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R

Ronno6

Member
Much to my surprise:
Not all screw in rocker arm studs are created equal!
The machine shop supplied me with PBM 7/16" screw in rocker arm studs.
Laying a straight edge across the installed studs revealed an unsettling picture.
The studs were so far out of concentric that there were gaps of about .025" at adjacent studs!
I have not been able to find a concentricity spec for these studs, but I measure .012" or worse!
I have installed ARP studs, guaranteed to be concentric within .005".
Laying the straight edge across them now gives a whole different picture.
Worst gap across the entire 8 studs is barely .003"
Most are touching the straight edge..........
I am smiling !!
 
yeah, most of the imported crap has quality control issues and the PBM stuff ,
and most other import parts are rather well known for that
I once used a timing set a buddy bought, for $11 at a auto parts store close out bin,
a SBC timing gear/chain set imported from India,
that had the tdc index vs the key-way location, 11 degrees off of true tdc,
if you used that timing set with the dot-to-dot cam install vs,
using a degree wheel install, it would be off index significantly,
we found out how off index it was using a degree wheel and dial indicator cam install
 
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