t&d rocker arm geometry help needed
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t&d rocker arm geometry help needed

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    senior member turbo wog's Avatar
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    Default t&d rocker arm geometry help needed

    i installed the t&d's according to the instructions & that did not work. the valve stems are too long. the heads have a raised port & that put the rocker on the outside edge of the valve. i had to (not shim) the assembly in order to get the rocker onto the center of the valve stem. this caused the geometry of the pushrod to look kind-of screwed. the exaust pushrod is 16* off of being 90* . & the intake @ 19* off from being 90*. the stud mounted rocker came in A angle but it had a deep pocket to recieve it at any steep angle. the t&d's dont. it looks like it is wrong. & i am thinking of taking this back off. here are some pics.I need some good opinions from experienced builders. my opinion is that this set-up sucks for my heads & i want my $$ back..i know t&d's are supposed to be real good but for this application? thanks in advance
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    Senior Member Hass828's Avatar
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    Quote Originally Posted by turbo wog View Post
    i installed the t&d's according to the instructions & that did not work. the valve stems are too long. the heads have a raised port & that put the rocker on the outside edge of the valve. i had to (not shim) the assembly in order to get the rocker onto the center of the valve stem. this caused the geometry of the pushrod to look kind-of screwed. the exaust pushrod is 16* off of being 90* . & the intake @ 19* off from being 90*. the stud mounted rocker came in A angle but it had a deep pocket to recieve it at any steep angle. the t&d's dont. it looks like it is wrong. & i am thinking of taking this back off. here are some pics.I need some good opinions from experienced builders. my opinion is that this set-up sucks for my heads & i want my $$ back..i know t&d's are supposed to be real good but for this application? thanks in advance
    What brand of heads are those? It appears that as you have said, with that long of valve that there is a geometry problem and those rockers may not work for you. With the correct length of pushrod your going to run off the edge of the valve. Steelcomp would be the man to talk to about this. He's dealt with simular issues on here before. I believe he went to a set of ford rocker arms to cure it.
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    Default geometry

    Did you set it up with adjustable pushrods, and then order the length you need?

    On my Brodix heads with T&D, it takes three different lengths.

    Jerry

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    Did you disassemble a rocker, remove a spring and use the gage from the shaft to the valve stem?

    There shouldnt be a problem if you shimmed them using that method.
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    steelcomp was here
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    I'm not following your first post completely.
    First, what heds are they?
    Second, when you say the rockers are off 16*/19* from 90*, do you mean at mid lift? What part of the rocker are you referring to for this angle?
    To recap: The imaginary line that passes through the center of the trunnion and center of the roller tip needs to be at 90* to the valve at mid lift.
    It's a mistake to try to get the roller tip centered on the valve as a means of establishing proper geometry. With extra long valves the pattern will typically be on the outer 1/3 of the valve. Any more than that, to me, is not acceptable.
    Those look like Brodix conventional heads, so if you have the right part number from T&D they should fit.

    This comment makes no sense to me at all:

    the stud mounted rocker came in A angle but it had a deep pocket to recieve it at any steep angle. the t&d's dont.
    Last edited by scott foxwell; 05-23-2011 at 07:35 AM.
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    I am currently setting up a new set of T&D's on a new set of Brodix BB 4 xtra heads. You didn't state whether you used the gauge that T&D supplies with the set, but it's critical to getting geometry correct with them. Pushrod length is merely a function of the diameter of the cam and final height of the rocker.

    That being said, the set I am working on needed to lower the exhaust stands about .055", due to using some Ferrea super alloy valves that come in only a few lengths. They were about that much shorter than the "stock" Brodix valves, but necessary for this engine since it will be turbo charged. The owner and I chose to have that much removed from the heads, but it could have come off the bottom of the rocker stands to give the same results. The intake stands will need a couple of shims, but needed to have a little machining to allow the stands to sit flush onto the head.

