BBC retro-fit pushrod ?
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BBC retro-fit pushrod ?

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    Default BBC retro-fit pushrod ?

    I have a Mark IV BBC and am going to install a solid roller cam in it. I have Crane solid roller lifters and CompCams roller rockers. Am I going to need different pushrods to go with a roller cam? Thanks!

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    If the cam core (and lobe base circle) is based on a stock dia., you shouldn't need different lengths based on the lifter change. However, it's easy enough, and always a good idea to check and make sure.
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    Quote Originally Posted by steelcomp View Post
    If the cam core (and lobe base circle) is based on a stock dia., you shouldn't need different lengths based on the lifter change. However, it's easy enough, and always a good idea to check and make sure.
    SHAME ON YOU STEEL!!! Gettin soft after that thread with hotbo? Of course you are going to need new pusrods. Not because of the lifters or rockers, but because they weren't the right length to start with. Read this WHOLE site, until your eyes bleed and your head explodes and then you tell me if you think if they need to be checked.
    http://www.mid-lift.com/What-is-ML.htm
    If it doesn't make sense to you or you have a hard time understanding it, ask steel, he loves explaining the whole concept



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    Quote Originally Posted by gn7 View Post
    SHAME ON YOU STEEL!!! Gettin soft after that thread with hotbo? Of course you are going to need new pusrods. Not because of the lifters or rockers, but because they weren't the right length to start with. Read this WHOLE site, until your eyes bleed and your head explodes and then you tell me if you think if they need to be checked.
    http://www.mid-lift.com/What-is-ML.htm
    If it doesn't make sense to you or you have a hard time understanding it, ask steel, he loves explaining the whole concept
    Sorry, should have qualified my answer with "if they were right to start with"...my guess is that three out of five "professionally" built engines have the wrong length pr's, anyway...that's kind of a given. Don't you know better than to declare the obvious, you old fart?
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    I just love putting that link up, it makes my Tylinol stock soar and I figure it will give him something to read for the next day or two.



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    Got it, thanks!

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    Quote Originally Posted by gn7 View Post
    SHAME ON YOU STEEL!!! Gettin soft after that thread with hotbo? Of course you are going to need new pusrods. Not because of the lifters or rockers, but because they weren't the right length to start with. Read this WHOLE site, until your eyes bleed and your head explodes and then you tell me if you think if they need to be checked.
    http://www.mid-lift.com/What-is-ML.htm
    If it doesn't make sense to you or you have a hard time understanding it, ask steel, he loves explaining the whole concept

    what the hell does this mean the thread with hotbo

    just playin boys,i think yes you will need different pushrods.if the ones you have are not good 1 piece pushrods most certainly,get new ones.if you have good ones just check and see.

    hope it works out for ya,travis{a.k.a. hotbo} one sorry dog i guess

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    This is what a eng. builder did for me. What is wrong with this pic?
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    Quote Originally Posted by hotbo View Post
    what the hell does this mean the thread with hotbo

    just playin boys,i think yes you will need different pushrods.if the ones you have are not good 1 piece pushrods most certainly,get new ones.if you have good ones just check and see.

    hope it works out for ya,travis{a.k.a. hotbo} one sorry dog i guess
    Yep, I'd be more concerned with the strength of your current pushrods as much as the length, speacially if you rods are the stockers or your last cam was a flat tappet



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    Quote Originally Posted by Tombstone View Post
    This is what a eng. builder did for me. What is wrong with this pic?
    Looks like pushrod length is to long!

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    Quote Originally Posted by Tombstone View Post
    This is what a eng. builder did for me. What is wrong with this pic?
    If you have to run a long valve to get the proper installed height for some spring applications, with proper geometry the rocker is going to run a little towards the outside edge of the valve. Yours looks a little extreme, but not knowing your setup it could simply be too long of a pushrod. The longer the valve, the closer the tip gets to the rocker stud. If you shorten up the pushrod to make the rocker in the center of the valve tip you can end up with horrible geometry, and if you get the geometry perfect you CAN end up with what you have and wear the guides. I try to find a happy medium.
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    there is only ONE CORRECT PUSHROD LENGTH for any given set up, and it's actually pretty simple to explain, not as easy to achieve. When your cam is at half the net lift(lash set) a line thru the pivot fulcrum to the nose roller is 90* to the valve stem. Once you have done this a few times it gets pretty easy, but most just throw up their hands and whip out some plastic thingy or some wack method and call it good. As BD stated as the valve gets longer the valve tip moves closer to the rocker stud, and this some that you just have to except, trying to get it back to the center may end up with really bad geometery



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    Quote Originally Posted by gn7 View Post
    Yep, I'd be more concerned with the strength of your current pushrods as much as the length, speacially if you rods are the stockers or your last cam was a flat tappet
    Yep, totally agree, big roller cam and stout springs that go with it deserve some good pushrods. Of course, always check length as well...


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    Default push rods

    Always check length. Usually some difference. Can even change after a valve job/ head resurface... Have countless sets of pushrods that are now the wrong size

    On this current motor, T&D has a specific checker. Needed to shim the shaft mounts. With the Big Duke heads, needs three different lengths.

    Jerry

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