OK, Stocker "valve jobs".
 

This got started in a "Builds" thread and the way Tech is in the 21ST century and the way the Rule Book is written (to resemble a pirate's treasure map), Wazzup?
Anybody?

Re: OK, Stocker "valve jobs".
 

Good morning Billy and to all,
What is it you'd like to talk about?
I thought that the " valve job " question was answered, it is not done the way NHRA used to specify pretty clearly in our Old Rule Books. If you find a better valve face / seat angle for your cylinder head you can perform that as long as you are going to use the Stock Valve size for your engine combination.
Incase I've missed something here, please let me know.
Its tough living under a rock.

Respectfully,
Henry Kunz 1534 H/SA

Re: OK, Stocker "valve jobs".
 

CYLINDER HEADS
Must be correct casting number for year and horsepower
claimed, per NHRA Technical Bulletins or NHRA accepted.
Porting, polishing, welding, epoxying and acid-porting
prohibited. Combustion-chamber modifications prohibited.
Cylinder heads are additionally restricted in that they must
retain original-size valves at original angles +/- 1 degree
and must be able to hold original cylinder-head volume per
NHRA Specifications. Runner volumes may not exceed
the current Super Stock cylinder-head volumes as listed
on NHRARacer.com. Regardless of the poured volume
measurement, any modifications to intake or exhaust runners
prohibited. Any evidence of modifications from the original
castings will be grounds for disqualifications as determined by
NHRA in NHRA?s sole and absolute discretion. Any aftermarket
steel valve permitted, must retain stock head and stem
diameters. Only engines OEM-equipped with sodium-filled
valves may use sodium-filled replacement valves. Titanium
prohibited except OEM. Hardened keepers permitted. Lash
caps prohibited. Valve-diameter tolerance: +.005-inch or -.015-
inch from NHRA Specs. The following are prohibited: spark-
plug adapters; any grinding in ports or combustion chambers;
removal of any flashings; sandblasting or any other modification
to cylinder head; any film coating of intake and exhaust
runners; any film coating of combustion chamber. Runners
and combustion chamber must retain OEM appearance. Final
Stock Cars Section 11A, page 4STK
acceptance as determined by NHRA in NHRA?s sole and
absolute discretion. External modifications prohibited. Intake
side of head may not be cut into any part of valve cover bolt
holes. Valve-cover bolt holes must remain unaltered and in
their original location. Intake manifold bolt holes must remain
unaltered in their original location. Heat riser passage may be
blocked from intake manifold side of cylinder head. Blocking
passage down in valve pocket prohibited. The following are
permitted: polylocks, jam nuts, screw-in larger-diameter rocker
studs or pinned studs, bronze-wall valve guides, cylinder head
studs. Valve spring umbrellas optional. Cylinder head may have
all of the seats replaced. Any valve job permitted, O-ringing
prohibited. Exhaust plates prohibited.

This is off of TODAY'S NHRA Rules page and as far as I can see, there is no rule revision.

Re: OK, Stocker "valve jobs".
 

The way I'm reading this, the VALVE must retain the original OEM VALVE angle but ANY "valve job" is legal which I would assume (that word again) means any SEAT angles.

Re: OK, Stocker "valve jobs".
 

And if you have the tools, the extra parts and some "research time", you can also explore those two accepted tolerances:
-Cylinder heads are additionally restricted in that they must
retain original-size valves at original angles +/- 1 degree
-Valve-diameter tolerance: +.005-inch or -.015-
inch from NHRA Specs.
It can be negigible or you can have something extra there...

Re: OK, Stocker "valve jobs".
 

Is this a "What would you do" type query?

Re: OK, Stocker "valve jobs".
 

Cylinder heads are additionally restricted in that they must retain original-size valves at original angles +/- 1 degree


The way I read it, is that it doesn't say anything about valve or seat angles, but is talking about valve incline angle.


Stan

Re: OK, Stocker "valve jobs".
 

Okay. Along those lines...
The rulebook seems pretty clear...Okay, it's a little murky, but I read that the valve head angle has to remain OEM, as it's always been.
The valve seat used to allow a 3 angle job, I think a quarter inch wide.
Later, when the use of Serdi type machines, using multiple angle cutters became common, NHRA approved the use of them , at any width.

They also allow the cutter to remove material down below the seat angle and along the sides of the combustion chamber, as long as the machining is done off the guide pilot. I don't see where this is specifically allowed in the rules but it's been done for quite a few years now.
In fact, the latter seems to be specifically prohibited by the book.
Talk about confusing... The guy that reads the book and wants to follow it, is probably leaving a lot on the table.

As far as this thread goes, If anyone is using non-stock valve HEAD angles, please let us in on it and when is it was okayed.
Or is it just a case of creative interpretation ?

Re: OK, Stocker "valve jobs".
 

