Well I stumbled across the info randomly, but then thought why not give it a shot and started to look a bit further into it.
I have absolutely no idea why it is unheard of, maybe its just a little known fact to rwd sr20 enthusiasts that they even exist. As for broken rocker arms, from what I can gather, it isnt the arms design or even the material it is made from that is the problem. The reason they break is when they become dislodged from the pivot of the lifter and float/shift to one side, then when the cam rotates the lobe back onto the shifted rocker arm the force of it trying to open the valve is too much for it to withstand in the position that it is in and with the lifter applying force in the unusual spot that it may be resting on they then snap.
The only two causes for the rocker arm to lift or float that I am aware of is either the hydraulic lash adjuster (lifter) bleeding down at high RPM causing an excessive clearance between the pivot and the rocker arm and then the float occurs... or Valve bounce at high RPM causing the two feet to lift off of the shims on the valves, this clearance then leading to the shifted rocker arm.
As you mentioned, rocker arm stoppers are one of the fixes... they do work pretty well in keeping the rocker planter firmly on the lifter but they dont eliminate the possibility of the rocker arm floating all together. This is where solid lifters come into play to eliminate the possibility of it floating from the pivot and stiffer valve springs to make sure no valve bounce ever occurs.
I think I covered it all in there lol. Anyway, I am running the RAS, Solid lifters and stiffer valve springs which will bring the chances of a broken rocker arm down to very bloody low
A bit sidetracked, but none of the broken rocker arm issues were why I was considering the roller rockers for my build. After a bit of reading I had found that due to the lesser friction between the rocker arm and cam lobe the RR engines were found to have more grunt down low and a better torque curve... partially due to their higher comp ratio as well which I will also be using to my advantage in my build (If machining permits a 10:1 comp)
The RR engines also run without the oil rails above the cams because they dont need them as the friction is so low... Thinking I might keep mine for peace of mind though
As for links... sorry, all of the info I got was from an hour or so searching google and thread after thread on various forums to piece together the relevant info. All very vague, I could not find anyone who had said they have RR's in their DET head and they work fine with proof... massive grey area.
but here are a couple of pics of the RR's
3mm is ALOT of pre load isnt it Luke lol. Im thinking that with the fact the tomei ones have the ability to compress further and with a stiffer spring rate that it should be fine...
Edited by Darryn, 26 September 2012 - 07:02 PM.