450 View Post
    thanks i'll cheak them out but i think there going to be a little off. Since your set up is for a roller. mine measures out at 8.550 intake and 9.500 exhaust ..but lets get that thing dialed in, we got some racing to do
    Remember that is why I needed the special 400.00 dollar ones since it was for a roller and those were from the old motor before roller...seat pressure crap I guess... I`m about done with that cam though it better wake up with the stuff we`re doing this year!

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    Senior Member jimclauss's Avatar
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    Quote Originally Posted by ltr450 View Post
    what are you guys running for push rod sizes.. 3/8, 7/16,5/8 you hear alot about cam size, but not alot about the push rods themselfs. I've got a mild build 461 bbc,with roller rockers and solid flat tappet a 640 lift
    you can get away with almost anything with that 5/8 pushrod what the hell is that ???? lets go for a .840 and do away with the lifter
    Last edited by jimclauss; 01-30-2012 at 07:14 PM.

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    Quote Originally Posted by steelcomp View Post
    IMO pushrods can't be "too big". There is far more strength in cross sectional area than there is in wall thickness, ie: I;d rather run a thinner wall 7/16 than a heavy wall 3/8. In your case, depending on rpm, a quality 3/8 x .083 wall should be plenty. I spec a minimum 7/16 pushrod for any solid roller engine I build now.
    Never use them and I don,t have a problem

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    steelcomp was here
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    Quote Originally Posted by jimclauss View Post
    Never use them and I don,t have a problem
    Not that you're aware of.
    If God is your co-pilot, change seats!
    Acts 2:38, the perfect answer to the perfect question.

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    steelcomp was here
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    Quote Originally Posted by ol guy View Post
    DITTO. It does not take a 7/16 push rod. more along the lines of geometry. I personally run the lightest push rod I can and make sure it is not getting so far out of angle that it will become a pretzel. I will also admit I am not a big lift cam fan! I spring the head/valve combo to be able to handle the intended rpm of the engine. Cstraub would probably be the best to give the best advice. MLAO Mark
    Weight on the lifter side of the rocker is far less important than rigidity, and how do you change the pushrod angle other than off-set rockers and lifters? Are you saying you go to that extent? Shaft rockers and light pushrods? How do you know how much spring pressure you need?
    If God is your co-pilot, change seats!
    Acts 2:38, the perfect answer to the perfect question.

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    I feel this is more dictated by spring pressure and engine rpm and even cam profiles/dynamics. OR call manton.

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    steelcomp was here
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    Quote Originally Posted by havasubyou View Post
    I feel this is more dictated by spring pressure and engine rpm and even cam profiles/dynamics. OR call manton.
    Cam profiles and rpm...yes; spring pressure, no. Spring pressure does two things...it keeps the lifter on the nose of the cam, and keeps the valve from bouncing when it closes. In a lot of cases, engines are running way more open pressure than necessary to help control lofting, which is caused by pushrod flex. We already have a valve spring, we don't need the pushrod acting as another one. With bigger pushrods and getting the lofting under control, you may actually need less open spring pressure to control the lifter.
    If God is your co-pilot, change seats!
    Acts 2:38, the perfect answer to the perfect question.

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