One degree at 5" is .085". More than one way to "use" that -
Get the valve away from the chamber, or away from the cylinder, in a more advantageous location to the throat/bowl, etc...

Re: OK, Stocker "valve jobs".
 

Please clarify, or re-state another way.
Thanks

Re: OK, Stocker "valve jobs".
 

SBC is 23 degree, SBF is 20 degree, etc.
What's BBC, 24 and 4, I believe, on the intake side.

Re: OK, Stocker "valve jobs".
 

Phil, So you believe that the stock valve angle + or - means you can't re-bore the valve guide hole at a different angle, face off the spring seat to match, change the the valve job sealing angle or possibly install new seats ,at the new angle, and then possibly modify the combustion chamber, which is already illegal? How much could you actually move the valve angle in the head and get away with it? Remember , the approved Stock replacement pistons have to have the valve reliefs at the original angle and depth.
Okay then , if that's what it now means. But it's not what it used to mean, and I go back over 50 years with S/SS tear downs. ;-)

Re: OK, Stocker "valve jobs".
 

Ya know, NHRA is notorious for being very vague and sometimes misleading with the wording of some of it's rules. That IS intentional. Many times I have contacted Tech Inspectors for clarifications and TWICE by TWO different Inspectors I've been told "we don't want you to ask for permission, we want you to beg for forgiveness!"
I will hope that the "any valve job" means what it says and I won't be throwing out a very good set of heads.
OBTW, talking about "valve (stem) angles, have you ever checked a set of SB heads after they've been cut .120 or more?

Re: OK, Stocker "valve jobs".
 

Correct Mark, they do give you a plus or minus ONE degree
Angle milled .120 would be just shy of a degree and a half, so, yes, technically illegal, but only if they actually know how to measure

Re: OK, Stocker "valve jobs".
 

Wouldn't angle milling the deck surface of the heads be a lot less work to basically accomplish the same goal?

Re: OK, Stocker "valve jobs".
 

That's what Billy was talking about

Re: OK, Stocker "valve jobs".
 

Question here, for anyone.
How would tech check the valve incline angle during a tear down, on a canted valve type engine....or any engine , for that matter ?
I don't know, and I've never seen it done.

Re: OK, Stocker "valve jobs".
 

Is it better to do the valve job before or after you port the heads?

Re: OK, Stocker "valve jobs".
 

That right there is some funny... um uh... excrement...
LOL

Re: OK, Stocker "valve jobs".
 

Level the head with deck surface up, and use an angle finder on the face of the valve. Similar to checking "things" out on a floating head type of seat and guide machine. Canted valve check would be the same process.

Re: OK, Stocker "valve jobs".
 

If you angel mill the head enough to change valve angle more than 1 degree in relation to the deck of the block deck, would you have to relocate valves guides to the 23 degree + or - 1degree to be legal in a SBC ?

Re: OK, Stocker "valve jobs".
 

Well, I guess the "proper" way to do it would be to not angle mill the head enough to get into that situation. On occasion, I have angle and flat milled a SB head to get what I need.

Re: OK, Stocker "valve jobs".
 

Will any motor benefit from a 1 or 2 degree valve angle change?
I assume you could angle mill head and install guide and seats at a angle to get as much as possible.

Re: OK, Stocker "valve jobs".
 

Thanks, Phil
With all due respect, I knew how to go about it on a Serdi or similar table.
So, in a few words, it's never gonna happen at an NHRA tear down...
Yet, if this is what this phrase means, here it is,..almost right at the top of the cylinder head paragraph.


BTW where is this spec available for various oddball engines?

Re: OK, Stocker "valve jobs".
 

It would be fun to watch them with a bubble level - "hey, it's almost touching the line, is that a thousandth?" :rolleyes:

Re: OK, Stocker "valve jobs".
 

Always remember to level the level.

Re: OK, Stocker "valve jobs".
 

If My memory is working I believe about 1 degree on a SBC head was .125 angle mill.
I havent looked at the rules in quite a few years and the one thing we used to do that is pretty clear we can't do anymore is pour the heat riser passage completely full of melted aluminum and shape the Ex. valve pocket.

Will a top angle with an outside radius that gets into the chanber wall be considered illegal as a "Chamber Modification? It Could be considered "Unshrouding"

Re: OK, Stocker "valve jobs".
 

Hi Adger, well I guess that it COULD be couldn't it? I guess it would all depend on who's interpreting the rules on that day.

Re: OK, Stocker "valve jobs".
 

I've been doing a +.250 over valve diameter top cut for years. Does wonders for airflow with a BBC ;)

Re: OK, Stocker "valve jobs".
 

Since all the head guys are here, ill ask here?.