    I elected not to pull a rocker apart,, didn't want to hurt one of the tiny snap rings, but instead measured the shaft diameter and used a substitute .625" diameter shaft to measure height. *** Note that T&D also gives instructions that the checker tool needs to be adjusted according to cam lift ***

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    I noticed in your second pic that there is quite an angle on the push rod to the rocker seat. If this is what you are talking about you will have to get radius end (for the rocker end only) push rods. Some push rod manufacturers will ask if you are using shaft rockers.
    Most of the time if you change rocker types on any engine it will require different push rods.

    Fred

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    Quote Originally Posted by steelcomp View Post
    It's a mistake to try to get the roller tip centered on the valve as a means of establishing proper geometry.
    Steel, I swear, this is by far and away the biggest misconception in setting up rocker geometery. This one misconception is probably responsible for more poorly set up rockers than any one single thing. Who ever came up with line of BS should be kicked in the nutz.

    As long as the roller isn't in jeopardy of riding off the edge of the valve, stop worrying about the rollers location on the valve tip. It will only lead down a path of bad geometry trying to get that one useless thing lined up. If you chase that, you can't help but blow it where it really counts.

    Try putting it back the way they sent it to you, with the roller off center, and check you rocker geometry again.

    On some heads, with long enough valves, the only way the roller can be in the center of the valve stem is if they actually relocate the rocker back towards the intake manifold. Crower, in their stud rockers does just that in a effort to get the roller back on center. But its was a waste of time and money. Being off center on the top of a 11/32 valve amount squat in side load.
    Raising or lowering the rocker to relocate the roller is a HUGE mistake. The location of the roller IS NOT play into proper geometry. EVER.
    The spring is what causes guide wear, not the location of the roller pushing on the valve. The heavier the spring, the faster the wear. The spring side loads the valve, not the roller.



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    Paul
    Read andFollow the instructions !! what Barry (Obnoxious 001) and Ron (infomaniac) are saying is correct . you may have to shim or machine off some material off the head .

    Also if you are using Lash caps that extra hight has to be figured in .

    the gage supplied with the rockers is for .750 lift , so whatever your cam is >follow the instructions .

    Mine work fine , on Brodix 2-extras ... Eric
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    Doing a set right now that are going to take .250 to get em right.
    Quote Originally Posted by gn7 View Post
    It would be a balmy 85* in Steel's shop if he would move a little faster

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    the last set of Brodix heads I did ended up having to shim up the stands quite a bit,
    due to a smaller cam, and longer valves- the shims were not cheap from T&D either!

    you can kinda see in the picture that the stands are shimmed up quie a bit- but these are the
    cheaper type T&D's with the individual stands..... prevous settup was .700+ lift with a stock length
    valve- now setup for 650 lift with .100 long valves......ignore the date, this was 09
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    senior member turbo wog's Avatar
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    Quote Originally Posted by billet racing View Post
    Did you set it up with adjustable pushrods, and then order the length you need?

    On my Brodix heads with T&D, it takes three different lengths.

    Jerry
    ?three?where would the third size go?&yes,i cut a pushrod & slid fuel line over it to the right lenght & then measured it

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    Quote Originally Posted by Hass828 View Post
    What brand of heads are those? It appears that as you have said, with that long of valve that there is a geometry problem and those rockers may not work for you. With the correct length of pushrod your going to run off the edge of the valve. Steelcomp would be the man to talk to about this. He's dealt with simular issues on here before. I believe he went to a set of ford rocker arms to cure it.
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    Quote Originally Posted by Infomaniac View Post
    Did you disassemble a rocker, remove a spring and use the gage from the shaft to the valve stem?

    There shouldnt be a problem if you shimmed them using that method.
    yes & it was too far out to the outside of the stem. the machine shop thought it looked better without the shims as far as the roller on the valve stem goes. t& d said the big chiefs have a pretty steep angle for the push rod also. so as long as it goes in i shoukld be fine.

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