Roller Rockers in Stock

[Alan Roehrich]

Originally Posted by 69Cobra

I truely believe that alot of these rule changes in stock from the open duration on the cams to valve jobs to any springs and spring pressures are due to the lack of qualified techs to police these rules. Policing rocker arms is not an issue obviously but I think all the other rules have just lead to this as the week link for now. Which is what you are saying.

Well, that is part of what I'm saying. They've kept opening the rules and escalating the cost over the years until Stock Eliminator is already far beyond the intent and spirit of the class.

Policing rocker arms will become an issue as soon as you allow aftermarket roller rocker arms in the class. The question will be whether or not NHRA bothers to address the issue fully and completely. For the answer to that, look at how limited tech inspection has become at the vast majority of NHRA events.

I'm really not going to go in to who it was I talked to, nor the changes possible with roller rocker arms. I'll just say that it absolutely will drive the RPM range up, again, and they will create breakage that is not now happening, whether it will be valvetrain breakage or other failures due to higher RPM ranges depends on several factors, and the combination being considered. It also will certainly drive the cost to remain competitive much higher than a simple set of $300 roller rocker arms and possibly a new set of $100 rocker arm studs.

Let's just make this plain and simple. A racer has reached the point where he is breaking rocker arms, and can no longer continue to increase the RPM range he runs and the valvespring pressure required to run there. So he's reached a limit. Give him roller rocker arms. Now, do you really think he's not going to go get a new set of valvesprings , turn another 1000 RPM, and start looking at what he needs to do in order to get more duration in his camshaft in order to turn even more RPM? Of course he's going to make all of those changes, if he wants to go fast and be competitive.

A real racer will always push the limits. Replace the part that breaks, and he'll go find a way to break even more parts. The new replacement part will always create the need for new parts to go with it, and the opportunity to buy new parts to take advantage of the latest rule change.

Every time you allow something like this, it creates the need to spend even more money for other parts to go with it, and further increases the operating range and parts breakage.

Just look at what has happened to Super Stock. We're now running 9,000 RPM, with belt drives, shaft rockers, huge roller lifters, valve springs with 1000 pounds open pressure and 400 pounds seat pressure, titanium retainers, massive camshafts with as much as 0.900" lift at the valve, and all sorts of other parts that were seen only in Pro Stock and Competition Eliminator just 20 years ago. Most of that was brought on by allowing ported an polished heads, because NHRA did not want to be bothered with stopping them. Is that where we want to take Stock Eliminator?

[69Cobra]

Originally Posted by Alan Roehrich

Well, that is part of what I'm saying. They've kept opening the rules and escalating the cost over the years until Stock Eliminator is already far beyond the intent and spirit of the class.

Policing rocker arms will become an issue as soon as you allow aftermarket roller rocker arms in the class. The question will be whether or not NHRA bothers to address the issue fully and completely. For the answer to that, look at how limited tech inspection has become at the vast majority of NHRA events.

I'm really not going to go in to who it was I talked to, nor the changes possible with roller rocker arms. I'll just say that it absolutely will drive the RPM range up, again, and they will create breakage that is not now happening, whether it will be valvetrain breakage or other failures due to higher RPM ranges depends on several factors, and the combination being considered. It also will certainly drive the cost to remain competitive much higher than a simple set of $300 roller rocker arms and possibly a new set of $100 rocker arm studs.

Let's just make this plain and simple. A racer has reached the point where he is breaking rocker arms, and can no longer continue to increase the RPM range he runs and the valvespring pressure required to run there. So he's reached a limit. Give him roller rocker arms. Now, do you really think he's not going to go get a new set of valvesprings , turn another 1000 RPM, and start looking at what he needs to do in order to get more duration in his camshaft in order to turn even more RPM? Of course he's going to make all of those changes, if he wants to go fast and be competitive.

A real racer will always push the limits. Replace the part that breaks, and he'll go find a way to break even more parts. The new replacement part will always create the need for new parts to go with it, and the opportunity to buy new parts to take advantage of the latest rule change.

Every time you allow something like this, it creates the need to spend even more money for other parts to go with it, and further increases the operating range and parts breakage.

Just look at what has happened to Super Stock. We're now running 9,000 RPM, with belt drives, shaft rockers, huge roller lifters, valve springs with 1000 pounds open pressure and 400 pounds seat pressure, titanium retainers, massive camshafts with as much as 0.900" lift at the valve, and all sorts of other parts that were seen only in Pro Stock and Competition Eliminator just 20 years ago. Most of that was brought on by allowing ported an polished heads, because NHRA did not want to be bothered with stopping them. Is that where we want to take Stock Eliminator?

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.

[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.