Measure push rod lenght on stock rocker arm design
April 9th, 2018, 05:26 AM
#1
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Join Date: May 2015
Location: Innsbruck / Austria
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Measure push rod lenght on stock rocker arm design
Hello,
when I change my camshaft and have a different lift and change to factory style rocker arms with a 1:6 ratio, how do i measure the push rod lenght. There is a lot of information out there about how to adjust with roller rocker arms but I did not find any information on how to do that on factory style rocker arms?
My preferred rocker arms see picture.
Thanks for your help.
Daniel
when I change my camshaft and have a different lift and change to factory style rocker arms with a 1:6 ratio, how do i measure the push rod lenght. There is a lot of information out there about how to adjust with roller rocker arms but I did not find any information on how to do that on factory style rocker arms?
My preferred rocker arms see picture.
Thanks for your help.
Daniel
April 9th, 2018, 09:36 AM
#2
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Join Date: Apr 2012
Location: Bradenton, FL
Posts: 1,467
https://www.summitracing.com/parts/c...UaAr5SEALw_wcB
and a soft spring to replace the valve spring that is on there now as this tool isn't that strong. Any spring will work as long as you can compress it with your fingers and it won't depress the lifter.
and a soft spring to replace the valve spring that is on there now as this tool isn't that strong. Any spring will work as long as you can compress it with your fingers and it won't depress the lifter.
April 9th, 2018, 09:38 AM
#3
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Join Date: Sep 2011
Location: Plano, TX
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http://lmgtfy.com/?q=how+to+measure+pushrod+length
Same as with any other setup.
Get adjustable measuring pushrods.
Install one cylinder's valvetrain with the adjustable pushrods. Some of them you have to assemble in place - just depends on which type and if it has locking nuts, whether or not the locking nuts hit the head.
Adjust the pushrods and turn over the engine until you get the best geometry possible.
Once you have it set, pull and measure the pushrods.
If you're paranoid then you can check a bunch of cylinders, but that's not necessary. Olds tend to use the same pushrod length for intake and exhaust.
Note that you may not be able to get a good valve tip sweep. It depends on the cam - if the base circle is too different than the stock, then it just won't work well without also moving the rockers. Aftermarket cams get higher lift by cutting the base circle.
Same as with any other setup.
Get adjustable measuring pushrods.
Install one cylinder's valvetrain with the adjustable pushrods. Some of them you have to assemble in place - just depends on which type and if it has locking nuts, whether or not the locking nuts hit the head.
Adjust the pushrods and turn over the engine until you get the best geometry possible.
Once you have it set, pull and measure the pushrods.
If you're paranoid then you can check a bunch of cylinders, but that's not necessary. Olds tend to use the same pushrod length for intake and exhaust.
Note that you may not be able to get a good valve tip sweep. It depends on the cam - if the base circle is too different than the stock, then it just won't work well without also moving the rockers. Aftermarket cams get higher lift by cutting the base circle.
April 9th, 2018, 01:30 PM
#5
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Join Date: May 2015
Location: Innsbruck / Austria
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So with a "mid radical" change it will work much better with Roller Rockers? Will change from Stock 330cui (250 hp) camshaft to edelbrock performer rpm. I am asking because i am Not sure how to find Perfect Rocker arm Geometrie - because Coloring the valve Stam and Check if Roller Push the middle will Not work on stock Style 1,6 Ratio Rockers. Thank you
April 9th, 2018, 01:55 PM
#6
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Join Date: Mar 2011
Posts: 558
I would just put the lifter on the the base circle then with an adjustable pushrod, find zero lash (until there is no play up and down between the lifter and the rocker arm).
Then measure the adjustable push rod length for zero lash and buy pushrods .050” longer.
The geometry is already set with your valve stem height. You just need to find the correct size pushrod for correct preload.
Then measure the adjustable push rod length for zero lash and buy pushrods .050” longer.
The geometry is already set with your valve stem height. You just need to find the correct size pushrod for correct preload.
Last edited by VinMichael; April 9th, 2018 at 02:09 PM.
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