Generation IV External Engine - l92 rocker arms
charged 434
04-21-2010, 08:00 PM
building a 427. hydrolic roller, f1c procharger. turning motor to 7000. lift on cam will not be bigger than 650 lift. mast l-92 heads. will the stock rocker arms work, or what do i need
thanks
The stock rockers definitely go to 7000 RPM reliably. GM puts them on the LS7 which has a 7100 RPM redline so they are good to go IMO. Some guys worry about the trunions in them but the failures are sporadic and pretty uncommon all things considered. Comp sells a replacement bearing kit thats sealed to avoid these issues but just because its the new best thing doesnt mean its better. They are to new for me to say get em and forget about it.
Anyways the thing that makes the stock rockers good for high RPM is the very VERY small tip which reduces the inertia carried by the rocker arm and makes it easier on the valvetrain to handle. Less weight in your valve train = more high RPM reliability
SweetS10V8
04-21-2010, 09:11 PM
IVe seen too many people pulling these out of the bottom of their oil pan. I know with a high dollar engine especially I wouldnt risk it. The Comp trunion upgrade is CHEAP insurance.
http://inlinethumb07.webshots.com/17734/2517562470060344825S600x600Q85.jpg (http://rides.webshots.com/photo/2517562470060344825OgYSLS)
I just recently upgraded my own set of L92 rocker with the Comp trunions myself.
http://inlinethumb31.webshots.com/35486/2718162550060344825S600x600Q85.jpg (http://rides.webshots.com/photo/2718162550060344825FtKxSU)
The Comp trunion upgrade is CHEAP insurance.
Maybe. Maybe not. Time will tell
That said its not often at all that stock LS equipped vehicles barf out the bearings in the stock rocker arms. I've seen many a truck thats had the tar pounded out of it with 300K plus miles on it and never an issue with them. I think a lot of these rocker arm failures are from too much spring pressure or piss poor build quality. There are some failures yes... but not a lot IMO especially when you remove the " I read this online so i can do anything " engine builder factor and apply that to the so called failures we see
Not many pro shops seem to have high failure rates on them. At least not that im aware of
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