856 replies to this topic

[Longdaddy]

if this is to be fixed, we all should understand the history of "plunge cut" rules, who proposed them, and who lobbied for them (and what arguments were used). I'll start with results of a quick search of this very board (and what appears to be its predecessor). I am sure there are many here who can add more factual history...

 

2010:

http://forum.specmia...46;t=000109;p=0

 

Jim Drago

East Street Auto Salvage: 

"The rules were written to clearly define what can and can not be done in the engine. The goal was to spec a good head, not an unobtainable head, but a good one. There are specs, weights, parts numbers on almost every internal engine piece. The head work is spelled out with dimensions on any and everything that matters. I really see no "gray" areas left for pro engine builders to gain an advantage other than with exceptional machine work and attention to detail in the assembly. Do not underestimate that as it is still a very important, if not the most important part of the process." 

 

Jim Drago

East Street Auto Salvage: 

"In my opinion, pro builders who were pushing the envelope on what they were doing before these rules will lose some HP for sure and local guys who were building engines themselves using local NAPA should pick up a little HP by building their engine to the specs with good machine work and assembly. This rule set should definitely tighten the gap between the 'haves" and the "have nots" not grow it"

 

Bob Thornton
http://www.raceengineering.org:

"The new rules will clarify some commonly asked questions and allow those who choose to build their own engines to do so. Like Jim said "The professional engine builder will have an advantage, but it is a lesser advantage which is much better for the class as a whole."

Like many others I have been concerned about the health of the class and as I make my living from Spec Miata it clearly is advantageous, where I am concerned, for the class to be as healthy as possible.

"

 

2013:

http://mazdaracers.c...ack-sm-changes/

Dan Tiley Mechanical Engineer,Ti-Speed, Inc.: 

"No really, I'll take (part) of the "blame" for this rule change.  I measure the FACTORY plunge cut depth of every port in every cylinder head I build.  Out of 12 heads, I had 4 heads that had at least one port that was cut from the factory greater than 9mm before I had even started cutting!  I even had a couple outliers that were as high as 14mm.  In the SMAC committee we decided that it made sense to open the 1.8L plunge cut depths to the same value as the 1.6L due to the high probability of someone being falsely found non-compliant for running factory equipment.  "

 

Jim Drago East Street Auto Parts :

"This change was made to include so many of the heads that were non compliant from Mazda. The change replicates the existing rule in the 1.6 heads. 

 

I have many calls about " do I need to send my head back to be updated" ABSOLUTELY NOT! There is no gain going down the 12mm, if anything it is detrimental as it slows the air charge. However it does make many of the heads usable that were not before. Also, the heads are no longer available new, so we only have what is out there right now."

 

 

 

 

 

 

 

 

[Caveman-kwebb99]

 Also, the heads are no longer available new, so we only have what is out there right now."

 

 

If that is really true we pretty much have close to a disaster on our hands...

[Todd Green]

Now I am just a simple man so I may be unfounded in my beliefs, that is why I have continued to ask this same question over and over and those that are all spun up about this seem to be declining to answer this question...

 

Charlie Hayes posted, "It took until Saturday to determine that all but the #88 failed the protest. I was in the room looking at both the #88 head and my #22 head and yes there was a difference and yes my grandma could notice it"

 

So presumably the #88 car's engine builder was able to do what you are asking.

 

Edit: Ninja'd by Bruce.

[Caveman-kwebb99]

Charlie Hayes posted, "It took until Saturday to determine that all but the #88 failed the protest. I was in the room looking at both the #88 head and my #22 head and yes there was a difference and yes my grandma could notice it"

 

So presumably the #88 car's engine builder was able to do what you are asking.

 

it is also possible that engine builder did not re plung cut...  

 

I am afraid to presume anything anymore to honest...

 

also if the tech people were looking for deburring and blending rather then any amount of material taken away would they even see it? I have no idea I have never been in the tech shed like that

[Ken SM94]

kwebb, your question has been answered several times.  Please do your own research, we can't help you.

[Blake Thompson]

 

 Also, the heads are no longer available new, so we only have what is out there right now."

 

 

If that is really true we pretty much have close to a disaster on our hands...

 

 

Between Me, Tom, Mark and Steve there's no reason to suggest the end is nye.

[Caveman-kwebb99]

ken sm nobody has answered the question.  people just think its possible that doesnt make it so.  

