Rocker Clarification is up!!!

[denbreeden]

Any aftermarket steel valve permitted, must retain stock head and stem diameter is what the rulebook says, nothing about length.


Dennis Breeden
A/SA

[X-TECH MAN]

Longer than stock aftermarket stainless steel valves ARE LEGAL in stock in both NHRA and IHRA and have been for many years.

[Lew Silverman]

OK! So everyone is right! The rules are clear as mud, but shouldn't be that hard to understand.

Manufacturers tolerances are suspect, so everyone needs to have a little cushion so you don't go over the spec. I don't have the capability of checking the "true" ratio of each of my rocker arms, but if each one is different, I'll have to check the true lift at each retainer, and hope I get 16 measurements that are the same. It's quite possible that will take more than 16 rocker arms to accomplish. Maybe I'll just be happy if they're all below the maximum lift.

I'm really not trying to be obtuse here, just trying to understand why the rules have to be written so vaguely that they invite all of this discussion! Most every other aftermarket part is identified by number in the Guide, for a reason.

Lew

[Billy Nees]

Originally Posted by Lew Silverman

I'll have to check the true lift at each retainer Lew

You don't? Then you're just asking for trouble!

[Stocker 2]

Originally Posted by Lew Silverman

I don't have the capability of checking the "true" ratio of each of my rocker arms, but if each one is different, I'll have to check the true lift at each retainer, and hope I get 16 measurements that are the same. Lew

Its easy enough to do. Check all 16 rockers on one valve, figure the true ratio of each rocker, then check the rocker with the largest true ratio on all 16 valves.

[Bill Edgeworth]

Lew,
The discussion is kind of becoming apples and oranges.
The points I was trying to make are;
1 They should not be tossing people without actually measuring the rocker ratio on their motor
2 Tolerance and advertised ratio are two different things and you need to consider both issues because advertised is often not what it works out to be in real life.
And further to what Dennis and X-tech man said I think the reason they relaxed the valve length rule is that it was very difficult for some racers to find a spring that would give the needed seat pressure and rate and fit all the height, diameter and configuration criteria. (Another can of worms to squawk about for those who don’t like our current spring pressure and duration rules or lack of rules that is)
And as Billy mentioned you better be checking every single one for two reasons; to make sure you are legal and not leave anything on the table.
Doesn’t all this talk about checking stuff make you want to run out and buy a 3 or 4 valve or a V10 stocker? LOL

[theworm]

Originally Posted by mopar jeff

how come when i look at nhra's amendment page this part is crossed out?

either adjustable pushrods or adjustable oem rocker arms permitted on any application, but not both.

does that mean that part of the rule no longer applies?

thats what it sounds like to me they dont care anymore about this.

[X-TECH MAN]

Originally Posted by Lew Silverman

OK! So everyone is right! The rules are clear as mud, but shouldn't be that hard to understand.

Manufacturers tolerances are suspect, so everyone needs to have a little cushion so you don't go over the spec. I don't have the capability of checking the "true" ratio of each of my rocker arms, but if each one is different, I'll have to check the true lift at each retainer, and hope I get 16 measurements that are the same. It's quite possible that will take more than 16 rocker arms to accomplish. Maybe I'll just be happy if they're all below the maximum lift.

I'm really not trying to be obtuse here, just trying to understand why the rules have to be written so vaguely that they invite all of this discussion! Most every other aftermarket part is identified by number in the Guide, for a reason.

Lew

Because most of you guys try to make something out of nothing. Why bother changing rockers in the firt place if your not breaking rocker arms and you still going fast ? The rocker arm is NOT going to give you some out of no where 50 plus HP. The best I have seen or heard of is approx a 3 HP gain on a good DTS dyno and that was from back to back testing of some really screwed up OEM rockers vs a nice set of alum. roller rockers that anyone could afford and buy. Just make sure you lift is correct(not over) and your not trying to use an under cut cam and over ratio rockers or you WILL get cought and DQ'ed..

[Doug McCue]

Originally Posted by Jim Wahl

SECTION 10A: STOCK CARS, ENGINE:1, ROCKERS ARMS (Page 5) (1/19/2012)
"OEM or a Aftermarket rocker arm permitted. Either adjustable push rods or adjustable OEM rocker arms permitted on any application, but not both. Needle/roller bearing pivots and roller tips are permitted for all applications. Must remain same design as original application (i.e. stud mount must retain stud mount, pedestal type must retain pedestal type and shaft type must retain shaft type. Stud girdles prohibited.) Stamped steel OEM and OEM-type rocker arms may be reinforced."


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Can this rocker be in Aluminum or steel?

[Jim Wahl]

Originally Posted by Doug McCue

Can this rocker be in Aluminum or steel?

As per a conversation with Danny at the PRI Show, both are legal. Jim

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