stocker cylinder heads
 

Updating some heads to the "new 2009" rules. 1. "any valve job" Does this mean oem valve seat angle no longer applies (go from oem 30 degrees to 45 degrees or oem 45 degrees to 58 degrees?) ? 2. "bowl hawging" will pass tech as long as it is centered off the valve guide? 3. back cutting valves is ok? 4. Has runner volume been changed to account for these modifications (additional 2-3 cc's )? 5. Can heat riser ports be filled? ( "heat riser passage may be blocked from intake manifold side of cylinder head. Blocking passage down in valve pocket prohibited.") Thanks, Ron.

Re: stocker cylinder heads
 

As I understand that is correct,can unshroud to head gasket bore,changing 30 to 45 or ? I think is allowed but have'nt checked,to verify that so I would check on valve angle. To decrease runner CC mill intake/ex surface.
I leave filler 1/8-3/16'' ish down in heat riser passage on bowl side,so it's filled but does'nt protrude into bowl area,and fill all the way to intake surface.
I have another 200 BOP if interested Ron.
Mike Taylor 3601

Re: stocker cylinder heads
 

Thanks, Mike. Phone went dead. Talk to you later.

Re: stocker cylinder heads
 

You better double check! These are stocker heads, right? This is from the 2013 rule book.

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 www.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. Hardened keepers permitted. Lash caps prohibited. Valve-diameter tolerance: +.005- inch or -.015-inch from NHRA Specs. The following are prohibited: spark-plug adapters; cylinder-head studs; 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 acceptance as determined by NHRA in NHRA’s sole and absolute discretion. 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. 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. Valve spring umbrellas optional. Cylinder head may have all of the seats replaced. Any valve job permitted,O-ringing prohibited. Exhaust plates prohibited.

Re: stocker cylinder heads
 

The key thing in this is any valve job permitted.

Re: stocker cylinder heads
 

Yes. But can't unshroud

Re: stocker cylinder heads
 

Might have been told wrong but was told .250'' total or .125''per side bigger than head of valve was took out, and now could be cut to gasket, this unshrouding has to be done off guide center line as guide and seat machine would cut.
Mike Taylor 3601

Re: stocker cylinder heads
 

Refers to max top cut on seat. Thanks.

Re: stocker cylinder heads
 

I was told by more than one tech man that you could do anything in the bowl area as long as it was done with a cutter off the valve guide. Combustion chambers are a different deal.

Re: stocker cylinder heads
 

Greg, I think you are wrong about using a cutter to cut to the bottom of the bowl, According to division 5 tech director. And It's up to person checking your heads if it's legal and you can't appeal there ruling. Tom

Re: stocker cylinder heads
 

Tom , One throat cut ,any angle, off the center, as far as the guide boss allows.
Been doing that since '09 out here.
Several teardowns...

Re: stocker cylinder heads
 

Tom, Wayne seems to go by different rules than the rest of the country.

Re: stocker cylinder heads
 

Bachelder says different. You can go as deep as the guide or guide boss will let you, so long as the cut is concentric with the guide. I was standing there at the NHRA booth when he said it. The rules are pretty loose regarding the top cut as well.

And they absolutely, positively, will NOT give you an answer in writing regarding angles, or the legality of using a radius seat. Apparently, every tech inspector KNOWS what "looks right" for each individual head. :rolleyes:

Re: stocker cylinder heads
 

"stock heads " ?? lolololololololool................................ .mine were too stock and probably would not make it through the barn...stock ain' t stock anymore

Re: stocker cylinder heads
 

most of these statements seem to be wishful thinking that it will pass- I think someone hit it on the head (haha) that each division has a different interpertation on what is ok- Indy seems to be who can sidestep the issue and get there guy past the others-the tech statement I heard was -you do what youve got to do- the problem is this attitude has gotten us to where we are now

Re: stocker cylinder heads
 

Richard, I do not know about the rest, but my statements are based purely on person to person discussions with division tech guys who I know personally and respect, and with Bruce Bachelder.

The idea that you cannot appeal a division level decision on heads is something I have yet to see proven, as I have seen exactly that done.

Again, my biggest problem, and I will not mention by name the division people who told me this, is that you cannot get a definitive answer in writing about vave jobs. I asked specifically about a radius seat valve job, since stock angles are no longer required. I was told maybe, maybe not, depending upon whether the tech inspector involved felt that it "looked right on that head". That's a bogus answer. If we are no longer restricted to stock seat angles, nor restricted on the number of angles, it does not matter if it "looks right", a radius seat is either legal or not. Or at least it should be either legal or not.

Re: stocker cylinder heads
 

You are exactly right Alan. I inquired about a radius seat when the change first came out and was told exactly the same thing. Maybe - Maybe not and no letter forthcoming. I have been inquiring about every two weeks since with the same results. I can't undertand what is so hard about legal or illegal but I have been thru this before and I'm sure I will go thru it in the future. Problem with that is: by the time I am told it is ok it is 2 - 3 years later and I see racers going thru teardown and passing at the same time I am being given the run around.

Re: stocker cylinder heads
 

Alan, the problem is that they don't know what you are referring to when you say radius seat. LT1 & LS1 heads came from the factory with radius cut seats from the bottom of the seating angle to the throat (bowl) and by the letter of the previous rules were illegal. So to make it easier for tech, I think they changed the rule to read any valve job, hence do any valve job - angles - radius - multiple angles - have at it

Re: stocker cylinder heads
 

Bub, you could be right, but I offered to show them the valve seat cutter from Newen. :eek:

Re: stocker cylinder heads
 

You know, I saw this post when it first appeared. I wrote a long, detailed response to what I knew was correct, and what wasnt, pointing out the potential pitfalls. I deleted the post because it just doesnt matter. If you run Stock, take your heads to YOUR techman, have them inspected. Race and set a record in YOUR division. Your life will be much happier.

Wade

Re: stocker cylinder heads
 

Wrong information

Re: stocker cylinder heads
 

Thanks to all who responded. Ron.

Re: stocker cylinder heads
 

Wade you are 100% correct , been there done that ! :confused:

Re: stocker cylinder heads
 

Alan,
You are talking about newen cnc guide& seat machine,that makes all cuts with one insert correct, that or cutting radius on bottom of seat before installing is only way I know to have seat radiused on lower side of seat to bowl area.
When you say radius seat you are talking about seat that is radiused below where valve seats so that it creates a venturi,just making sure we are talking about same thing.

Do you know anyone with Newen cnc guide&seat machine ,watched those videos lots of times,just curious how they are in the real world? Have'nt went to any trade shows for 8 years went every year from Nashville PRI till last at Indy kinda was burnt out on them,may go to Indy PRI next year.

Mike Taylor 3601