How do you raise installed height? Never had this problem before, i have lock/retainers that raise it up but not enough.
1) Sink the valve deeper, but that lowers compression
2) mill the spring seat down

I need around .100 on intake and .140 more on exh, thoughts?

Oh, and the reason i need more height is because my spring pressures are too high. (70-80# too high)

Or am i looking at it wrong???

Not too proud to admit i dont know much!

Re: OK, Stocker "valve jobs".
 

If you know that your spring seat will take the cut without going through or getting too thin/weak then sink the spring seat. I don't know much about 302s but might there be an "offset" retainer (gotta be steel) available? Maybe a combination of both? A shorter spring?

Re: OK, Stocker "valve jobs".
 

Yeah, I agree, the spring should fit the head, not try to make the head fit the spring.

Re: OK, Stocker "valve jobs".
 

Get the correct springs, retainers, locks.
Do not use locks that increase installed height, they lack the strength of a standard or a top lock, which is the strongest lock style.

Re: OK, Stocker "valve jobs".
 

Actually these are springs/retainers/locks that came off a 302 stocker. I'm guessing his valves were sunk deeper or the spring seat was machined, actually, I never asked if he used aftermarket valves, perhaps he used valves with higher lock cuts?

My issue with cutting the valve seat lower is that I would have to start all over with the valve job that I just finished. The spring seat has never been touched, I'll take a closer look and see if .100 is plausible.

I have a set of new mild springs on it now that are at 65 on the seat and 185 over the nose, these are for breaking in the lifters. I could shim them up to get 115/275 or so after break in. (at correct height they are 85/250 or so)

Back out to the garage I go...

Re: OK, Stocker "valve jobs".
 

Seeing as your magic number is .100, more than likely whoever you got the stuff from had .100 long valves. It's just too even a number to be chance.

Re: OK, Stocker "valve jobs".
 

Good morning Jim and to all,
The ideas you have listed will work. You can also find out if your favorite intake or exhaust valve manufacture has valves that are plus .050 and or .100 longer. Then use different assembly height keepers and / or retainers to get to your final height requirement. Have you contacted you valve spring Manufacturer to see if there is some other number valve spring that can accommodate the pressure's you're looking for?
Then you won't have to perform any additional machining processes.
Just a couple of suggestions that might help you, Have a Good Day.

Respectfully,
Henry Kunz 1534 H/SA

Re: OK, Stocker "valve jobs".
 

Well, I sunk the seat of an intake enough to get 1.90 installed height, that gives me 130# on the seat and 290# over the nose. Still on the high side but livable.

Exhaust I sunk it as far as I like it and only got installed height of 1.805 which is still way to short.

I'm going to start calling around for valves +.100 and see how quick I can get them.


(quite the change from a bracket racing engine build!!)

Re: OK, Stocker "valve jobs".
 

I hope that you're cutting up a set of junk heads because by the time that you get done doing what you're doing, you can probably throw them away!

Re: OK, Stocker "valve jobs".
 

All I'm cutting is valve seats which can be replaced and the valves which can be replaced. I get your point though...this is getting rediculous.

So, all I can find is milodon +.050 valves but they are 1.60 so I'd have to cut them to 1.46 so that's no good. Can't find longer stock diameter valves.

Another option is replace the springs which is what I think I'll do. I think I'll stop by Armstrongs again and hopefully they have something in stock.

I mixed and matched the 3 springs and 5 retainers I already have here and so close but not good enough.

Re: OK, Stocker "valve jobs".
 

Jim, not fer nuthin' but do you have a set of "stock", "legal" heads laying around? Take them, do a nice, clean, un-trick valve job on them and find a set of springs that will fit. Someone must make a spring for a "hot street" cam for a 302 that will give you 130-150 lbs. seat pressure. There are gains to be made with a trick-of-the-week valve job, changing seat angles and valve angles BUT you're not there yet and with the combo that you're doing that's the last thing that you need to be concerned with.
You've got a soft HP factor and (for the combo) a decent "stock" head. If you want to sink your intake valves, then go ahead. But not a lot. Sinking the intake will "get the valve out of the way" at low lifts and is a good thing. Don't sink the exhaust valve at all if you can help it. Low lift flow is the opposite on the exhaust side as the intake. Get the exhaust valve "out of the way" by opening it into the chamber so that exhaust gas can flow around it.
The main thing that you need to be concerned with to get started will be blueprinting to get your maximum amount of mechanical compression and don't get carried away with camshaft duration because your duration and "cam timing" will dictate what you will have for cylinder pressure. Cylinder pressure being very important when it comes to making torque and you're not going to make gobs of HP so you had better be able to make torque.
Now "professional" engine builders can (and probably will) come on here and argue my points but with the combo you've got and at the point you're at a well built and blueprinted shortblock and the correct cam selection (and a good set of "stock" heads) will get you a lot farther under the index than what you're doing right now.