[Bruce Wilson]

Kyle, your question hasn't been answered to your satisfaction because of its wording.  Why don't you just ask if you can plunge cut and still be legal.  The answer to that is yes.  Again, photos would help the conversation for everyone and their grandmothers

[Caveman-kwebb99]

Kyle, your question hasn't been answered to your satisfaction because of its wording.  Why don't you just ask if you can plunge cut and still be legal.  The answer to that is yes.  Again, photos would help the conversation for everyone and their grandmothers

 

seems to me maybe not, my wording is not tricky.  i also believe that is why nobody has answered to my satisfaction.  if any material is removed at all form the short side radius or whatever then it would be illegal...  that is the wording of the rules used in this protest and what has this contreversy going.

 

I am sure beyond a shadow of a doubt that my head has been deburred and I have never looked at it so its not like I am trying to dump dirt on anyone I just think that we need to really come to grips with what can really be done withthe rules worded as they are.

 

I could look at a picture and i am sure i can tell if it was deburred but dooubt i coudl tell if it was just plunge cut and some insignificant amoutn of material was taken away.  again just my common sense talking here.

 

so back to the lynching!

[Adax]

Kyle,

 

Doesn't 9.1.7.4 answer your question?

 

No aluminum in the bowl area (other than that specified
for the plunge cut) or the ports may be removed, added,
or manipulated for any reason.

[Caveman-kwebb99]

Kyle,

 

Doesn't 9.1.7.4 answer your question?

 

No aluminum in the bowl area (other than that specified
for the plunge cut) or the ports may be removed, added,
or manipulated for any reason.

 

it doesnt answer the question of if replung cutting can actually be done without removal of material, the rule just states in one area you cant remove material from there and another rule states you can plung cut.  Jim said early on it can not be replung cut without removing some material, just checked with another engine builder who said I can trust what my engine builder said.  

 

Still have not had an engine builder say anything to the contrary, meaning damn near everything in SM is illegal so we can just lynch everyone at this point.

[KW78]

I have read 428 posts today after getting back from a long NASA weekend.  Wow just F'n wow covers most of my thoughts.

 

I am not going back and cut and past quotes, just will make an effort to remember accurately.

 

Someone said the sky isn't falling in SM.  Not sure about that, it is here in the Rocky mountain area.  Last time we did this when 5 of 6 cars valve jobs were illegal at Road America, so a tech shed rule was made and there were no DQs, was the last time many racers from around here towed to the runoffs in SM.  Was the 09? 010?  Can't remember.  We haven't had any good fields this year in the majors or regionals.  Will this follow suit to say, the northwest?

 

Someone said we are all cheaters, and could spend 10 minutes with any car and find it non-compliant...  THAT IS SO CORRECT!  Show me where you are allowed to not run with a full washer bottle, as the car came delivered with that full, and if it doesn't say you can empty it, you can't...  Ridiculous?  Maybe, but it is 6 pounds of high front weight...   The problem here is that SCCA some years ago said it was too difficult to quantify a competitive advantage, so we will go with the black and white letter of the rules.

 

THIS CONCEPT HAS BEEN OUT GROWN.

 

Someone said the short side radius doesn't matter much.  It really does.  Someone said if you flow a head you will see big changes at low lifts...  you will.   In fact I think it impacts above 6000 rpm IMO, it did on V8 work.

 

I applaud anyone trying to keep the playing field level, but I can promise I can't pony up $14K to see if people are legal.  I also promise that I feel like a great driver with a fatter torque curve will do better that a great driver without that, so I think little things do make a difference.

 

We are trying to control performance with a spec collection of parts, and a spec collection of machine operations done to them.  That is a lot of variables, and I think we could re-address the class philosophy on doing that.   A single source sealed engine may be one way to do that, but as someone said here, there are lots of big wallet ways to get a couple HP from that too.

 

Let's consider what a majors event tech shed is capable of.  I pick that because the runoffs has extra time and manpower.   If we are re-writing any rules let's make sure they are engineered to keep those events legal.

 

Oops have to go.

 

Kyle

[Tom Sager]

A picture is worth 1,000 words.  Probably several thousand in this case.  If anyone is willing to share a pic or two of a non-compliant head, it would help many of us better understand the nature of the issue.  

[Brandon]

Kyle,

Not to get drug into things here, but the rule states quite equivocally the following things:

You can plunge-cut a valve seal area down to a specified depth.

