NHRA STOCK valve job

[fdicrasto]

Kenyonizing worked 50 years ago. Curious if thats legal.

[Walter R. Malik]

There are certain things that even though they are deemed illegal, they never bother checking in tear-down ... One is valve seating angle as long as the entire valve job width meets the rule.

The thing is...... there is no more rule.

As written, the rule states, “any valve job permitted”.
From what I can see, the only wording in that entire section pertaining to the valve job states that anything is legal.
All wording regarding total valve job widths, seat angles, etc was omitted from the head section years ago.

So, if you set a record and are in the tear down area and they’re looking over your heads....... and let’s say your heads originally had 45* seats and now they are 50*.......
A- are they even going to check, because there is no longer a valve job rule?
Or
B- if they check, do they care?(because there is no valve job rule)
Or
C- they check, and tell you the 50* seats aren’t legal.
If it’s C....... what rule are they going to point to in the rule book to show you the stock angle has to be retained?

I haven't been personally involved in "Stock" for more than 10 years and I have heard that NHRA has "dumbed down" the rules for new tech inspectors because they don't have the knowledge for enforcement.

An engine I built back then didn't get booted but,
the owner was told to not come back with that bottom angle too deep, like they were.

Obviously ... things have changed.

[CGT]

I have heard that NHRA has "dumbed down" the rules for new tech inspectors because they don't have the knowledge for enforcement.

I know some people working for NHRA as tech inspectors. And I can tell you...these people wouldn't know what they are looking at for the most part...and I certainly wouldn't trust what determination they may come up with.

[Ron E]

I'm involved with several stockers and have been for 10+ years. The tech guys aren't dummies.They are there to keep things from going out of control. That's the reasoning for P/N checks, runner and chamber volume checks. Without them we'd have big chiefs on Stockers in no time. They don't have time to check valve seat angles.They are more "big picture" these days. They are keeping racers in line as much as possible under the circumstances.
Running in any type of racing with rules involves learning what will, and won't go through tech. None of it is in writing, so there is a learning curve to go through.

[nhrastocker]

The problem is that many believe that a Stock Eliminator car goes fast only because the engine.

There will always be those that complain because they do not want to spend the money and work on their car to make it go fast.
I know of many racers that have great and powerful engines, nevertheless, they do not have the right transmission, torque converter or clutch, the right gears or a suspension that works and have not maximized the car/engine combination.

[PRH]

They don't have time to check valve seat angles.

Whether they have time to or not...... with the way the rule currently reads...... why would they? And what would they even look for/look at?


The entire description of the valve job is “any valve job permitted”.
That’s pretty cut and dried to me.

[1972ho]

I agree with PRH it seems like some of the stock/superstock racing think that they running a non hobby racecar and that tech almost need to have body template put on the cars to make sure everyone is legal.And know most them know that most of the cylinder heads have been modified and for the most part NHRA really does care.They know nhra is not going to spend the money to bring in some high paying engine and cylinder head tech. to police a basic bracket classes with occasional heads race.And if someone breaks a record there not going to take the tech.people out the race to tear down someone engines that can take hours to do.So just do what ever valve job you wish that gives the best flow for your deal and don’t sweat it.

[Ron E]

They don't have time to check valve seat angles.

Whether they have time to or not...... with the way the rule currently reads...... why would they? And what would they even look for/look at?


The entire description of the valve job is “any valve job permitted”.
That’s pretty cut and dried to me.

Which is why they turned the seat rules loose. There used to be strict rules and checking was time consuming. They had to prioritize. It's better for them and us.

[PRH]

When I saw the rules had all the wording involving seat angles and max top above OD, etc, removed from that section my first thought was, “they don’t want to bother checking it anymore”.

In my mind the wording was clear. Take it at face value...... any valve job permitted.

Yet, I’d still read things and hear things where people are clinging to the notion that the stock seat angle must be retained.

[Ron E]

When I saw the rules had all the wording involving seat angles and max top above OD, etc, removed from that section my first thought was, “they don’t want to bother checking it anymore”.

In my mind the wording was clear. Take it at face value...... any valve job permitted.

Yet, I’d still read things and hear things where people are clinging to the notion that the stock seat angle must be retained.

I agree 100%.

[BradH]

PRH - Do you do the seat & valve work on your friend's Pontiac stocker?

If so, would you want to change the configuration based upon the the rules (or lack of) stated above?

[PRH]

When I originally did the heads for his car there were still a lot of rules pertaining what could and couldn’t be done with the valve job.
All of the original dyno testing was done with the heads done that way, and many cams had been tried through the years.
The car is in a pretty good place right now, and I don’t feel like changing the valve job would pay any dividends, without the need to change something else to go along with it....... particularly the cam.

If we were starting from scratch with that combo, I’d probably look at doing something different with the valve job/and cam....... but with how it runs now, and taking into account the AHFS is in place, I don’t think it makes any sense to go down that road just yet.

[Greenlight]

Any "cut" that is concentric with the valve guide is legal.

No grinding marks, must be cutter marks. The "cut" can extend into the combustion chamber or below the valve angles.

Any number of angles and any angles are allowed.

[COMP461]

So you can cut in to the chamber off mandrel as long as it’s a machined cut and the chamber holds to volume. Do they car if your chamber is too large

[mag2555]

They don’t care if the chamber checks out larger then minimum.