Roller Rockers in Stock

[Alan Roehrich]

Originally Posted by 69Cobra

All very good points. You've personally have taken me from wanting roller rockers in stock to not so much. I guess we'll have to wait for the NHRA rule book to know which way to go here.

Kris, to be quite honest, at first glance, roller rocker arms looked like a decent solution to me as well. However, I learned many years ago, at great cost, to look very carefully at rule changes, and be extremely suspicious of rule changes intended to "save racers money". At least 99 times out of 100, rules that supposedly "save racers money", end up costing them a fortune either right then, or not far down the road.

[Dwight Southerland]

Alan, I agree with all your analysis about the deterioration of the spirit of Stock Eliminator, but using the "quick lift" Crane rockers as a point of "evils" associated with roller rockers is not totally a valid argument. The principles of physics that are designed into the Crane rockers can also be incorporated into stamped rocker arms, and the additional low lift increase can be built into the cam lobe profile.

The addition of roller rocker arms into the current mix of contradictory rules in Stock Eliminator is probably of little consequence other than helping a few applications be more reliable.

[Alan Roehrich]

Originally Posted by Dwight Southerland

Alan, I agree with all your analysis about the deterioration of the spirit of Stock Eliminator, but using the "quick lift" Crane rockers as a point of "evils" associated with roller rockers is not totally a valid argument. The principles of physics that are designed into the Crane rockers can also be incorporated into stamped rocker arms, and the additional low lift increase can be built into the cam lobe profile.

The addition of roller rocker arms into the current mix of contradictory rules in Stock Eliminator is probably of little consequence other than helping a few applications be more reliable.

Dwight, you're absolutely correct, it is possible to make a stamped rocker arm like the Crane, but it would require someone making a very expensive set of dies to stamp it with, and owning a press. You can make an aluminum rocker like the Crane with any good 4 axis CNC machine, maybe even with a 3 axis.

Yes, you can put that low lift aggressiveness in a cam profile, provided you are not already on the edge of the rocker face.

I disagree, there's a lot you can do when you take the stock rocker arm out of the equation.

[MikeFicacci]

I wonder what the real fast guys that have to deal with rocker issues have to say on the subject. Specifically big block Chevy guys. I know a lot of them check these rockers religiously and do have to deal with breakage from time to time. Curious.

[Aubrey N Bruneau]

Once again, I'm going to be offering an opinion in an area that I shouldn't... but that's OK... as long as it makes people laugh.
Right now, isn't pretty much anybody running fast, running the absolute most duration in their cam that they can, due of course to piston-to-valve clearance ????? To me, the guidelines on pistons will ALWAYS set the limit there... and as long as NHRA keeps the piston monitored, more duration just isn't in the cards. That, I think, is good. Seperates us from Super Stock.
So.... roller rockers, in one way or another, brining about another 1000 RPM ?... even 500 ?
Can't see it.
Perhaps a couple hundred, but unlikely in the form of a completely altered torque curve.
For me, just providing reliability when buzzing that last 300-400 RPM over the shift point, when passing through the traps.
A LITTLE piece of mind at 120+ MPH !

Alan... as usual, a little over my head ! HEE HEE !
Though, I DO know exactly what you're talking about with the "variable ratio" rocker arm. INGENIOUS, if you ask me !
Money has always seperated the real players from people like me. I'm OK with that.

BTW... Have I ever mentioned that EVERY TIME I read this message board, I learn something ..... ? !

great place !

[Alan Roehrich]

Originally Posted by Aubrey N Bruneau

Once again, I'm going to be offering an opinion in an area that I shouldn't... but that's OK... as long as it makes people laugh.
Right now, isn't pretty much anybody running fast, running the absolute most duration in their cam that they can, due of course to piston-to-valve clearance ????? To me, the guidelines on pistons will ALWAYS set the limit there... and as long as NHRA keeps the piston monitored, more duration just isn't in the cards. That, I think, is good. Seperates us from Super Stock.
So.... roller rockers, in one way or another, brining about another 1000 RPM ?... even 500 ?
Can't see it.
Perhaps a couple hundred, but unlikely in the form of a completely altered torque curve.
For me, just providing reliability when buzzing that last 300-400 RPM over the shift point, when passing through the traps.
A LITTLE piece of mind at 120+ MPH !