This cut must be in a parallel plane to the position of the valve (not shifted off-center in any direction) and is intended to enable the use of a head which might otherwise be unusable without realigning the valve's position.

 

By performing this cut, you may end up cutting into the STR area of the port.

If you do "remove metal from the STR area of the port" you are not permitted to smooth/deburr/modify/remove any additional metal outside of the previously allowed plunge-cut.

 

It's quite simple:
You are permitted to do operation A.

If you do operation A, you may possibly modify object B.  Though you are not allowed to perform operation C to mitigate any disadvantages from impacting object B via operation A.

 

Now, getting the proper definition of what A, B, & C are is what will settle-down to those who I lovingly refer to as "rules whores".

[Jamz14]

I

 

Someone said we are all cheaters, and could spend 10 minutes with any car and find it non-compliant...  THAT IS SO CORRECT!  Show me where you are allowed to not run with a full washer bottle, as the car came delivered with that full, and if it doesn't say you can empty it, you can't...  Ridiculous?  Maybe, but it is 6 pounds of high front weight...  

Total red herring and BS. I understand your point but your example is crap. Give us another real example to debate.

[Kyle Freiheit]

 

NA TOP

NB Bottom

[Tom Phillips]

Because the wording on the STR is in a separate sentence one could play the lawyer and argue that the qualifier in parentheses about the plunge cut doesn't apply to it, but obviously this is not the intent of the rules. Maybe the last sentence should be removed or changed to clarify this so that no one can misinterpret it in the future, but that doesn't change what is already legal and illegal.

[john mueller]

In the short term I am working with a clarification on the plunge cut rule for the 2014 Western Champs. This is an attempt to remove some of the subjectivity that the current rule has. It's a guideline for what will be acceptable and what will not be for the Western Champs and any remaining 2014 NASA events.

 

​Again, this will NOT be a new to a change to the current rule, just clarification.

 

However, FWIW I am not in favor of making the now found 'illegal' plunge cuts acceptable under the 2015 rules.  I believe NASA has led the way when things got dicy and this is no different.  NASA has a great track record across many makes and models of cars for leveling the playing field and this will be no different. 

[Chris70]

Kyle,

Not to get drug into things here, but the rule states quite equivocally the following things:

You can plunge-cut a valve seal area down to a specified depth.

This cut must be in a parallel plane to the position of the valve (not shifted off-center in any direction) and is intended to enable the use of a head which might otherwise be unusable without realigning the valve's position.

 

By performing this cut, you may end up cutting into the STR area of the port.

If you do "remove metal from the STR area of the port" you are not permitted to smooth/deburr/modify/remove any additional metal outside of the previously allowed plunge-cut.

 

It's quite simple:
You are permitted to do operation A.

If you do operation A, you may possibly modify object B.  Though you are not allowed to perform operation C to mitigate any disadvantages from impacting object B via operation A.

 

Now, getting the proper definition of what A, B, & C are is what will settle-down to those who I lovingly refer to as "rules whores".

Best summary of the situation so far.

Ademir

S.A.C. racing

[MPR22]

Because the wording on the STR is in a separate sentence one could play the lawyer and argue that the qualifier in parentheses about the plunge cut doesn't apply to it, but obviously this is not the intent of the rules. Maybe the last sentence should be removed or changed to clarify this so that no one can misinterpret it in the future, but that doesn't change what is already legal and illegal.

You are dead on Tom.  In the world of legalease, the last sentence should be modified to read.

 

No aluminum in the bowl area (other than that specified 

for the plunge cut) or the ports may be removed, added, 

or manipulated for any reason. It is understood that 

heads may look slightly different from bowl to bowl due 

to casting irregularities. No material may be removed or 

added from the short turn radius in the port, except as allowed for the plunge cut previously mentioned in Section 9.1.7.F.3 and Section 9.1.7.F.4

 

That clarifies the plunge cut is not excluded if it falls within the rules of the previous sections. 

 

What is not clear by the rules, no matter how clear the authors thought they might have been, is where the area of STR begins and ends.  I would bet a large some of money that 90% of the competitors in SM could not point to the STR if given a photo of a cylinder head.  I would even wager that 95% of the tech officials couldn't do it without a manual with diagrams.  (not a dig at Tech, just would be helpful as you are asked to be all knowing and that is just silly).