Alan... as usual, a little over my head ! HEE HEE !
Though, I DO know exactly what you're talking about with the "variable ratio" rocker arm. INGENIOUS, if you ask me !
Money has always seperated the real players from people like me. I'm OK with that.

BTW... Have I ever mentioned that EVERY TIME I read this message board, I learn something ..... ? !

great place !

Actually Aubrey, we (read rectangle port big block Chevy racers) are not running all the duration that will fit in the engine, honestly, I don't think that many people are running every bit of duration that will fit. That's all I will say about that, but we can get more cam in the engine, so can many others.

Again if you accept the premise that you need "x" amount of spring pressure to turn "y" RPM, but you cannot run "x" valve spring with stock rockers, your rockers, for what ever reason, will only take "n" valvespring pressure, then yes, roller rocker arms will lead to a significant increase in RPM.

Also, let's just say that if you could go faster turning more RPM, but you need more valvespring pressure and a better rocker arm, you can change the lobe profile so that the valve opens just a bit slower just before TDC on the intake, and make the lobe faster elsewhere. With a really stout valvespring, you can slam the exhaust valve shut faster, only slowing it down slightly in the last 5-10 degrees before it seats.

[Bill Grubbs]

Using GM rocker arms, we have acually broken 3 rocker arms in 5 years, found probably 8 more cracked. Rocker arms are not a problem for us, but we only run a few races a year.

[Jeff Lee]

Like I said...those that want every .001 to .01 will do what needs to be done. The rest, those that obviously will never find the true potential of their combination, just want reliability.

Case in point...I see a LOT of stick racers that could go .20 to .30 quicker with more refined clutches and if not more refined clutches, then more refined tuning. And I'm not here to bash one brand or another, nor I am I hear bashing one racer over another racers clutch driving / tuning abilities. But you see clutch racers that go "all out" looking for every .01 (I would be in that category) and others that give up two tenths or more because the feel they would rather give up ET performance for what they perceive as reliability and repeatability for rounds. And some just don't believe that ET decrease is possible so they don't even explore. Is this any different than the rocker arm debate? In the end, you will have those that want it all and those that just want to get by and have fun. There's a LOT of Stock racers that are just there to have fun and their idea of fun is not breaking parts and not looking for every .001 with cubic dollars.

And I can't say how many but I know there are many out there running roller rockers with hopes they never get caught. Think about that. Racers are willing to risk a one year suspension for a flagrant rules violation. I believe this guys are after reliability and rounds more than anything else.

[Jeff Lee]

Originally Posted by Bill Grubbs

Using GM rocker arms, we have acually broken 3 rocker arms in 5 years, found probably 8 more cracked. Rocker arms are not a problem for us, but we only run a few races a year.

Cracked is broken. Thats 11 broken rocker arms in five years and you have raced "a few" races a year. If that was two races a year, that would be ten races in five years. That's .9 broken rockers per race.
I remember one year Scott Pearson could only afford to race two national events. He won them both. True he races SS/JA but there are many Stock racers like yourself that can't afford to attend many races. Sure would suck if you broke a rocker in a final round! Even first round breakage would cost you a lot of money.

[Alan Roehrich]

Originally Posted by Bill Grubbs

Using GM rocker arms, we have acually broken 3 rocker arms in 5 years, found probably 8 more cracked. Rocker arms are not a problem for us, but we only run a few races a year.

A few?

How many Division 2 races did you and Brenda skip this year Bill? We didn't make the tour this year, we'll be back next year.



We have never broken a rocker arm, not in 6 years, although this year was real short. We've broken one 7/16" rocker stud, the poly lock killed the entire engine, including the block. We have only run near 500 passes on one set of rockers, and maybe 300 passes on the other set. No, we ain't as fast as some, but we haven't lost too many heads up races, we've got 2-3 class wins, and we usually go a few rounds fairly often. It may not be a rocket, but it ain't a slug, either.